Natural History Study Research Articles

Functional Classification of Germline RUNX1 Variants Identified in Patients Suspected of Familial Platelet Disorder with Associated Myeloid Malignancies

RUNX1 is a master regulator of hematopoiesis. A highly conserved runt-homology domain (RHD) located near the N-terminus is responsible for DNA binding and interaction with its heterodimeric partner CBFβ, whereas the C-terminus contains the transactivation domain (TAD). Somatic variants and chromosomal abnormalities affecting RUNX1 are commonly observed in hematological malignancies, such as myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Heterozygous germline RUNX1 variants are responsible for familial platelet disorder with associated myeloid malignancies (FPDMM), an autosomal dominant disorder with incomplete penetrance and a broad spectrum of clinical phenotypes, including thrombocytopenia, functional platelet defects, and an increased risk (35-45%) of developing MDS and AML. In 2019, our group launched a longitudinal natural history study of patients with germline RUNX1 variants to increase our understanding of FPDMM, which will hopefully lead to better clinical management and potentially new therapies. The majority of RUNX1 variants are private with limited segregation data available, making variant interpretation challenging. A significant number of cases have variants of unknown significance (VUS) in RUNX1. Therefore, it is important to determine if these VUS are pathogenic (or benign) in order to improve the diagnosis and clinical management for these individuals. To functionally characterize each variant, we used well-established in vitro functional assays to assess the damaging effect of each RUNX1 VUS, including transactivation reporter assays, electrophoretic mobility shift assays, co-immunoprecipitation, immunofluorescence, and western blot with cell fractionation. All assays include RUNX1 wildtype and known benign and pathogenic controls, as well as co-expression with its binding partner CBFβ. The VUS Ser94Arg located in RHD of RUNX1 has showed impaired CSF1R transactivation (< 20% of wildtype), reduced subcellular co-localization of RUNX1 with CBFβ, and reduced heterodimerization with CBFβ. These results together with population frequency data, in silico prediction, phenotype and segregation data support the reclassification of this variant into the likely pathogenic category. On the other hand, the VUS Asp123His shows no damaging effect in vitro, and could be reclassified to likely benign. Using these assays, we have confirmed or reclassified several RUNX1 variants using the criteria set by the ACGM Myeloid Malignancy VCEP (Luo et al, Blood Adv. 2019; 3:2962). Together, these results highlight the importance of using in vitro functional assays for RUNX1 variant classification. Moreover, we sought to determine the potential of using platelet transcriptomics for RUNX1 variant classification and to gain a deeper understanding of FPDMM pathogenesis. Clariom™ D microarrays identified 218 differentially expressed genes (DEG; absolute fold change ≥ 2; q-value < 0.05) between FPDMM patients and healthy controls, with 90 genes (41%) being upregulated and 128 genes (59%) being downregulated in patients. Hierarchical clustering showed that the selected FPDMM patients with pathogenic and likely pathogenic RUNX1 variants clustered together and separately from healthy controls, with well-established pathogenic variants, such as Arg201Ter and Arg201Gln, at the opposite end of the dendrogram, and likely pathogenic variants such as Tyr403Cysfs153 closer to healthy controls. Our results show that FPDMM patients exhibit reduced expression of important genes related to thrombocytopenia and platelet dysfunction. Furthermore, several top upregulated genes identified in FPDMM patient's platelets are associated with poorer outcomes in AML patients, according to the TCGA dataset. Overall, our study shows the importance of performing functional assays to aid RUNX1 variant classification and to facilitate the study of FPDMM pathogenesis. We are currently analyzing the platelet proteome data of FPDMM patients by LC-MS/MS, which will be reported at the annual meeting.

Quality of Life in Emicizumab-Treated People with Hemophilia A in the ATHN 7 Hemophilia Natural History Study - an Assessment of Baseline PROMIS®-29 Scores

Background: People with hemophilia A (PwHA) experience frequent bleeding into joints, muscles and soft tissues due to a deficiency of factor (F)VIII, which has a substantial negative impact on their health-related quality of life (HRQoL). The American Thrombosis and Hemostasis Network (ATHN) ATHN 7 research study is: A Natural History Cohort Study of the Safety, Effectiveness, and Practice of Treatment for People with Hemophilia (NCT03619863). ATHN 7 prospectively monitors the use of hemophilia A (HA) and B therapies, including emicizumab. The aim of this abstract is to contribute to the literature on disease burden in PwHA. We describe baseline scores for a subset of adult PwHA enrolled in ATHN 7 who were receiving emicizumab and completed the Patient-Reported Outcomes Measurement Information System (PROMIS®) Profile-29 measure at the time of study entry. Methods: ATHN 7 is a longitudinal, prospective observational cohort study conducted at 26 ATHN-affiliated sites in the United States (US). Clinical and demographic information was collected at baseline. Participants completed patient-reported outcome measures, including PROMIS-29, at baseline. The PROMIS-29 Profile is a disease-agnostic measure capturing data across physical, mental, and social health domains: physical function, fatigue, sleep disturbance, pain intensity, pain interference, depressive symptoms, anxiety, and ability to participate in social roles/activities. PROMIS measures are scored using a standardized T-score metric with a reference population mean of 50 and a standard deviation (SD) of 10, based on the US general population. Higher scores indicate the participant is experiencing more of the concept being measured (positive or negative). No statistical comparisons were performed in this analysis. A mean standardized T-score of 0.5-1.0 SD worse than the reference population mean is defined as mild symptoms/impairment, 1.0-2.0 SD worse than the mean as moderate symptoms/impairment, and ≥2.0 SD worse than the mean as severe symptoms/impairment (HealthMeasures, 2023). Results: Overall, 67 participants in ATHN 7 receiving emicizumab at study entry completed PROMIS-29 at baseline ( Table 1). Participants had a median (min, max) age of 30.0 (18.0, 75.0) years. Disease severity at diagnosis was mild or moderate for 14 (20.9%) participants and severe for 53 (79.1%) participants. There were 12 (17.9%) PwHA with FVIII inhibitors. At time of study entry, participants had been receiving emicizumab for a median (min, max) of 126 (13.1, 254.0) weeks. Mean PROMIS-29 domain T-scores for the ability to participate in social roles and activities, and symptoms of anxiety, sleep disturbance, depression and fatigue at baseline all fell within 0.5 SD of the mean of the reference population ( Figure 1). PwHA in this analysis did however, demonstrate mild symptoms of pain interference (mean baseline T-score: 55.62; [normal: <55]). Mean baseline PROMIS-29 domain T-scores were also analyzed according to presence of FVIII inhibitors, disease severity, and age. PwHA with FVIII inhibitors had mild impairment of physical function (42.17 [normal: >45]) and mild symptoms of pain interference (58.64; [normal: <55]), while those without inhibitors had physical function (45.96; [normal: >45]) and pain interference (55.00; [normal <55]) within or on the boundary of 0.5 SD of the reference population. Similarly, people with severe HA without FVIII inhibitors had mild impairment of physical function (44.76; [normal >45]) and mild symptoms of pain interference (55.49; [normal: <55]), while people with mild/moderate HA without inhibitors had physical function (49.85; [normal: >45]) and pain interference (53.46; [normal: <55]) within 0.5 SD of the reference population. Physical function decreased with age, from 51.71 in the group aged ≤24 years (normal: >45) to 36.18 (moderate impairment) in the group aged ≥50 years, while pain interference increased with age, from 51.18 in the group aged ≤24 years (normal: <55) to 59.80 (moderate symptoms) in the group aged ≥50 years. Conclusions: In this analysis, we observed that HRQoL in PwHA receiving emicizumab, as measured by PROMIS-29 domain T-scores, generally did not differ from that of the US reference population. PwHA did report mild symptoms of pain interference. Results should be interpreted with caution given that no statistical tests were performed, and subgroup numbers are small.

Correlation between Peripheral Blood and Bone Marrow Somatic Mutations Among Patients with Suspected or Established Myelodysplastic Syndromes from the National MDS Study

INTRODUCTION: Myelodysplastic Syndromes (MDS) are caused by progressive clonal dominance of mutated hematopoietic stem cells. While assessment of mutations in peripheral blood (PB) is an established standard for monitoring patients with some diseases such as chronic myeloid leukemia, the sensitivity and precision of PB screening and monitoring for somatic mutations in patients with MDS and related conditions such as clonal cytopenias of undetermined significance (CCUS) is less certain. Multiple published guidelines require bone marrow (BM) evaluations for the above, an invasive procedure not often performed outside of clinical trials. We compared somatic mutations and variant allele frequencies (VAFs) in paired PB and BM samples to assess the utility of PB results as a surrogate for diagnosis and monitoring. METHODS: The National MDS Natural History Study (National MDS Study) is an observational longitudinal cohort study of cytopenic patients suspected of having a diagnosis of MDS. All patients have PB and BM sampled when entering the study, prior to formal diagnosis. For this study, paired PB and BM baseline DNA samples from 36 patients were assessed for somatic mutations. Only subjects with minimum of one variant detected in their BM were included in this study. DNA was extracted from PB using an automated FlexSTAR (AutoGen) and from BM cell pellets using a QIAamp DNA Mini Kit (QIAGEN). Targeted exon sequencing of 96 genes was performed using a NovaSeq 6000 at a mean coverage of >1,200X and a mean breadth (bases covered at ≥100X) of >99.9%. Reads were aligned against a patched version of the build GRCh38 using BWA-MEM. VarScan2 was used to detect single nucleotide variants and short insertions/deletions with a minimum VAF of 2% and 5%, respectively. Resulting variants from 53 genes were manually reviewed to retain likely disease-causing variants. Correlation analysis between PB and BM VAFs was performed using Pearson correlation and linear regression. To confirm paired samples were sourced from the same subject, the Somalier software using a set of highly polymorphic SNPs across different ancestries was utilized to ensure a high level of relatedness. RESULTS: The 36 patients included 10 (28%) with MDS, 2 (6%) with MDS/MPN, 1 (3%) with AML (<30% blasts), and 23 (64%) with CCUS. The median age was 73 years (Table 1). Five of 36 patients had circulating PB blasts. Among the 191 mutations identified, the most common were TET2 (27%), SRSF2 (13%), DNMT3A (9%), SF3B1 (8%), and ASXL1 (8%). Correlation analysis of mutations (n=180) shared between paired PB and BM samples indicated a linear relationship between VAFs detected in PB and BM (Pearson correlation r=0.95, Figure 1), with a slight increase in variance observed with increasing VAFs. The deviation from the perfect (grey line) to the observed (yellow line) linear fit indicated that PB VAFs underestimated VAFs in BM by approximately 23% overall (Figure 1). For example, a BM VAF of 0.20 translated to a mean PB VAF of 0.16 based on the regression fit. The lower sensitivity was confirmed when looking at the number of total missed variants (present in BM, absent in PB): 9 of 101 (9%). Two mutations were detected in PB, but not BM. These mutations and diagnoses were 1) ETNK1 (VAF 0.026) in a patient with MDS-EB-1; and 2) CBL (VAF 0.021) in a patient with MDS with isolated del5q. Next, we assessed the relationship between percent of detected mutations and minimum VAF that was detected using linear regression and found that the higher the minimum VAF, the lower the percent of missed mutations. For example, for a 0.1, 0.2, and 0.3 minimum VAF, 11%, 9%, and 8% of BM mutations were missed, respectively. There was no difference in concordance between MDS and CCUS. SUMMARY & CONCLUSIONS: PB can be used to reliably identify somatic mutations in patients with suspected or established MDS and related conditions. Linear correlation between PB and BM VAFs showed, unsurprisingly, that BM mutations with higher VAFs are more likely to be detected. If PB is positive, this method of variant detection may be used potentially to diagnose and monitor. However, if negative (or if VAF is less than 0.10), bone marrow genomics are still necessary to exclude detectable clonal mutations. For quantitative predictive tools that use VAFs, PB VAFs would need to be corrected to improve predictive results; our estimated linear regression equation could be used to guide this in a larger prospective study.

Persistent Albuminuria and Chronic Kidney Disease in Adults with Sickle Cell Disease: Results from a Multicenter Natural History Study

Background: Patients with sickle cell disease (SCD) are at high risk for developing kidney disease. Albuminuria, an early marker of kidney injury, may be initially transient in patients with SCD. Existing guidelines propose confirming albuminuria at multiple timepoints before intervention. A recent study suggests a urinary albumin-creatinine ratio (UACR) ≥ 100 mg/g correlates highly with persistent albuminuria and subsequent decline in estimated glomerular filtration rate (eGFR). We examined a cohort of patients with SCD to assess those characteristics associated with persistent albuminuria and chronic kidney disease (CKD). Methods During routine clinical visits, we enrolled patients with HbSS or HbSß 0 thalassemia between 18 and 65 years at 4 centers into a prospective study to assess the natural history of kidney disease in SCD. We excluded patients if they had bone marrow transplantation, cancer, connective tissue disease, diabetic nephropathy, other glomerular diseases, hepatitis (B or C), HIV, or were on dialysis. Blood and urine were collected for routine clinical laboratory assessments. Serum cystatin C was measured by commercially available ELISA, and eGFR was calculated using the CKD-EPI-2012 cystatin C equation. We defined CKD as an eGFR < 60 mL/min/1.73m 2 or presence of albuminuria. Glomerular hyperfiltration was defined as an eGFR>130 in females and >140mL/min/1.73m 2 in males, respectively. Persistent albuminuria was considered present if 2 or 3 UACR values were ≥30 mg/g or if initial baseline value was ≥100 mg/g (PMID: 32289161). We utilized generalized linear models adjusting for age and sex to identify characteristics associated with persistent albuminuria and CKD. For multivariable selection, we fit binomial or multinomial LASSO regression models adjusted for age, sex, hemoglobin, %Hemoglobin F, hemoglobinuria, and hydroxyurea to identify those variables associated with outcomes of interest. Results Of 284 enrolled patients, 268 had complete data for UACR, cystatin C and serum creatinine at baseline; 104 (38.8%) of these had persistent albuminuria (Table 1). CKD was present in 40.7% of patients and 26.5% exhibited hyperfiltration. In analyses adjusted for age and sex, several factors were associated with the likelihood of persistent albuminuria. Higher hemoglobin, higher %Hemoglobin F, higher serum bicarbonate and use of NSAIDs were associated with decreased likelihood of persistent albuminuria. Higher systolic and diastolic blood pressure, elevated serum alkaline phosphatase, total bilirubin, and white blood cell count (WBC) were associated with an increased likelihood of persistent albuminuria as were presence of hemoglobinuria and use of angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). In multivariable selection, higher systolic and diastolic blood pressure, ACEi/ARB use, leg ulcers, higher WBC, higher aspartate transaminase (AST) remained associated with higher likelihood of persistent albuminuria. Presence of avascular necrosis, NSAID use, and higher serum bicarbonate were associated with lower likelihood of persistent albuminuria. When evaluating baseline UACR, individuals with UACR≥100 mg/g had similar probability of subsequent albuminuria as compared to those with severe albuminuria (UACR≥300 mg/g) [Table 2]. Conclusion Persistent albuminuria in this cohort was associated with multiple clinical features. Lower use of NSAIDs in this cohort likely represents counseling of patients to avoid these due to their kidney disease. The relationship with serum bicarbonate suggests a propensity for metabolic acidosis in these patients which could exacerbate the underlying SCD. These data confirm the predictive value of a single UACR value ≥100 mg/g for persistent albuminuria, suggesting this may be a sufficient trigger to warrant intervention. CKD, hyperfiltration and albuminuria were extraordinarily common, consistent with prior studies and validate use of this cohort for additional longitudinal assessment of kidney disease in SCD.

Characterization of the Cynomolgus Macaque Model of Marburg Virus Disease and Assessment of Timing for Therapeutic Treatment Testing.

Marburg virus (MARV) causes severe disease and high mortality in humans. The objective of this study was to characterize disease manifestations and pathogenesis in cynomolgus macaques exposed to MARV. The results of this natural history study may be used to identify features of MARV disease useful in defining the ideal treatment initiation time for subsequent evaluations of investigational therapeutics using this model. Twelve cynomolgus macaques were exposed to a target dose of 1000 plaque-forming units MARV by the intramuscular route, and six control animals were mock-exposed. The primary endpoint of this study was survival to Day 28 post-inoculation (PI). Anesthesia events were minimized with the use of central venous catheters for periodic blood collection, and temperature and activity were continuously monitored by telemetry. All mock-exposed animals remained healthy for the duration of the study. All 12 MARV-exposed animals (100%) became infected, developed illness, and succumbed on Days 8-10 PI. On Day 4 PI, 11 of the 12 MARV-exposed animals had statistically significant temperature elevations over baseline. Clinically observable signs of MARV disease first appeared on Day 5 PI, when 6 of the 12 animals exhibited reduced responsiveness. Ultimately, systemic inflammation, coagulopathy, and direct cytopathic effects of MARV all contributed to multiorgan dysfunction, organ failure, and death or euthanasia of all MARV-exposed animals. Manifestations of MARV disease, including fever, systemic viremia, lymphocytolysis, coagulopathy, and hepatocellular damage, could be used as triggers for initiation of treatment in future therapeutic efficacy studies.

Real-World Use of Recombinant Von Willebrand Factor in People with Clinically Severe Congenital Von Willebrand Disease: Interim Analysis of Athn 9: A Natural History Study for People with Severe VWD

Background: People with von Willebrand disease (VWD) present with a spectrum of bleeding patterns and clinical symptoms, independent of subtype (Rugeri. Haematologica. 2007; Kalot. Haemophilia. 2021). In certain situations, prophylaxis may be appropriate, particularly when there is recurrent and severe bleeding (Connell, Blood Advances, 2021). There are limited real-world data on the use of recombinant von Willebrand factor (rVWF) in the United States. Aim: To characterize the safety and real-world effectiveness of routine prophylaxis with rVWF in people with clinically severe congenital VWD. Study Design and Methods:This is an interim analysis of a phase 4, longitudinal, prospective, observational cohort study (NCT03853486). Participants with severe VWD types 1, 2, and 3 (≤30% of normal) or “clinically severe VWD” (≤40% of normal with severe bleeding and requiring prophylaxis with factor concentrates) were identified from the ATHNdataset. The American Thrombosis & Hemostasis Network (ATHN) is the steward of the ATHNdataset, a Health Insurance Portability and Accountability Act-compliant, de-identified patient health dataset containing data from individuals with bleeding disorders receiving care through ATHN affiliates who opt in to contribute. Treatment regimens were at the discretion of each participant's respective bleeding disorder provider. Participants are followed for 2 years from the time of enrollment. Safety was measured using definitions from the European Haemophilia Safety Surveillance program. Bleeding events (BEs) were measured by individual bleeding components and calculated per the International Society on Thrombosis and Haemostasis Bleed Assessment Tool and/or the Pictorial Bleeding Assessment Chart. Health-related quality of life measures, including an ATHN9 rVWF substudy form, were used to describe real-world effectiveness of rVWF treatment. Descriptive statistics were used to analyze study outcomes. This study was not designed to detect differences in safety or efficacy between individual treatment products. Interim Results:As of June 16, 2023, 23 participants enrolled in the ATHN9 study were receiving rVWF; 14 participants have been prescribed rVWF for at least 1 full year, 13 of whom received continuous prophylaxis. This abstract reports on those 13 participants in the first year of the study. Mean (SD) age was 42.9 (29.2) years; 69.2% (n=9) of participants were female. Most participants had no comorbidities. As expected, most participants had a family history of VWD (84.6%; n=11) and no documented VWF inhibitors (84.6%; n=11); inhibitor status for the remaining 2 participants was unknown. Baseline VWF and factor VIII measurements were reported for most participants ( Table 1). The majority had type 2 VWD (84.6%; n=11), 92.3% (n=12) had identifiable genetic sequence defects in VWF, and 30.8% (n=4) had an abnormal VWF multimer profile. As dictated by the local investigator, rVWF prophylactic regimens ranged from 36.6 IU/kg once weekly to 57.6 IU/kg every 3 days; 7 (53.8%) participants received 40-60 IU/kg at a frequency of 2-3 times per week. Twenty-one BEs occurred in 5 (38.5%) of the participants receiving rVWF prophylaxis during the first year ( Table 2). Most BEs were spontaneous (61.9%; 13/21), occurring in the nose (n=7), gastrointestinal tract (n=5), or ankle (n=1). The remaining BEs were associated with activity with no known trauma (n=4), trauma (n=2), or unknown cause (n=2). One participant reported 3 rVWF treatment-unrelated adverse events (AEs) of humerus shaft closed fracture, metabolic encephalopathy, and acute exacerbation of chronic obstructive airways disease. When surveyed about their experience with rVWF, participants reported very or extremely satisfied as follows: 76.9% (n=10) with infusion time, 84.6% (n=11) with breakthrough bleed control time, 46.2% (n=6) with number of infusions required for breakthrough bleed control, and 69.2% (n=9) with frequency of achieving bleed control without concomitant hemostatic medication. Discussion:In participants with clinically severe congenital VWD, continuous prophylaxis with rVWF was associated with minimal AEs. Most participants receiving rVWF prophylaxis experienced no BEs during the first year of the study. Most participants expressed overall satisfaction with the use of rVWF.

Initial Results in a Phase 1b Trial of PB-04 in Sickle Cell Disease Demonstrate Fetal Hemoglobin Induction, Additive Activity with Hydroxyurea, and Improved Red Blood Cell Sickling Parameters

Extensive evidence has shown fetal hemoglobin (HbF) is a major modulator of sickle cell disease (SCD) phenotype. Clinical benefit with any increment of HbF was shown in the NIH-sponsored Natural History Study and the Multicenter Study of Hydroxyurea (HU), with mean HbF increases of 3.6% above baseline (BL), to improve survival, reduce painful vaso-occlusive crises, and recently stroke prevention and improved cardiac and neurocognitive function with HU are reported. As some patients do not tolerate optimal HU doses due to cytopenias, additional inducers suitable for combined use are desirable. Proportions of F-cells and HbF-quantity/cell have been cited as important. PB-04, a repurposed drug with a well-known safety profile, is an oral fetal globin stimulant identified in high throughput screening, which suppresses 4 repressors of the HMG gene promoter, ( BCL-11A, LSD-1, HDAC-3, KLF-1). PB-04 induces fetal globin in nonhuman primates, transgenic mice, with additive effect when combined with HU in SCD erythroid progenitors, and was shown to reduce infarcts in multiple organs with preserved splenic function in transgenic sickle mice. An ongoing Phase 1b trial in beta thalassemia intermedia (BTI) ( NCT04432623) of 3 doses (1,3, or 5 mg/kg QD) given 3 (TIW) or 5 times/week (Wk) for 12 or 24 Wks in 18 courses in 10 subjects demonstrates a favorable safety profile, dose-proportional PK with 5 >3 mg/kg doses and 5 >3 doses/Wk, Median fold-increases from baseline (BL) in F-cells of 4.4x BL (range 2.3-7x), 2.8x F-reticulocytes (1.6-14.8x), and 6.5x (range 3-11x) increases in mean fluorescence intensity (MFI, representing amount of HbF/RBC). Mean increases in % HbF were 6.5%. Evaluation of PB-04 has now begun in 7 subjects with SCD, 19-51 yrs; 3 were receiving HU with HbF responses (12-22%). Adverse events, F-cells, F-reticulocytes, MFI (amount of HbF/RBC or HbF/reticulocyte) by FACS and ImageStream Analysis and % HbF are assessed Q 4 wks; flow adhesion of whole blood to VCAM-1 (FA-WB-VCAM) and sickling kinetics are assessed q 12 wks. In 4 subjects on 3 mg/kg QD TIW for 24 wks, changes observed from BL values included mean increases of 6% F-cells and 27% F-reticulocytes (2-fold) . In 3 ongoing subjects receiving 5 mg/kg QD TIW for 12 wks mean changes above BL are currently 13% F-cells, 15% F-reticulocytes; HbF/cell or HbF/reticulocyte have increased up to 10-fold. Mean % HbF has increased above HU effects in 2/3 pts on the second dose by 5-12.6% (mean 8.8%), producing 81-95% F-cells, and 35-38% HbF. Decline in FA-WB-VCAM) was observed ± HU and with both doses in 3 subjects. Correlation of HbF quantity/cell with RBC survival and sickling dynamics is being explored. These early results with not-yet-optimized doses of PB-04 suggest additive activity with HU, producing significant HbF and F-cell levels, and support further PK-optimized studies in patients with SCD.

Congenital Dyserythropoietic Anemia Type II: An Update from the Congenital Dyseryhtropoietic Anemia Registry of North America (CDAR)

Congenital Dyserythropoietic Anemias (CDAs) are a heterogeneous group of rare anemias characterized by ineffective erythropoiesis and hemolysis. The CDA registry in North America (CDAR; NCT02964494) was established to facilitate natural history studies. Participants who do not have a genetic diagnosis are offered family-trio whole genome sequencing (WGS) and elect to provide samples to CDAR biorepository to support collaborative mechanistic studies. CDA type II (CDA-II), the most common CDA type, is an autosomal recessive disease caused by biallelic SEC23Bvariants. CDA-II presents with hemolytic anemia with suboptimal reticulocytosis, iron overload, splenomegaly, and characteristic binucleation in 10-30% of the bone marrow (BM) erythroblasts. Although CDA-II is a recessive disorder, only one SEC23B variant is found in some patients. Here, we present the genetic and clinical data of CDA-II patients enrolled in CDAR so far. As of July 2023, 169 individuals (85 patients; 84 unaffected family members) enrolled in CDAR. Nine have a confirmed CDA-II diagnosis. Six patients have biallelic SEC23B pathogenic variants and 3 have only one variant identified. WGS for the 3 patients with a single variant revealed rare deep-intronic candidate variants. Since SEC23Bis ubiquitously expressed, we studied SEC23B protein levels in patient-derived lymphoblastoid cell lines generated for the CDAR biorepository. Patients with a single SEC23B variant exhibited an expression level comparable to those with biallelic mutations (Figure). The candidate deep intronic variants are currently being investigated for pathogenicity. Seven patients presented with hemolytic anemia during infancy, but the age of diagnosis was delayed by a mean of 12.5 yrs (0.1 to 55 y.o). Blood smears showed mild macrocytosis, poikilocytosis, and several spherocytes congruent with an osmotic gradient ektacytometry resembling mild hereditary spherocytosis. BM examination, when performed, exhibited erythroid hyperplasia, prominent dyserythropoiesis, and binucleation in ≥ 10% of erythroblasts. Anemia severity was variable: 6 patients were transfusion-dependent, 1 received intermittent transfusions, and 2 did not need blood transfusions. Two became transfusion-independent after splenectomy at ages 6 and 7 y.o, and two underwent successful matched-sibling BMT at age 10 and 26 y.o, after adequate chelation (liver iron concentration [LIC]<7 mg/g) Iron overload, disproportionate to transfusions, was present in 6 patients; 5 received iron chelation. All 5 patients with available MRI results had hepatic hemosiderosis (LIC range 3.4 to 21.8 mg/g) and evidence of myocardial hemosiderosis (T2* range 6.3 to 20 ms). Ferritin values were variable (range 58 to 1631.5 ng/ml) and discordant from LIC and T2* measurements. Notably, ferritin underestimated iron overload burden: 2 patients with normal ferritin (58 and 160 ng/mL) had hepatic hemosiderosis (LIC 6.1 and 3.4 mg/g respectively), and patients with severe hepatic and myocardial hemosiderosis (LIC 16.6-21.8 mg/g; T2* 6.3-7.8 ms) had modest ferritin values 1475-1631 ng/mL. Iron overload was present even in a non-transfusion-dependent patient and worsened in a patient post-splenectomy, suggesting a role for ineffective erythropoiesis. To further investigate this possibility, we measured erythroferrone (ERFE), GDF-15, and hepcidin levels in 2 patients so far. ERFE and GDF-15 levels were remarkably higher than controls, and hepcidin-to-ferritin ratios were significantly lower, suggesting that high ERFE, caused by ineffective erythropoiesis, inappropriately suppressed hepcidin for the body's iron levels. In summary, CDA-II diagnosis is often delayed despite early onset of anemia. Genetic testing may expedite the diagnosis. The severity of anemia is variable and there are several patients requiring transfusions. The risk of iron overload, including myocardial overload, is high and appears to be related to ineffective erythropoiesis. While frequency of transfusions may improve post-splenectomy, iron overload is not determined by blood transfusions alone and does not resolve post-splenectomy. Serum ferritin underestimated the burden of tissue iron in CDA-II, suggesting that MRI scans should be employed early. Future studies may identify a role for SEC23B deep intronic variants in CDA-II patients with heterozygous variants.

Regional Genetic Heterogeneity Among Patients with Pyruvate Kinase Deficiency

Background: Pyruvate kinase (PK) deficiency is a rare, congenital hemolytic anemia caused by homozygous or compound heterozygous mutations in the PKLR gene, with a prevalence of 3.2-8.5 individuals per million in Western populations. Over 350 pathogenic variants in the PKLR gene have been reported, with the majority being missense substitutions. Although their frequency differs across regions and populations, the geographic distribution of PKLR variants has not yet been fully investigated. Aim: To evaluate the PKLR genotype distribution by region among patients (pts) with PK deficiency in the merged real-world database of the Peak Registry (NCT03481738) and PK Deficiency Natural History Study (NHS; NCT02053480). Methods: The NHS was a global, longitudinal, observational study that enrolled pts with PK deficiency from 2014-2017 (study completed May 2020). The Peak Registry is an ongoing global registry which was initiated in 2018 to build on the NHS with expanded pt recruitment and geographic reach, broader data collection, and longer pt follow-up. Comparable data from these two studies were integrated to form a merged database providing enlarged sample size and prolonged follow-up from pts who participated in both studies. This analysis included pts with available genotype data from the NHS and Peak Registry, including those who were siblings; a large Amish cohort of pts carrying the homozygous p.R479H variant was excluded to avoid reporting bias. Genotype classifications were aligned between the two studies. Data were extracted from the merged database of NHS and Peak (data cutoff date: 13May2022) and summarized descriptively by region. Regions were defined as: Northern (N) Europe (Denmark, Ireland, Netherlands, UK); Central (C) Europe (Czech Republic, Germany, Switzerland); Southern (S) Europe (France, Italy, Spain, Portugal); Asia (S Korea, Thailand, Turkey); N America (Canada, US). Results: 362 pts were included in the analysis (N Europe, N=59; S Europe, N=62; C Europe, N=51; Asia, N=23; N America, N=167), 97 (27%) of whom were siblings. Most pts (72%) had compound heterozygous PKLR variants (Table). Homozygous mutations were most common among pts from Asia (15/23; 65%) and were least common among pts from S Europe (8/62; 13%). Almost half of pts from N Europe (49%) had a compound heterozygous missense/missense (M/M) genotype, while a similar proportion from S Europe (44%) had a compound heterozygous missense/non-missense (M/NM) genotype. A total of 724 PKLR variants were identified, including 197 unique variants, 26 of which were newly identified. Most were missense mutations (76%), followed by nonsense (10%), splice site (7%), and frameshift (5%) mutations. The majority of mutated alleles in the cohort were single nucleotide variants (90%), followed by small deletions (4%), large deletions (4%), and insertions (2%). The amino acid variant with the highest observed frequency was p.Arg510Gln, both overall (158/724; 22%), and in N Europe (31/118; 26%), C Europe (27/102; 26%), and N America (92/334; 28%), but it was not observed in Asia (0/46; 0%). The second most common variant overall, p.Arg486Trp (67/724; 9%), was the most frequent in S Europe (31/124; 25%). When stratified by genotype, p.Arg510Gln was the most common missense mutation in homozygous pts in each region (40-67%) except in Asia. In Asia, p.Thr157Ala, p.Lys541Asn, and p.Arg194Pro were the most common mutations overall (4/46; 9%), and also the most common missense mutations in homozygous pts (4/28; 14%). One hundred and seventy-four unique variants were observed in compound heterozygotes. In S Europe (27/102; 26%) and Asia (2/10; 20%), p.Arg486Trp was the most frequently observed missense mutation in compound heterozygote pts. Overall and in all regions except for Asia (where it was absent), p.Glu241Ter was the most common non-missense mutation in compound heterozygote pts (32/254; 13%); this was p.Gly540Ter (3/6; 50%) in Asia. Conclusions: This analysis, which used the largest real-world data source for pts with PK deficiency, confirms the genetic heterogeneity of the disease, showing that the mutation frequency in PKLR varies substantially based on geographic distribution and that the identification of novel genetic variants is relatively common in PK deficiency.

Long-Term Outcomes in Chronic Lymphocytic Leukemia Treated with Ibrutinib: 10-Year Follow-up of a Phase 2 Study

Background: Targeted agents have replaced conventional chemotherapy in treatment of chronic lymphocytic leukemia (CLL) with substantially improved outcomes in CLL with TP53 alterations (del17p or TP53 mutations). Whereas fludarabine, cyclophosphamide, and rituximab chemoimmunotherapy (CIT) had a median progression-free survival (mPFS) of 11.2 months and median overall survival (mOS) of 33.1 months as frontline therapy in del17p CLL (Fisher et al. Blood 2016), we previously reported a 6-year PFS of 61% and OS of 79% in CLL with TP53 alterations receiving frontline continuous ibrutinib (Ahn et al. NEJM 2020). In a similar patient subset, the CLL14 study demonstrated a mPFS of 51.9 months and a 5-year OS of 60.0% using fixed-duration venetoclax and obinutuzumab (Al-Sawaf et al. EHA 2023; Al-Sawaf et al. Nat. Comm 2023). Although more effective than CIT, long-term outcomes in the era of targeted therapy are not yet fully defined. With a median follow-up of nearly 10 years, we analyzed efficacy, safety, and depth of response in CLL patients treated with long-term ibrutinib therapy in a phase 2 study (NCT01500733). Methods: Eligible patients had high-risk CLL, defined by TP53 alterations or age ≥65 years-old (N = 84 evaluable), and received ibrutinib 420 mg orally once daily until disease progression or intolerable side effects. Response assessments were performed annually with CT scans up to five years and subsequently with physical exam. Minimal residual disease (MRD) was performed annually with peripheral blood flow cytometry. Undetectable MRD (uMRD) was defined as <1 CLL cell per 10,000 leukocytes. For patients discontinuing the study, long-term outcomes were obtained when possible through a separate natural history study (NCT00923507). Results: As of December 31, 2022, a median follow-up of 113 months and 117 months (reverse Kaplan-Meier) was available for calculation of PFS and OS, respectively. The mPFS for all patients was 85.9 months (Table 1). mPFS was significantly shorter in those with TP53 alterations (67.3 months, N = 53) vs. those without (not reached, N = 31) and in relapsed disease (49 months, N = 32) vs. frontline treatment (108 months, N = 52). The OS at 117 months was 58.5% for all patients, 73.8% for treatment-naïve patients, and 54.1% in patients with TP53 alterations. Among patients with TP53 alterations receiving frontline ibrutinib (N = 34), the mPFS was 81 months with an OS of 69.7% at 117 months. Most patients (82.1%, 69/84) had discontinued ibrutinib at the time of analysis with 15 patients (17.9%) remaining on therapy. 37 (44.0%) patients discontinued ibrutinib for progressive disease including 6 cases with histologic transformation. 27 (32.1%) patients discontinued therapy related to treatment-emergent adverse events (AEs) including 8 cardiac AEs (four cases were grade ≥2 atrial fibrillation), 7 second cancers, 4 infections, 3 cases of dementia (ages 78, 80, and 85), 2 pleural effusions, and 3 other AEs. Five patients (5.9%) withdrew from the study with 4 switching to commercial supply of ibrutinib and one changing to CAR-T therapy. uMRD was observed in 15.4% (13/84) of all patients. The median time to uMRD was 5 years (range: 2 - 10 years). There was no enrichment in these patients for Rai stage ≥3-4, unmutated IGHV, TP53 alteration, prior treatment, or age. Most patients achieving uMRD also had a complete response (CR) to therapy (10/13) and remained progression-free at last follow-up (12/13). The one patient with progressive disease achieved uMRD and CR at 24 months, had detectable MRD at 36 months, and had nodal progression at 60 months. Among the progression-free patients, 8 had subsequent MRD assessments demonstrating sustained uMRD for 1-6 years including one patient who had been off any CLL-directed therapy for 4 years. Conclusions: These results further define the long-term prognosis of patients treated with BTK inhibitors for CLL, most notably with substantial improvements in the OS of patients with TP53 alterations over CIT. Additionally, these results may inform discussions of continuous BTK inhibitor therapy versus fixed-duration venetoclax combinations in frontline therapy of high-risk CLL. In a subset of ibrutinib-treated patients, depth of response increased over multiple years to the point of uMRD suggesting the possibility that such patients might safely discontinue therapy, following paradigms established in patients with chronic myelogenous leukemia.

1573. Viral Blips While on Antiretroviral Therapy are Associated with Virologic Failure

Abstract Background Blips in HIV viral load (VL) while on antiretroviral therapy (ART) are of unclear clinical significance. In this study, we examined the association between blips and virologic failure (VF). Methods We used data from the US Military HIV Natural History Study (NHS) cohort. Included participants were diagnosed with HIV after 2006, had been on ART for ≥ 6months, and had ≥3 VLs recorded and measured using an assay with a lower limit of detection of < 50 copies/mL. VF was defined as two consecutive VLs ≥ 200 copies/mL spanning 90 days or a single VL ≥1000 copies/mL. Blips were defined as VL of 51-999 copies/mL, that were preceded and followed by a VL ≤ 50 copies/mL and were differentiated by magnitude as low-level (VL 51-199 copies/mL) or high-level (200-999 copies/mL). Detectable VLs that did not meet criteria for VF or blips were grouped as low-level viremia (LLV; 51-199 copies/mL), and higher low-level viremia (hLLV; 200-999 copies/mL). Cox proportional hazards models adjusted for demographic characteristics, time updated CD4 counts, ART, and viral load were used. Hazard ratios and 95% confidence intervals are presented. Results A total of 988 participants (median age 34.1 years, 96.7% male, 41.7% African American) were included, of which 55 (5.6%) experienced VF (Table 1). While 191 participants (19.3%) experienced blips, it was the highest VL status in 146 (14.8%) (Table 2). Having blips and low-level viremia was associated with increasing hazard of VF, graded by type and level of viremia (low-level blip 1.86 [1.10 – 3.14]; high-level blip 3.56 [1.13 – 11.18]; LLV 4.10 [3.06-5.51]; hLLV 10.51 [6.28-17.61]. Other factors associated with VF were African American race and higher VL at ART initiation. Whereas higher CD4 counts, and use of integrase strand transfer inhibitors (relative to Non-Nucleoside Reverse Transcriptase inhibitors) were protective (Table 3). Conclusion Detectable viremia, including blips, are associated with an increased risk of VF. The magnitude of the viremia appears important with dose-response-type impact (i.e., viral loads >200 copies/mL having a greater hazard of VF). These findings suggest that individuals with viral blips at a minimum should undergo evaluation for medication adherence and may benefit from more frequent VL monitoring. Disclosures All Authors: No reported disclosures

Respiratory function in LAMA2-related muscular dystrophy and SELENON-related congenital myopathy, a 1.5-year natural history study

IntroductionLAMA2-related muscular dystrophy (LAMA2-MD) and SELENON(SEPN1)-related congenital myopathy (SELENON-RM) are rare neuromuscular diseases with respiratory impairment from a young age. Prospective natural history studies are needed for prevalence estimations, respiratory characterization, optimizing clinical care and selecting outcome measures for trial readiness. MethodsOur prospective 1.5-year natural history study included spirometry (forced vital capacity (FVC); difference between upright and supine vital capacity (dVC)), respiratory muscle strength tests (sniff nasal inspiratory pressure (SNIP)) (age≥5 years), and diaphragm ultrasound (thickness; thickening; echogenicity; all ages). ResultsTwenty-six LAMA2-MD patients (M = 8, median 21 [9; 31] years) and 11 SELENON-RM patients (M = 8, 20 [10; 33] years) were included. At baseline, 17 (85 %) LAMA2-MD (FVC%: 59 % [33; 68]) and all SELENON-RM patients (FVC%: 34 % [31; 46]) had an impaired respiratory function (FVC%<80 %). Nine (35 %) LAMA2-MD and eight (73 %) SELENON-RM patients received mechanical ventilation at baseline, and two additional SELENON-RM patients started during follow-up. Contrarily to LAMA2-MD, SELENON-RM patients had severe diaphragm atrophy (diaphragm thickness z-score: 2.5 [-3.1; −2.1]) and dysfunction (diaphragm thickness ratio: 1.2 [1.0; 1.7]; dVC: 30 % [7.7; 41]). SNIP was low in both neuromuscular diseases and correlated with motor function. In SELENON-RM, respiratory function decreased during follow-up. ConclusionThe majority of LAMA2-MD and all SELENON-RM patients had respiratory impairment. SELENON-RM patients showed lower respiratory function which was progressive, more prevalent mechanical ventilation, and more severe diaphragm atrophy and dysfunction than LAMA2-MD patients. Spirometry (FVC%, dVC) and respiratory muscle strength tests (SNIP) are useful in clinical care and as outcome measure in clinical trials. Clinical trial numberNCT04478981.

The Nature of Ostension

The initiating comparison for this essay is between two images, or shots; one appears in Jessica Sarah Rinland’s Black Pond (2018), and shows two people looking offscreen, surrounded by dense woodland; the other is reprinted and described in Bruno Latour’s essay “Circulating Reference” (1999) and shows three scientists near a border between a savanna and a forest, looking and gesturing in different directions. Rinland and Latour share an ethnographic interest in the material and gestural minutiae of scientific engagement with the non-human world. This essay explores their common interest in pointing, and in ostension more generally, as it emerges in both case studies. Latour provides a rich and suggestive framework through which to understand Black Pond, particularly in its conception of natural-history study as a multi-stage process of mediation, made up of tools and gestures and inferences – rather than the momentary encountering or witnessing more familiar to eco-film aesthetics.

Serum Phosphorus as a Driver of Skeletal Morbidity in Fibrous Dysplasia.

Fibrous dysplasia (FD) results in fractures, pain, and deformities. Abnormal osteoprogenitor cells overproduce FGF23, leading to hyperphosphaturia in most patients and frank hypophosphatemia in a subset. Studies suggest hypophosphatemia is associated with increased FD-related morbidity. However, the relationship between phosphorus and skeletal complications has not been investigated, and the optimal therapeutic target has not been determined. Characterize the impact of serum phosphorus on FD-related morbidity and identify levels associated with increased skeletal complications. Natural history study with 240 subjects at a clinical research center who had ≥1 fasting phosphorus level, determined as age- and sex-adjusted Z-scores. Subjects were categorized based on frank hypophosphatemia (Z-score ≤ -2; n = 48); low-normophosphatemia (> -2 to ≤ -1; n = 66); and high-normophosphatemia (> -1 to ≤ 2; n = 125). Main outcomes were fractures, orthopedic surgeries, and scoliosis. Subjects with frank and low-normophosphatemia had increased fracture and surgery rates vs high-normophosphatemia. The prevalence of moderate to severe scoliosis was similarly higher in the frank and low-normophosphatemia groups. In a subanalysis of patients matched for Skeletal Burden Score ≥35, fracture and surgery rates remained higher in the frank hypophosphatemia group, suggesting association between phosphorus and skeletal complications is not explained by differences in FD burden alone. Both frank hypophosphatemia and low-normophosphatemia are associated with increased FD-related complications. This supports FGF23-mediated hypophosphatemia as a driver of skeletal morbidity, which may impact a larger proportion of the FD/McCune-Albright syndrome population than previously recognized. These findings enable clinicians to identify at-risk patients and will inform development of prospective studies to determine optimal therapeutic targets.

Study methodology and insights from the palovarotene clinical development program in fibrodysplasia ossificans progressiva

BackgroundThe design of clinical trials in rare diseases is often complicated by a lack of real-world translational knowledge. Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic disorder characterized by skeletal malformations and progressive heterotopic ossification (HO). Palovarotene is a selective retinoic acid receptor gamma agonist. Here, we describe the methodology of three studies in the palovarotene clinical development program in FOP and discuss insights that could inform future research, including endpoint suitability and the impact of trial design.MethodsPVO-1A-001 (NCT02322255) was a prospective, protocol-specified, longitudinal FOP natural history study (NHS). PVO-1A-201 (NCT02190747) was a randomized, double-blind, placebo-controlled phase II trial; PVO-1A-202 (NCT02279095) was its open-label extension. Trial designs, including treatment regimens and imaging assessments, were refined between PVO-1A-201 and PVO-‍1A-202, and within PVO-1A-202, based on emerging data as the studies progressed. Palovarotene doses were administered using a flare-up treatment regimen (higher dose for 2/4 weeks, followed by lower dose for 4/≥8 weeks; from flare-up onset), with or without accompanying chronic (daily) treatment. Flare-up and disease progression outcomes were assessed, including incidence and volume of new HO during flare-ups and/or annually, as well as other clinical, patient-reported, and exploratory outcomes. Safety was monitored throughout all studies.ResultsOverall, 114 and 58 individuals with FOP were enrolled in the NHS and phase II trials, respectively. Results of the NHS and PVO-1A-201 were published in 2022; complete results of PVO-1A-202 will be publicly available in due course. Together the studies yielded important information on endpoint suitability, including that low-dose whole-body computed tomography was the optimum imaging modality for assessing HO progression annually and that long study durations are needed to detect substantial changes in functional and patient-reported outcomes.ConclusionsA flexible clinical development program is necessary for underexplored rare diseases to overcome the many challenges faced. Here, the NHS provided a longitudinal evaluation of FOP progression and interventional trials were based on emerging data. The studies described informed the design and endpoints implemented in the phase III MOVE trial (NCT03312634) and provide a foundation for future clinical trial development.Trial registrationNCT02322255 (registered 23/12/2014); NCT02190747 (registered 15/07/2014); NCT02279095 (registered 30/10/2014).

Quantitative Gait and Balance Outcomes for Ataxia Trials: Consensus Recommendations by the Ataxia Global Initiative Working Group on Digital-Motor Biomarkers

AbstractWith disease-modifying drugs on the horizon for degenerative ataxias, ecologically valid, finely granulated, digital health measures are highly warranted to augment clinical and patient-reported outcome measures. Gait and balance disturbances most often present as the first signs of degenerative cerebellar ataxia and are the most reported disabling features in disease progression. Thus, digital gait and balance measures constitute promising and relevant performance outcomes for clinical trials.This narrative review with embedded consensus will describe evidence for the sensitivity of digital gait and balance measures for evaluating ataxia severity and progression, propose a consensus protocol for establishing gait and balance metrics in natural history studies and clinical trials, and discuss relevant issues for their use as performance outcomes.

Clinical study of ferredoxin-reductase-related mitochondriopathy: Genotype-phenotype correlation and proposal of ancestry-based carrier screening in the Mexican population

PurposeFerredoxin reductase (FDXR) is a flavoprotein that functions in both iron sulfur cluster biogenesis and steroid biosynthesis pathways in the mitochondria. Not surprisingly, loss of FDXR function causes severe mitochondrial diseases in humans. Although several FDXR-related mitochondriopathy (FRM) cohorts have been reported in the literature, further characterization of the natural history of FRM is warranted. MethodsTo better understand the spectrum of FRM, a natural history study of FRM was performed. New cases were added to previously reported FRM cases for analysis (n = 62 cases). ResultsOptic atrophy, movement disorder, and developmental delay were frequent findings. Mortality is high, with 18% of patients, often infants, passing from complications. Notably, 25% of cases were homozygous or compound heterozygous for the previously reported p.Arg386Trp “hotspot” variant. Of the obtained ancestry, all but 1 individual heterozygous for the p.Arg386Trp variant was Hispanic, with many reporting Mexican heritage. Utilizing recent large-scale genome sequencing surveys, the carrier frequency of the p.Arg386Trp variant was estimated as 1 of 185 in the Mexican population. ConclusionGiven the high mortality of FRM and carrier frequency of the common variant, consideration of a new approach for population carrier screening and development of therapeutics for affected individuals is needed.

Neurological manifestations in PMM2-congenital disorders of glycosylation (PMM2-CDG): Insights into clinico-radiological characteristics, recommendations for follow-up, and future directions

PurposeIn the absence of prospective data on neurological symptoms, disease outcome, or guidelines for system specific management in phosphomannomutase 2-congenital disorders of glycosylation (PMM2-CDG), we aimed to collect and review natural history data. MethodsFifty-one molecularly confirmed individuals with PMM2-CDG enrolled in the Frontiers of Congenital Disorders of Glycosylation natural history study were reviewed. In addition, we prospectively reviewed a smaller cohort of these individuals with PMM2-CDG on off-label acetazolamide treatment. ResultsMean age at diagnosis was 28.04 months. Developmental delay is a constant phenotype. Neurological manifestation included ataxia (90.2%), myopathy (82.4%), seizures (56.9%), neuropathy (52.9%), microcephaly (19.1%), extrapyramidal symptoms (27.5%), stroke-like episodes (SLE) (15.7%), and spasticity (13.7%). Progressive cerebellar atrophy is the characteristic neuroimaging finding. Additionally, supratentorial white matter changes were noted in adult age. No correlation was observed between the seizure severity and SLE risk, although all patients with SLE have had seizures in the past. “Off-label” acetazolamide therapy in a smaller sub-cohort resulted in improvement in speech fluency but did not show statistically significant improvement in objective ataxia scores. ConclusionClinical and radiological findings suggest both neurodevelopmental and neurodegenerative pathophysiology. Seizures may manifest at any age and are responsive to levetiracetam monotherapy in most cases. Febrile seizure is the most common trigger for SLEs. Acetazolamide is well tolerated.

Incidence of flow-limiting coronary artery stenoses in patients with diabetes - a coronary angiography natural history study

Abstract Background Diabetes is an established risk factor for the development of coronary atherosclerosis. We sought to assess the association between diabetes and the incidence of coronary artery atherosclerosis progression on coronary angiography. Methods Using the Swedish Coronary Angiography and Angioplasty Registry (SCAAR), we included all coronary artery segments with mild to no atherosclerosis defined as &amp;lt;50% luminal obstruction in patients undergoing a first-time coronary angiography in Sweden between 1989 and 2017. Patients with two or more vessel disease were excluded as were patients with a previous history of coronary artery disease. In patients with one vessel disease, the diseased vessel including all its branches were excluded. Patients were followed for 15 years until a clinically indicated re-angiography was done, death occurred or end of follow-up (April 2018). The primary outcome was plaque progression to flow-limiting coronary artery stenosis defined as ≥50% luminal obstruction on repeat angiography assessed using epidemiological tables, Kaplan Meier event rates, and Cox proportional hazard models. The importance of selected risk factors (smoking, hypertension, hyperlipidemia, and established coronary artery disease) was assessed. Results A total of 2 661 245 coronary segments in 248 736 patients were included in the study. Diabetes was present in 30 533 patients and 320 815 coronary artery segments. Kaplan-Meier event rates and incidence rates (IR) per 1000 segment-years were higher in patients with diabetes (5.5%, IR 2.78 [95% CI 2.70–2.85] vs. 3.0%, 1.44 [1.42–1.46]) resulting in an almost two-folded hazard ratio (HR) of plaque progression (HR 1.93 [95% CI 1.87– 2.00]). The anatomical distribution of plaque progression was similar between the two cohorts on all levels of analysis (coronary artery level, main artery and branches level, and coronary segment level artery). Diabetic patients with established coronary artery disease had a significantly higher risk of future events compared to those without clinically significant coronary artery disease. Conclusions Diabetes was associated with an almost twofold higher incidence rate of plaque progression but did not appear to alter the anatomical location of plaque development compared to the absence of diabetes. Once coronary artery disease is established, the rate of atherosclerotic events accelerates. Therefore, adopting aggressive primary prevention strategies is crucial to reduce the risk of adverse outcomes in diabetic patients.Event rates and anatomical distributionProgression of stenoses by risk factor

Abstract 15278: Cardiac Assessments and Manifestations Among Individuals With Long-Chain Fatty Acid Oxidation Disorders: A Retrospective Claims Database Analysis

Introduction: Long-chain fatty acid oxidation disorders (LC-FAOD) are inherited autosomal recessive defects resulting in enzyme deficiencies in the carnitine cycle or the mitochondrial β-oxidation pathway leading to deficiencies in mitochondrial energy metabolism. Cardiac manifestations, specifically cardiomyopathy and arrhythmias, are common and are leading causes of mortality in individuals with LC-FAOD. Goal: The goal of this study was to better understand cardiac manifestations and long-term outcomes in this group of disorders. Methods: The analysis was done using IQVIA PharMetrics® claims data. Individuals with confirmed LC-FAOD were identified and a non-LC-FAOD comparators group was created using 1:20 exact matching on age, gender, payer type, and enrollment start year. Cardiac-related complications were examined using ICD-10 diagnosis codes at any billing position during the study period. Cardiac diagnoses and assessments were evaluated using Current Procedural Terminology (CPT®) codes in a non-inpatient setting. Results: A total of 337 pediatric (peds) and 86 adult individuals with LC-FAOD were included in the study. Cardiomyopathy (peds: 8.0%, adults: 10.5%) and arrhythmias (peds: 8.9%, adults: 14.0%) were common among individuals with LC-FAOD and were significantly higher than comparators. LC-FAOD adults had significantly more cardiac conditions compared with pediatric patients and comparators. The other most common cardiac conditions among adults with LC-FAOD were chronic ischemic heart disease (18.6%), non-rheumatic mitral or tricuspid valve disorders (11.6% and 12.8%, respectively), heart failure (10.5%), atrioventricular and left bundle-branch block (7.0%), and cardiomegaly (5.1%). Individuals with LC-FAOD had significantly more cardiac related procedures than comparators. EKGs (peds: 35.9%; adults: 77.9%) and echocardiograms (peds: 44.8%; adults: 53.5%) were common among individuals with LC-FAOD. Conclusions: This analysis shows the importance of assessing the cardiac status of individuals with LC-FAOD. More analyses and natural history studies are needed to inform healthcare providers of cardiac risks associated with LC-FAOD and reduce mortality in these individuals.