Asymptomatic Carriers Research Articles

Heart Disease in Mothers of Children with Duchenne Muscular Dystrophy.

Female carriers of Duchenne Muscular Dystrophy (DMD) carry a heterozygous pathogenic variant in the dystrophin gene and can transmit pathogenic variants to their offspring. DMD is an X-linked recessive disease that affects up to 19.8 in every 100,000 male births. Those carriers with symptoms can be referred to as women with dystrophinopathy. Even among asymptomatic carriers, cardiac involvement can be verified in between 2.5% and 75% through echocardiography. The most commonly affected wall of the left ventricle is the inferolateral, with myocardial fibrosis detected by cardiac nuclear resonance. Therefore, screening is recommended for these women carriers due to the risk of cardiomyopathy. There is a lack of longitudinal studies on the evolution of these carriers. In this article, data on clinical presentation, cardiac assessment for female patients with dystrophinopathy and DMD carriers, and approaches for these patients are discussed.

Usefulness of scintigraphy with [99mTc]Tc-DPD for the detection of transthyretin cardiac amyloidosis. Reference centre experience in an endemic area

Abstract Background Cardiac amyloidosis (CA) is an infiltrative disorder caused by protein deposition, being transthyretin amyloidosis (ATTR) and primary amyloidosis (AL) the most common forms of CA. ATTR can occur in a hereditary form (ATTRv) or wild-type (ATTRwt). Our area is endemic for ATTRv due to the Val30Met mutation. Purpose To analyse the usefulness of scintigraphy with [99mTc]Tc-DPD (DPD-CS) in an endemic area and its relationship with the diagnostic of CA. Methods We conduct a retrospective study (04/2013-12/2022) of DPD-CS performed for suspected/screening of CA. Our acquisition protocol consists of performing planar images after 3h p.i.(anterior, left anterior oblique and left lateral) +/- SPECT/CT. The assessment of myocardial uptake was evaluated using the Perugini scale (PS: 0-3), considering 2 and 3 as positive scans. DPD-CS results were classified based on the suspicion of CA, according to the 2021 ESC guidelines (we considered cardiomyopathy if: left ventricle hypertrophy ≥12 mm + ≥3 typical signs/symptoms), as well as according to their final diagnosis: ATTRv, asymptomatic carriers, ATTRwt, AL, AA and other non-amyloid (NA) causes. Clinical findings were correlated with the results of the DPD-CS. Results 509 DPD-CS were performed in 478 patients (median age:73 years [22-95], 62% men). Median follow-up: 4.17 years. 127/478 patients were classified with cardiomyopathy (131/509 DPD-CS) and 351/478 without cardiomyopathy (378/509 DPD-CS). 115/509 positive DPD-CS (PS-2: 17, PS-3: 98): 113 had cardiomyopathy (55 ATTRv, 60 ATTRwt) and 2 without cardiomyopathy (1 ATTRv, 1 asymptomatic carrier). These latter two patients developed cardiomyopathy during the follow-up. 394/509 negative DPD-CS (PS 0: 387, PS 1: 7): 18 with cardiomyopathy (1 ATTRv, 1 carrier, 3 AL and 13 NA) and 376 without cardiomyopathy (30 asymptomatic carriers, 88 ATTRv, 2 AA, 9 AL and 247 NA). One patient with cardiomyopathy and ATTRv had initial negative DPD-CS, but became positive DPD-CS on follow-up. All ATTRv without cardiomyopathy presented polyneuropathy. Final diagnoses (according to DPD-CS number): 143 ATTRv (140 Val30Met, 2 Val122Ile, 1 Glu495Gln), 32 carriers (29 Val30Met, 2 Val122Ile, 1 His51Asn), 61 ATTRwt,12 AL, 2 AA and 259 NA. The analysis obtained after correlating the results of the DPD-CS regarding the presence of cardiomyopathy was: sensitivity 86.25%, specificity 99.47%, PPV 98.26% and NPV 95.43%. Conclusion Our study reaffirms the usefulness of DPD-CS in the non-invasive diagnosis of transthyretin CA. DPD-CS has an additional value in endemic areas for the early detection of CA in asymptomatic patients.

Impact of high intensity and long duration exercise in genetic arrhythmogenic left ventricular cardiomyopathy

Abstract Background Arrhythmogenic left ventricular (LV) cardiomyopathy (ALVC) is a genetic disease associating extensive LV myocardial fibrosis with or without dysfunction and no or mild right ventricle (RV) involvement, at risk of life-threatening ventricular arrhythmias (VA). While high intensity (HI) and long duration (LD) exercise has been identified as a precipitating factor of RV dysfunction and VA in arrhythmogenic RV cardiomyopathy including in asymptomatic genetic variant carriers, the impact of exercise on disease phenotype and risk is not known in ALVC. Objective To study the relationship between practicing HI and LD exercise and the risk of developing an ALVC phenotype and its severity. Methods In a monocentric retrospective observational study, patients with a pathogenic variant in common ALVC genes (DSP, FLNC, DES, PLN, RBM20, TMEM43), including asymptomatic carriers without ALVC phenotype, were interviewed about their physical practice from age 7 to the time of genetic or disease diagnosis. Intensity and weekly duration of each activity were reported. HI and LD exercise were defined as having practiced at least 1 sport with an intensity ≥ 6 METs and ≥ 2.5 hours/week respectively. We studied the association of HI and LD exercise practice with the risk of ALVC phenotype occurrence and its severity, derived from clinical, ECG and imaging data. Results 114 out of 128 eligible patients answered the questionnaire and were included (85 (74.6%) with a DSP variant, 22 FLNC (19.3%), 6 DES (5.3%), 1 RBM20 (0.9%)). 35 were probands (31%) and 79 relatives (69%) among 46 families. 31 (27%) had no ALVC phenotype at the time of genetic diagnosis. Mean age at diagnosis was 41±18. 62 (54%) patients were women. 97 (85%) had practiced at least one sport, among which 81 (83.5%) at HI and 79 (81.4%) of LD. Median lifetime exercise dose was 18.5 MET.h/week. There were no differences in HI and LD exercise practice between probands and relatives (74.3% vs 69.6%, p=0.6 and 74.3% vs 67.1%, p=0.4 respectively), as well as between patients with and patients without ALVC phenotype at the time of diagnosis (74.7% vs 61.3%, p=0.2 and 72.3% vs 61.3%, p=0.3 respectively). Phenotypic features at diagnosis did not differ between patients with and without HI and LD practice (Table 1). Multivariate analysis adjusted on age and gender showed that HI and LD exercise were not significantly associated with an increased risk of developing an ALVC phenotype (Odds Ratio [95% confidence interval] for age, gender, HI and LD exercise were 1.03 [1.01-1.06] (p=0.013), 1.41 [0.58 ; 3.47] (p=0.45), 2.15 [0.63 ; 7.27] (p=0.22) and 1.17 [0.35 ; 3.87] (p=0.79) respectively). Phenotypic features at diagnosis did not differ across observed quartiles of lifetime exercise dose (Table 2). Conclusion Practicing HI and LD exercise was not associated with an increased risk of developing an ALVC phenotype and its severity at the time of diagnosis in genetic ALVC variant carriers.

Effect of trimetazidine dihydrochloride therapy on myocardial external efficiency in preclinical individuals with an HCM sarcomeric gene mutation

Abstract Background Hypertrophic cardiomyopathy (HCM) is frequently caused by pathogenic gene variants, i.e. mutations in genes encoding sarcomere proteins. Previous studies have shown that preclinical asymptomatic individuals with a heterozygous sarcomere mutation have decreased myocardial external efficiency (MEE), which is thought to be a key pathomechanism in the onset and progression of HCM. Purpose In the ENERGY trial, preclinical individuals with an HCM sarcomere gene mutation without hypertrophy were treated with the metabolic anti-anginal drug trimetazidine (TMZ) to determine whether the reduced MEE can be corrected at an early pre-hypertrophic disease stage. Methods 40 MYBPC3 and MYH7 asymptomatic mutation carriers without hypertrophy were treated for eight weeks with TMZ or placebo in a double-blind randomized study design. Directly before and after treatment, study participants underwent an [11C]-acetate PET/CT-scan and cardiac magnetic resonance imaging to measure MEE. A cardio-pulmonary exercise test was performed to measure the influence of TMZ on exercise parameters. Results Eight weeks of treatment with TMZ 20mg three times daily did not significantly alter MEE compared to placebo. The mean MEE changed from 30.3±3.8 percent to 29.8±4.3 percent in the placebo group and from 30.1±4 percent to 29.1±4 percent in the TMZ group. After adjustment for baseline, the TMZ group did not have a significantly different MEE (95% CI, -2.863 to 1.986, P=0.68) compared to placebo. Exercise parameters VO2max and respiratory exchange ratio were not significantly altered by treatment with TMZ. Conclusion The ENERGY trial is the first proof-of-concept randomized controlled trial with well-matched (age, sex, mutation) groups to test the hypothesis that TMZ improves MEE at a preclinical disease stage. We conclude that metabolic therapy does not correct reduced MEE in an early disease stage of HCM.methodsprimary outcome

Nontargeted urine metabolomic analysis of acute intermittent porphyria reveals novel interactions between bile acids and heme metabolism: New promising biomarkers for the long-term management of patients.

Acute intermittent porphyria is an inherited error of heme synthesis. The underlying pathophysiology, involving mainly hepatic heme synthesis, is poorly understood despite its occurrence, and the severity of acute porphyria attack is still difficult to control. A better understanding of the interactions between heme synthesis and global metabolism would improve the management of AIP patients. An untargeted metabolomic analysis was performed on the urine of 114 patients with overt AIP and asymptomatic carriers using liquid chromatography coupled to high-resolution mass spectrometry. The collected data were analyzed by combining univariate and multivariate analyses. A total of 239 metabolites were annotated in urine samples by matching chromatographic and mass spectral characteristics with those from our chemical library. Twenty-six metabolites, including porphyrin precursors, intermediates of tryptophan or glycine metabolism and, unexpectedly, bile acids, showed significant concentration differences between the phenotypic groups. Dysregulation of bile acid metabolism was confirmed by targeted quantitative analysis, which revealed an imbalance in favor of hydrophobic bile acids associated with changes in conjugation, which was more pronounced in the severe phenotype. Using a random forest model, the cholic acid/chenodeoxycholic acid ratio enables the differential classification of severe patients from other patients with a diagnostic accuracy of 84%. The analysis of urine samples revealed significant modifications in the metabolome of AIP patients. Alteration in bile acids provides new insights into the pathophysiology of chronic complications, such as primary liver cancer, while also providing new biomarker candidates for predicting the most severe phenotypes.

An Acinetobacter baumannii nasal carriage isolate recovered from an asymptomatic patient in Vietnam is extensively antibiotic resistant and produces a rare K71 type capsule.

The majority of Acinetobacter baumannii genomes sequenced and analyzed to develop an understanding of extensively drug-resistant (XDR) isolates belong to the globally disseminated CC2 clonal complex. While XDR isolates belonging to rarer lineages are often unexplored, detailed analyses could provide novel insights into the spread of resistance, as well as cell surface features such as the CPS that determine the specificity of non-antibiotic therapeutics required to treat XDR infections that resist antimicrobial chemotherapy. Here, we describe the properties of an XDR asymptomatic nasal carriage isolate recovered in Vietnam that belongs to ST142, a rarely encountered sequence type. We report the resistance profile and correlate this with detected resistance determinants. We also solve the structure of the CPS and reveal its relationship with CPS produced by other A. baumannii isolates.

Host cytokine genetic polymorphisms in a selected population of persons living with hepatitis B virus infection in the central region of Ghana.

Hepatitis B virus (HBV) infection is a public health concern in resource limited settings like Ghana. Over the past decades, it is noted that the natural course of HBV in persons infected are taking a worse turn leading to liver cirrhosis and cancer. The outcome of HBV infection is influenced by viral and host factors including genetics. Cytokine variations affect virus survival and progression and may even influence associated complications. Cytokines such as tumor necrosis factor alpha (TNF-α), interleukins (IL-4, IL-6, IL-8, IL-10, IL-18), interferon gamma (IFN)-γ, and tumor growth factor-beta (TGF-β) have key roles in HBV infection and modulation. In this study, polymorphisms occurring in five cytokines were analysed to understand how they can influence prognosis of HBV infection. The study is a single centre cross-sectional study involving 227 participants made up of HBV infected participants and HBV-negative controls. Recruitment was from March 2021 to April 2022. Blood samples were taken for full blood count, HBV antigen profile, liver function tests, HBV DNA quantification and cytokine genotyping. FIB score was calculated using available tools. Statistical analysis was undertaken with p < 0.05 set as statistically significant. The 20-39-year-old group formed majority of the HBV infected participants with 60% of all participants being classified as healthy HBsAg carriers. IL2 rs1479920 GG carriers ((1258.93; 0.00-5011.87) IU/mL had reduced HBV DNA in comparison to IL2 rs1479920 AA ((5011.87; 2113.49-5956.62) /AG (3548.13; 0.00-6309.57) IU/mL carriers. TNF-α rs1800629 AA carriers (1258.93; 0.00-3981.07) IU/mL had a reduction in HBV DNA levels in comparison to TNF-α rs1800629 GG carriers (1584.89; 0.00-5011.87) IU/mL. The results of univariate (OR = 0.08, 0.00-0.93; p = 0.043) and multivariate (OR = 0.02, 0.00-0.67; p = 0.029) analysis, showed that carrying TNF-α rs1800629 AA genotype reduce susceptibility to high FIB score compared with GG genotypes. In univariate analysis, subjects aged 20-39years (OR = 5.00, 1.13-6.10; p = 0.034) and 40-59years (OR = 41.99, 3.74-47.21; p = 0.0002) were more susceptible to high FIB score compared to subjects aged 1-19years. Being female (OR = 2.42, 1.03-5.71; p = 0.043) in the univariate models showed higher odds of having high levels of HBV DNA in the multivariate model. There was a reduced likelihood of herbal medicine usage influencing HBV DNA levels significantly (OR = 0.29, 0.10-0.86; p = 0.025). In conclusion, variations in IL2 rs1479920 GG and IL2 rs1479921 AA could offer protective effects by reducing HBV DNA. TNF-α rs179924CT may also cause elevation in HBV DNA levels whiles TNF-α -308A/G, showed a potential protective effect on liver scarring in HBV infected participants. It is therefore important to take a further look at such variations for understanding of HBV modulation in the Ghanaian population.

Adipose-Derived Stem Cells as Carrier of Pro-Apoptotic Oncolytic Myxoma Virus: To Cross the Blood–Brain Barrier and Treat Murine Glioma

Treatment of glioblastoma is ineffective. Myx-M011L-KO/EGFP, a myxoma virus actively inducing apoptosis in BTICs linked to recurrence, offers innovative treatment. We loaded this construct into adipose-derived stem cells (ADSCs) to mitigate antiviral host responses and enable systemic delivery. The apoptotic and cytotoxic effects of the construct were studied using murine and human glioblastoma cell lines. Before implementing systemic delivery, we delivered the construct locally using ADSC to verify elimination of orthotopic murine glioma lesions. vMyx-M011L-KO/EGFP was cytotoxic to a murine cell line, preventing effective virus multiplication. In three human glioma cell lines, viral replication did occur, coupled with cell killing. The knock-out construct induced apoptotic cell death in these cultures. ADSCs infected ex vivo were shown to be sufficiently migratory to assure transfer of the therapeutic cargo to murine glioma lesions. Virus-loaded ADSCs applied to the artificial blood–brain barrier (BBB) yielded viral infection of glioma cells grown distally in the wells. Two rounds of local administration of this therapeutic platform starting 6 days post tumor implantation slowed down growth of orthotopic lesions and improved survival (total recovery &lt; 20%). ADSCs infected ex vivo with vMyx-M011L-KO/EGFP show promise as a therapeutic tool in systemic elimination of glioma lesions.

Mpox – Clado 1B: Uma revisão e avanços do novo alerta global de saúde pública

Scientific interest in mpox has grown significantly in recent decades, especially due to the increase in the incidence of human cases and the potential threat that the virus poses to global public health. This article aims to increase access to information about this disease and the behavior of the Clade 1B mutation in affecting the immune system and representing a first-degree threat to carriers of the Human Immunodeficiency Virus (HIV) in Portuguese, since the main information is still are published in a foreign language. The information is recent and so is the global alert issued by the World Health Organization. It is necessary to democratize access to scientific information about a possible second global pandemic in the making.

Abstract B058: Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients

Abstract Lynch Syndrome (LS) is the most common hereditary cancer syndrome, caused by germline mutations in one of the four DNA mismatch repair (MMR) genes. LS patients have a high risk to develop microsatellite instable (MSI) colorectal cancers. Tumors developed by LS carriers display high levels of microsatellite instability, which leads to the accumulation of large numbers of mutations, among which frameshift insertion/deletions (indels) within microsatellite (MS) loci are very common and shared among different tumors. When indels occur in coding genes they give rise to frameshift peptides (FSPs) with a very high potential to act as safe and potent neoantigens for a vaccine. NOUS-209 is a genetic vaccine encoding 209 neoantigens, shared across sporadic and hereditary MSI tumors, developed for interception and treatment of MSI tumors. Phase 1b trial evaluating NOUS-209 monotherapy in healthy LS carriers showed the induction of a potent and broad immune response. Here, we characterize indels encoding FSPs in a cohort of 50 incident MSI CRC from LS patients detected during routine screening (38 primary tumors; 22 metachronous tumors) by whole Exomeseq NGS. Overall, primary and metachronous tumors have a similar number of indels in coding genes. The repertoire of detected indels is only partially shared (27%) between the two categories of tumors. The 209 indels selected for the NOUS-209 vaccine are instead highly shared (95%) between primary and metachronous tumors. Moreover, the analysis of 8 patients for which both the primary and the metachronous tumor were available confirmed the presence of the 209 mutations both in the first and the second tumor. Therefore, the NOUS 209 vaccine has the potential to prevent tumor occurrence both in previvors and survivors by inducing a broad T cell immune response against recurrent FSP. Citation Format: Lorenzo De Marco, Elisa Micarelli, Joni Panula, Anna Morena D'Alise, Guido Leoni, Kalle E. Hokkanen, Eija Hämäläinen, Jukka-Pekka Mecklin, Elisa Scarselli, Toni Seppälä. Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B058.

Hereditary Transthyretin Amyloidosis Polyneuropathy.

In the last decade, we have witnessed dramatic improvements in the diagnosis, workup, management, and monitoring of patients with hereditary transthyretin amyloidosis (ATTRv). Updated imaging techniques (e.g., 99mTc-PYP scan) are increasingly being used in place of tissue biopsies for confirmation of disease. Novel treatments now include antisense oligonucleotide and RNA interference drugs, whereas new applications such as CRISPR and amyloid antibodies are being studied for potential use in the future. These treatments have dramatically improved quality of life and increased survival in patients with ATTRv. Despite these breakthroughs, many challenges remain. Some of these challenges include early recognition and diagnosis of ATTRv, monitoring and initiation of treatment in asymptomatic or paucisymptomatic carriers, adequate treatment in people with mixed phenotype (i.e., cardiac and neurological), and the emergence of new phenotypes in people living longer with the disease (i.e., central nervous system and ocular complications). Research in those areas of deficit is ongoing, and in the future, we may have preventive therapies, better biomarkers, more efficient therapies for organs that we cannot currently target, and enhanced diagnostic techniques with the help of novel imaging techniques and artificial intelligence. In this review, we will summarize the current knowledge about polyneuropathy related to ATTRv and its management, discuss methods to improve early diagnosis and monitoring, and discuss emerging trends.

A Rare Case of Homozygous Hemoglobin G-Philadelphia &amp; Alpha Thalassemia

Abstract Introduction/Objective Hemoglobin (Hb) G-Philadelphia (GPh) is an alpha chain gene variant caused by a missense mutation resulting in a change from Glu to Asp at position 68. This change leads to alterations in the Hb structure and oxygen affinity. The mutation is inherited in an autosomal codominant pattern allowing for an asymptomatic carrier state. While the most common alpha chain variant, GPh heterozygosity is still infrequent, estimated at 1:5000 in African Americans. In African Americans, GPh is frequently linked to an alpha thalassemia deletion. On its own it is considered a benign variant that does not result in significant health issues. Homozygous HbGPh frequency is estimated at 1 in 25 million. Methods/Case Report A postpartum woman in her 4th decade of life was found to have a Hb of 10.8 and a mean corpuscular volume of 74. Initial work up included Hb electrophoresis that quantified HbA at 0%, Hb F at 0%, HbA2 at 0%, and 2 Hb variants representing 96.1% and 3.8% of the total globin. The major Hb variant migrated in the D or G position by alkaline and acid gel Hb electrophoresis. The minor variant was consistent with HbG2. Due to this abnormal Hb electrophoresis, a sample was sent out for a Hb evaluation reflexive cascade (HERC). HERC analysis by high-performance liquid chromatography and capillary gel electrophoresis found 99.9% of Hb consistent with the alpha chain variant HbG. Analysis of the alpha globin gene region revealed 2 copies of an alpha globin gene deletion that was interpreted as alpha-thal trait (-a/-a). This result is consistent with homozygous alpha-thal-2 and homozygous HbGPh (alpha^G/thal + alpha^G/thal). Results (if a Case Study enter NA) NA Conclusion Alpha^G/thal + alpha^G/thal presents a unique and complex challenge for diagnosis due to its rarity and because HbG2 is not always visualized by alkaline gel electrophoresis. The presence of a Hb G or D variant, a HbG2 variant, and the lack of both HbA and HbA2 are key electrophoretic findings. Clinically, alpha^G/thal + alpha^G/thal behaves essentially like a homozygous alpha-thal-2 trait with persistent microcytosis and erythrocytosis. Thus, co- inheritance of the alpha-thal trait will be suggested by a thalassemic complete blood count pattern.

Serotype independent protection induced by a vaccine based on the IgM protease of Streptococcus suis and proposal for a new immunity-based classification system

The IgM protease (IdeSsuis gene; Gene ID 8153996) of Streptococcus suis is a putative virulence factor that has been shown to be a protective vaccine antigen for pigs (Seele et al. Vaccine 33:2207–12, 2015). To assess its potential as a cross-protective antigen, the amino acid variability among prevalent clinical isolates in various regions and among various serotypes was investigated. Multi-sequence alignment of full-length amino acid sequences of S. suis IgM protease, available in the public domain (status Jan-2022) supplemented with in-house sequences, i.e. a total of 1999 sequences, revealed that the IgM protease of S. suis clusters into three main evolutionary distinct branches: groups A, B and C. Group A, 82% of the sequences in the database, was associated with clinical isolates of various serotypes. Group B, 6% of the strains in the database, was associated with clinical isolates mainly in the EU and mainly belonging to serotype (st) 9. Group C, 12% of the strains in the database, was largely associated with healthy carrier isolates, i.e. nose or tonsil isolates of various serotypes but in particular with st9 and un-typable strains. Within the groups A, B and C, high levels of amino acid identity were observed (> 75%), whereas between groups A and B, the percentage amino acid identity was approximately 30% and between groups A and C approximately 55%. Experimental Escherichia coli expressed recombinant subunit vaccines based on the IgM protease group A sequence of st1 strain B10-99, st2 strain 10 or st7 strain 14009-1, induced serotype independent protection in pigs against challenge with all group A strains tested, i.e. strains of different parts of the phylogenetic tree and of different serotypes including st1, 2, 9 and 14. Protection was observed after vaccination of piglets at 3 and 5 weeks of age and subsequent challenge at 7 weeks but also after vaccination of gilts at 6 and 2 weeks before anticipated parturition and challenge of the offspring up to at least 8 weeks of age. No protection was observed against challenge with st9 strain SZ2000-6264 having group B IgM protease. A recombinant subunit vaccine based on the group B IgM protease sequence, also did not protect against challenge with the homologous group B st9 challenge strain. The results indicate that a vaccine based on a group A IgM protease induces protection against all S. suis strains that express the group A IgM protease. Depending on the geographical region such a vaccine is expected to protect against 60–100% of the virulent S. suis strains. Since the novel proposed IgM protease classification is highly relevant, a PCR was developed and validated, to be able to classify clinical isolates into IgM protease groups A, B and C and predict the cross-protection that can be expected from a group A based IgM protease vaccine.

Carrier identification and genetic counselling

The identification of carriers, so-called healthy carriers, of hereditary diseases or those with a significant hereditary component is assuming considerable importance at this stage of health care, which is increasingly turning its attention to preventive medicine. This type of operation has numerous implications, of a technical, social, psychological and moral nature, some of which represent a relatively new experience for the doctor or healthcare facility.

Neurofilament light chain as a biomarker for hereditary ATTR amyloidosis − correlation between neurofilament light chain and nerve conduction study

Background Neurofilament light chain (NfL) is a biomarker of neuronal injury in hereditary ATTR (ATTRv) amyloidosis. However, the correlation between NfL and nerve conduction study (NCS), the standard test for ATTRv neuropathy, has not been investigated. Objective Elucidate the correlation between NfL and NCS parameters. Methods 227 serum NfL measurements were performed in 45 ATTRv patients, 5 asymptomatic carriers, and 12 controls. Among them, 177 simultaneous analyses of NCS and NfL were conducted in 45 ATTRv patients. Results NfL levels of symptomatic patients were significantly higher than those of asymptomatic carriers and controls. Serum NfL levels were correlated with NCS parameters, especially compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes, indicators of axonal damage. CMAP and/or SNAP amplitudes were undetectable in 9 patients (no-amplitude group) due to advanced neuropathy. NfL levels in the no-amplitude group were significantly higher than those in patients with detectable CMAP/SNAP. NfL levels significantly decreased with patisiran, although no significant changes were observed in CMAP and SNAP. Conclusions NfL levels are found to be correlated with CMAP/SNAP amplitudes. Compared with NCS, NfL can be a more sensitive biomarker for detecting treatment response and active nerve damage even in patients with advanced neuropathy.

RpoS activates formation of Salmonella Typhi biofilms and drives persistence in the gall bladder.

The development of strategies for targeting the asymptomatic carriage of Salmonella Typhi in chronic typhoid patients has suffered owing to our basic lack of understanding of the molecular mechanisms that enable the formation of S. Typhi biofilms. Traditionally, studies have relied on cholesterol-attached biofilms formed by a closely related serovar, Typhimurium, to mimic multicellular Typhi communities formed on human gallstones. In long-term infections, S. Typhi adopts the biofilm lifestyle to persist in vivo and survive in the carrier state, ultimately leading to the spread of infections via the fecal-oral route of transmission. In the present work, we studied S. Typhi biofilms directly, applied targeted as well as genome-wide genetic approaches to uncover unique biofilm components that do not conform to the CsgD-dependent pathway established in S. Typhimurium. We undertook a genome-wide Tn5 mutation screen in H58, a clinically relevant multidrug resistance strain of S. Typhi, in gallstone-mimicking conditions. We generated New Generation Sequencing libraries based on the ClickSeq technology to identify the key regulators, IraP and RpoS, and the matrix components Sth fimbriae, Vi capsule and lipopolysaccharide. We discovered that the starvation sigma factor, RpoS, was required for the transcriptional activation of matrix-encoding genes in vitro, and for S. Typhi colonization in persistent infections in vivo, using a heterologous fish larval model. An rpoS null mutant failed to colonize the gall bladder in chronic zebrafish infections. Overall, our work uncovered a novel RpoS-driven, CsgD-independent paradigm for the formation of cholesterol-attached Typhi biofilms, and emphasized the role(s) of stress signaling pathways for adaptation in chronic infections. Our identification of the biofilm regulators in S. Typhi paves the way for the development of drugs against typhoid carriage, which will ultimately control the increased incidence of gall bladder cancer in typhoid carriers.

Dissecting the Reduced Penetrance of Putative Loss-of-Function Variants in Population-Scale Biobanks.

Loss-of-function variants (LoFs) disrupt the activity of their impacted gene. They are often associated with clinical phenotypes, including autosomal dominant diseases driven by haploinsufficiency. Recent analyses using biobanks have suggested that LoF penetrance for some haploinsufficient disorders may be low, an observation that has important implications for population genomic screening. However, biobanks are also rife with missing data, and the reliability of these findings remains uncertain. Here, we examine the penetrance of putative LoFs (pLoFs) using a cohort of ≈24,000 carriers derived from two population-scale biobanks: the UK Biobank and the All of Us Research Program. We investigate several possible etiologies for reduced pLoF penetrance, including biobank recruitment biases, annotation artifacts, missed diagnoses, and incomplete clinical records. Systematically accounting for these factors increased penetrance, but widespread reduced penetrance remained. Therefore, we hypothesized that other factors must be driving this phenomenon. To test this, we trained machine learning models to identify pLoFs with high penetrance using the genomic features specific to each variant. These models were predictive of penetrance across a range of diseases and ploF types, including those with prior evidence for pathogenicity. This suggests that reduced ploF penetrance is in fact common, and care should be taken when counseling asymptomatic carriers.

8332 Genotype/Phenotype Profile Of Pheochromocytoma/Paraganglioma Patients In A Single Tertiary Referral Center Of South Texas

Abstract Disclosure: V. Desai: None. M.A. Escobar Vasco: None. C. Estrada-Zuniga: None. B. Landry: None. H. Gonzalez-Cantu: None. D. Pruthi: None. F. Tozzi: None. J. Ferrell: None. M. Kitano: None. C. Solis-Herrera: None. J.M. Bruder: None. S. Raghunathan: None. P.L. Dahia: None. Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors. Nearly 40% of patients with PPGLs have a heritable germline mutation and around 30% carry somatic mutations in one of &amp;gt;20 known susceptibility genes. 15-20% of cases can progress to metastatic disease. Recently, ethnic differences have been suggested in PPGLs and support further evaluation of ethnically diverse cohorts which can offer guidance for surveillance and patient care. Goal: The objective of this study is to identify genetic and clinical features of patients with a diagnosis of PPGL in predominant ethnic groups located in a single tertiary referral center of South Texas that is a designated Pheo-Para Alliance Clinical and Research Center of Excellence. Methods: Medical records were utilized to obtain demographic and clinical data, including age at diagnosis, gender, ethnicity, family history, tumor location, metastasis, clinical disease vs. carrier status, and genotype from patients enrolled in an IRB-approved repository. Results: 62 index patients who were diagnosed with PPGL or had a pathogenic germline mutation with no clinical disease were enrolled between 2006 to 2023. Patients were predominantly Caucasian (n=30/59, 50.8%) and Hispanic (n=24/59, 40.6%). In the Hispanic group, twenty-one were diagnosed with PPGL and three were asymptomatic carriers. This group had an average age of 38.3 years (range, 13-77), 85.7% had pheochromocytomas (11.1% were bilateral), 14.3% were metastatic, 16.7% had a positive family history, and 65% had an identifiable germline mutation. The most commonly mutated genes in Hispanics were VHL (n=5), SDHx (n=5), and EPAS1 (n=3). In the Caucasian group, thirty patients were diagnosed with PPGL and three were asymptomatic carriers. The average age for Caucasians was 46.4 years (range, 19-80). 23% had a positive family history, 66.7% had pheochromocytoma, 22.2% had metastatic disease, and 77.3% had a germline mutation. The most common genotype in Caucasians was SDHx (n=12) followed by NF1 (n=4). Conclusion: In this PPGL cohort, Hispanic patients tended to be younger at diagnosis, have lower proportion of SDH germline mutations and higher frequency of somatic mutations compared to Caucasians. This preliminary observation should inform further investigation into PPGL genotype-phenotype associations across ethnic groups toward improving surveillance and patient care. Presentation: 6/2/2024

7990 Reduced Alpha-1 Antitrypsin Activity Is Associated with Higher Plasma Free Cortisol and Increased Tissue Glucocorticoid Exposure in Humans in vivo

Abstract Disclosure: L.D. Boyle: None. M. Nixon: None. C.M. Underhill: None. L.A. Hill: None. N.Z. Homer: None. M. Magennis: None. R. Andrew: None. G.L. Hammond: None. J.G. Lewis: None. R.H. Stimson: None. B.R. Walker: None. Background: Corticosteroid Binding Globulin (CBG) binds &amp;gt;85% of plasma cortisol, modulating its biological activity. Proteolytic cleavage by neutrophil elastase (NE) reduces CBG binding capacity, proposed to increase free cortisol availability to inflamed tissues. Genetic variation at the locus spanning SERPINA1 (encoding alpha-1 antitrypsin, AAT, the endogenous inhibitor of NE) and SERPINA6 (CBG) altered morning total plasma cortisol. We hypothesised that AAT deficiency increased CBG cleavage and hence free plasma cortisol, resulting in amplified tissue cortisol delivery and increased HPA axis negative feedback. We tested this in recall-by-genotype studies of people who are heterozygous for inactivating mutations in SERPINA1. Methods: 16 asymptomatic carriers of deleterious SERPINA1 single nucleotide polymorphisms (rs17580 &amp; rs28929474) and 16 age-, gender- and BMI-matched controls were recruited from the Generation Scotland Biobank. To quantify in vivo whole body glucocorticoid appearance and clearance rates, and estimate tissue cortisol uptake, we performed arterio-venous plasma sampling across abdominal adipose and skeletal muscle during steady-state 9,11,12,12-[2H]4-cortisol tracer infusion. To assess endogenous negative feedback, participants underwent combined receptor antagonist stimulation of the HPA axis (‘CRASH’) testing using RU486 and spironolactone, or placebo in a double blind randomised crossover design. Total cortisol (LC-MS/MS), free cortisol (isotopic dilution &amp; ultrafiltration), CBG binding capacity (radioligand displacement), CBG concentration and AAT (ELISA) were measured in plasma. Tissue cortisol (LC-MS/MS) and glucocorticoid-dependent transcripts (qPCR) were measured in adipose biopsy samples collected at end of study. Results: AAT was ∼30% lower in AAT+/- (p=0.0002 vs control). Plasma CBG concentration, binding capacity and total cortisol were similar between groups. However, plasma free cortisol fraction was higher in AAT+/- subjects (16.1 +/- 0.2 vs 13.9 +/- 0.04 %, p&amp;lt;0.0001). Adipose tissue from AAT+/- subjects displayed increased cortisol levels and increased glucocorticoid-responsive transcripts PER1 and LPL compared to controls. Consistent with release from CBG, total and free cortisol release across skeletal muscle was increased in AAT+/- subjects vs controls. The rate of appearance of 9,12,12-[2H]3-cortisol was reduced in AAT+/- (p=0.03 vs control), consistent with decreased whole body 11β-HSD1 activity. CRASH testing did not reveal additional differences between groups. Discussion: Subclinical AAT deficiency is associated with a higher free cortisol fraction and increased tissue glucocorticoid exposure. Although consistent with the hypothesis of local tissue-mediated control of glucocorticoid exposure via the NE/AAT/CBG axis, these findings were not accompanied by measurable changes in CBG. Presentation: 6/3/2024

9225 Reduced Alpha-1 Antitrypsin Activity Is Associated with Higher Plasma Free Cortisol and Increased Tissue Glucocorticoid Exposure in Humans in vivo

Abstract Disclosure: L.D. Boyle: None. M. Nixon: None. C.M. Underhill: None. L.A. Hill: None. N.Z. Homer: None. M. Magennis: None. R. Andrew: None. G.L. Hammond: None. J.G. Lewis: None. R.H. Stimson: None. B.R. Walker: None. Background Corticosteroid Binding Globulin (CBG) binds &amp;gt;85% of plasma cortisol, modulating its biological activity. Proteolytic cleavage by neutrophil elastase (NE) reduces CBG binding capacity, proposed to increase free cortisol availability to inflamed tissues. Genetic variation at the locus spanning SERPINA1 (encoding alpha-1 antitrypsin, AAT, the endogenous inhibitor of NE) and SERPINA6 (CBG) altered morning total plasma cortisol. We hypothesised that AAT deficiency increased CBG cleavage and hence free plasma cortisol, resulting in amplified tissue cortisol delivery and increased HPA axis negative feedback. We tested this in recall-by-genotype studies of people who are heterozygous for inactivating mutations in SERPINA1. Methods 16 asymptomatic carriers of deleterious SERPINA1 single nucleotide polymorphisms (rs17580 &amp; rs28929474) and 16 age-, gender- and BMI-matched controls were recruited from the Generation Scotland Biobank. To quantify in vivo whole body glucocorticoid appearance and clearance rates, and estimate tissue cortisol uptake, we performed arterio-venous plasma sampling across abdominal adipose and skeletal muscle during steady-state 9,11,12,12-[2H]4-cortisol tracer infusion. To assess endogenous negative feedback, participants underwent combined receptor antagonist stimulation of the HPA axis (‘CRASH’) testing using RU486 and spironolactone, or placebo in a double blind randomised crossover design. Total cortisol (LC-MS/MS), free cortisol (isotopic dilution &amp; ultrafiltration), CBG binding capacity (radioligand displacement), CBG concentration and AAT (ELISA) were measured in plasma. Tissue cortisol (LC-MS/MS) and glucocorticoid-dependent transcripts (qPCR) were measured in adipose biopsy samples collected at end of study. Results AAT was ∼30% lower in AAT+/- (p=0.0002 vs control). Plasma CBG concentration, binding capacity and total cortisol were similar between groups. However, plasma free cortisol fraction was higher in AAT+/- subjects (16.1 +/- 0.2 vs 13.9 +/- 0.04 %, p&amp;lt;0.0001). Adipose tissue from AAT+/- subjects displayed increased cortisol levels and increased glucocorticoid-responsive transcripts PER1 and LPL compared to controls. Consistent with release from CBG, total and free cortisol release across skeletal muscle was increased in AAT+/- subjects vs controls. The rate of appearance of 9,12,12-[2H]3-cortisol was reduced in AAT+/- (p=0.03 vs control), consistent with decreased whole body 11β-HSD1 activity. CRASH testing did not reveal additional differences between groups. Discussion Subclinical AAT deficiency is associated with a higher free cortisol fraction and increased tissue glucocorticoid exposure. Although consistent with the hypothesis of local tissue-mediated control of glucocorticoid exposure via the NE/AAT/CBG axis, these findings were not accompanied by measurable changes in CBG. Presentation: 6/3/2024