Unknown Significance Research Articles

Prenatal risk assessment of Xp21.1 duplication involving the DMD gene by optical genome mapping.

Structural variants (SVs) of unknown significance are great challenges for prenatal risk assessment, especially when involving dose-sensitive genes such as DMD The pathogenicities of 5'-terminal DMD duplications in the database remain controversial. Four prenatal cases with Xp21.1 duplications were identified by routine prenatal genomic testing, encompassing the 5'-UTR to exons 1-2 in family 1 and family 2, and to exons 1-9 in family 3. The duplication in family 4 was non-contiguous covering the 5'-UTR to exon 1 and exons 3-7. All were traced to unaffected males in the family pedigrees. A new genome-wide approach of optical genome mapping was performed in families 1, 2, and 3 to delineate the breakpoints and orientation of the duplicated fragments. The extra copies were tandemly inserted into the upstream of DMD, preserving the integrity of ORF from the second copy. The pathogenicities were thus reclassified as likely benign. Our data highlight the importance of structural delineation by optical genome mapping in prenatal risk assessment of incidentally identified SVs involving DMD and other similar large dose-sensitive genes.

Cardiovascular Disease Pathogenicity Predictor (CVD-PP): A Tissue-Specific In Silico Tool for Discriminating Pathogenicity of Variants of Unknown Significance in Cardiovascular Disease Genes.

Interpretation of variants of uncertain significance (VUSs) remains a challenge in the care of patients with inherited cardiovascular diseases (CVDs); 56% of variants within CVD risk genes are VUS, and machine learning algorithms trained upon large data resources can stratify VUS into higher versus lower probability of contributing to a CVD phenotype. We used ClinVar pathogenic/likely pathogenic and benign/likely benign variants from 47 CVD genes to build a predictive model of variant pathogenicity utilizing measures of evolutionary constraint, deleteriousness, splicogenicity, local pathogenicity, cardiac-specific expression, and population allele frequency. Performance was validated using variants for which the ClinVar pathogenicity assignment changed. Functional validation was assessed using prior studies in >900 identified VUS. The model utility was demonstrated using the Catheterization Genetics cohort. We identified a top-ranked model that accurately prioritized variants for which ClinVar clinical significance had changed (n=663; precision-recall area under the curve, 0.97) and performed well compared with conventional in silico methods. This model (CVD pathogenicity predictor) also had high accuracy in prioritizing VUS with functional effects in vivo (precision-recall area under the curve, 0.58). In Catheterization Genetics, there was a greater burden of higher CVD pathogenicity predictor scored VUS in individuals with dilated cardiomyopathy compared with controls (P=8.2×10-15). Of individuals in Catheterization Genetics who harbored highly ranked CVD pathogenicity predictor VUS meeting clinical pathogenicity criteria, 27.6% had clinical evidence of disease. Variant prioritization using this model increased genetic diagnosis in Catheterization Genetics participants with a known clinical diagnosis of hypertrophic cardiomyopathy (7.8%-27.2%). We present a cardiac-specific model for prioritizing variants underlying CVD syndromes with high performance in discriminating the pathogenicity of VUS in CVD genes. Variant review and phenotyping of individuals carrying VUS of pathogenic interest support the clinical utility of this model. This model could also have utility in filtering variants as part of large-scale genomic sequencing studies.

Localized blastic plasmacytoid dendritic cell neoplasm associated with progressive clonal hematopoiesis and myelodysplastic syndrome.

Clonal hematopoiesis is highly prevalent in elderly patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), and around 20% of BPDCN patients have an associated myeloid malignancy. We present a patient with localized BPDCN and concomitant myelodysplastic syndrome (MDS), previously followed for several years due to clonal cytopenia of unknown significance. Compared targeted next-generation sequencing (NGS) of the skin tumor and sequential bone marrow samples showed shared variants in ASXL1 and TET2 with a de novo NRAS variant in both BPDCN and MDS compared to preceding bone marrow samples. These findings illustrate a shared clonal origin of BPDCN and MDS resulting from progressive clonal hematopoiesis.

Genotype predicts heart failure independent of left ventricular ejection fraction and NT-proBNP levels in hypertrophic cardiomyopathy

Abstract Background/Introduction Hypertrophic cardiomyopathy (HCM) is a myocardial disease associated with progression to heart failure. In around 40% of cases, the disease is caused by variants in genes encoding sarcomere proteins. Purpose To evaluate the role of genotype in predicting heart failure (HF) outcomes. Methods In this observational single-centre cohort study, consecutive patients with HCM were assessed for heart failure clinically stratified by genetic status into genotype-elusive which included those with no significant variants (G-) or variants of unknown significance (VUS) and genotype-positive (G+) with pathogenic/likely pathogenic (LP/P) variants. Heart failure endpoint was defined as left ventricular assist device implantation, heart transplantation or heart-failure-related death. The incidence of HF endpoint was compared between genotypes during follow-up using a time-to-event analysis. Results 474 patients (50.9 ±14.5 years, 67.3 males) with HCM (25% with left ventricular (LV) outflow obstruction) were followed for 10.9 years (IQR 5.1-13.5). G+ LP/P patients (201/474 (42.4%)) were younger (45.8. ±14.0 years) compared to G- (225/474 (47.5%), 55.2 ±13.4 years) and VUS (48/474 (10.1%), 52.0 ± 15 years); 29/474 (6.1%) reached the heart failure endpoint. The incidence of heart failure endpoints was 12.4% (25/201) in the G+ LP/P group compared to 1.5% (4/273) in the gene elusive group. A multivariate Cox proportional hazards model including NT-proBNP and LV ejection fraction (LVEF) and genetic status showed that G+ LP/P was associated with increased risk of heart failure outcomes (HR: 5.11, 95% CI: 1.43–18.25, p=0.012). Every 100-unit rise in NT-proBNP was associated with a 41% increase in risk (HR: 1.41, 95% CI: 1.20–1.66, p<0.0001). A one-unit (1%) reduction in LVEF correlated with a 10% increase in heart failure risk (HR: -0.90, 95% CI: 0.87–0.93, p<0.0001). Conclusion(s) Genetic status is a predictor of heart failure outcomes independent of LVEF and NT-proBNP levels in HCM. This underscores the importance of genetic testing in the clinical management of HCM.

Whole exome sequencing in patients with recurrent pericarditis

Abstract Background/Introduction About 10% of patients with recurrences may have a family history of pericarditis suggesting a genetic predisposition, that has been confirmed in selected cases with idiopathic recurrent pericarditis with a focused analysis of genes involved in autoinflammatory diseases (TNFRSF1A, MVK, NLRP3 genes, and variants at the Interleukin 1 Gene Locus). Purpose Aim of the present paper is to describe the frequency of detected variants of causative genes by Whole Exome Sequencing (WES) in patients with idiopathic recurrent pericarditis. Methods This is an observational, cohort study including all consecutive adult patients (>18 years) with > 2 episodes of recurrent pericarditis. All patients performed WES. We analyzed the frequency of genetic variants in: 1) known or predicted to be at least likely pathogenic (LP) variants already related to recurrent pericarditis, 2) predicted at least of unknown significance in genes not yet associated with recurrent pericarditis. Moreover, we highlighted incidental findings. Results We studied 108 patients with recurrent pericarditis (median age of 32 years, IQR 18.5; 67.6% females, all Caucasian, idiopathic etiology in 71.1%). The median number of recurrences was 5 (IQR 2). Eleven gene variants related to recurrent pericarditis were detected by WES analysis in 11/108 patients (10.2%): 9 variants were pathogenic/likely pathogenic (P/LP) according the ACMG guidelines and involved NLRP3 and TNFRSF1A genes, 2 VUS associated with familial Mediterranean fever (gene MEFV) (figure 1). We also recorded 3 P/LP variants and 2 VUS related to the inflammatory response (IFIH1, NFKBIA, JAK1, NOD2 and ALPK1 genes); 7 P/LP variants and 3 VUS related to heart’s electrical system (SCN5A, CALM2, TRPM4, KCND2, KCNQ1 genes); 12 P/LP variants and 10 VUS related to heart structural genes (figure 2). Conclusion(s) A substantial proportion of patients with multiple recurrences of pericarditis carries LP or P variants suggesting the importance of genetic predisposition evaluation in this population.

Metabolomic profiling of the entire UK Biobank enables interpretation of familial hypercholesterolemia mutations and prediction of severe cardiovascular outcomes

Abstract Background Familial hypercholesterolemia (FH) is an inherited disorder resulting in high levels of LDL-C from birth. Premeature coronary heart disease occurs in half of affected men by age 50 years(1). While many genetic variants that cause FH are well understood, there are also many variants in FH genes that are of uncertain clinical significance. Furthermore, the variability in residual cardiovascular risk of FH carriers after statin treatment is not fully understood. We here investigate whether metabolomic and genomic data from the 500,000 person UK Biobank cohort can aid in interpretation of candidate pathogenic variants for FH, and characterise future risk of severe cardiac events in the carriers of such variants. Methods We have quantified 249 metabolomic parameters in 490,830 blood samples from UK Biobank cohort. Among 186,483 participants with exome sequence data we identified 896 who carried known pathogenic FH variants and 405 who carried variants of unknown significance in an established FH gene. We fitted a logistic predictive model to identify pathogenic mutations using LDL levels, statin use and 17 principal components of the metabolomic parameters. We further tested whether metabolomic and genomic scores for predicting future risk of myocardial infarction (MI), that were trained in the general population (i.e. individuals without FH), could predict risk in FH carriers. Results A model including all metabolites had a higher accuracy at identifying known pathogenic FH variants (36/56 at FDR < 0.05), compared to LDL and statin use alone (30/56). Our model also identified 8 FH variants marked as uncertain significance in ClinVar with significant (FDR < 0.05) evidence of predicted pathogenicity. We found that our metabolomic risk score predicted 10-year risk of MI among FH carriers (HR=1.96 per SD, p = 0.0011). This was indeed stronger than the effect in the general population (HR = 1.64 per SD, p = 2.5e-168). A combined metabolomic and polygenic risk score had an even larger effect at predicting MI in FH carriers (HR = 3.06 per SD, p = 2.0e-6), and this score was significantly better at predicting MI in FH carriers than in non-carriers (HR = 3.06 vs 1.88 per SD, interaction p = 0.042). Conclusion Familial hypercholesterolemia is an important source of risk for early cardiovascular disease. Population-scale metabolomics can help distinguish pathogenic from benign variants that have not yet been characterised. Metabolomic and genomic scores can also identify individuals at most elevated risk, and provide even more information to FH individuals than in the general population.

Postnatal outcomes of fetal variants of unknown significance in prenatal CMA: A single-center study.

Chromosome microarray analysis(CMA) can identify clinically significant microdeletions and microduplications, providing valuable insights into the genetic basis of various disorders. Our study was to evaluate clinical management and prognosis of fetuses with prenatal variants of unknown significance (VOUS) and determine diagnostic approaches for subsequent pregnancies. This study included 2,953 fetuses undergoing chromosome microarray analysis (CMA) at the Prenatal Diagnostic Center of Changzhou Maternal and Child Health Care Hospital from January 2018 to December 2022, identifying 162 cases with VOUS. Parent-of-origin testing determined the origin of copy number variations (CNVs). Prenatal genetic counseling was provided, and outcomes were followed for 3-36 months post-birth. All 162 VOUS cases received prenatal genetic counseling. Among these, 123 continued the pregnancy; 22 chose termination, and 17 were lost to follow-up. Of the continuations, 116 delivered at term, and 7 preterm. Post-birth follow-up showed 5/123 live-born fetuses developed relevant clinical phenotypes. Parent-of-origin testing in 21 cases identified 18 hereditary and 3 de novo variants. Additionally, five subsequent pregnancies were monitored, with two undergoing amniocentesis and three receiving low-risk non-invasive prenatal testing (NIPT), all with positive outcomes. VOUS, occurring in approximately 5% of cases, require comprehensive prenatal genetic counseling and show generally favorable outcomes. Despite low association with adverse clinical phenotypes, the importance of postnatal follow-up and regular report updates is emphasized to detect potential clinical associations early.

Identification and Copy Number Variant Analysis of Enhancer Regions of Genes Causing Spinocerebellar Ataxia.

Currently, routine diagnostics for spinocerebellar ataxia (SCA) look for polyQ repeat expansions and conventional variations affecting the proteins encoded by known SCA genes. However, ~40% of the patients still remain without a genetic diagnosis after routine tests. Increasing evidence suggests that variations in the enhancer regions of genes involved in neurodegenerative disorders can also cause disease. Since the enhancers of SCA genes are not yet known, it remains to be determined whether variations in these regions are a cause of SCA. In this pilot project, we aimed to identify the enhancers of the SCA genes ATXN1, ATXN3, TBP and ITPR1 in the human cerebellum using 4C-seq, publicly available datasets, reciprocal 4C-seq, and luciferase assays. We then screened these enhancers for copy number variants (CNVs) in a cohort of genetically undiagnosed SCA patients. We identified two active enhancers for each of the four SCA genes. CNV analysis did not reveal any CNVs in the enhancers of the four SCA genes in the genetically undiagnosed SCA patients. However, in one patient, we noted a CNV deletion with an unknown clinical significance near one of the ITPR1 enhancers. These results not only reveal elements involved in SCA gene regulation but can also lead to the discovery of novel SCA-causing genetic variants. As enhancer variations are being increasingly recognized as a cause of brain disorders, screening the enhancers of ATXN1, ATXN3, TBP and ITPR1 for variations other than CNVs and identifying and screening enhancers of other SCA genes might elucidate the genetic cause in undiagnosed patients.

Behavioral screening reveals a conserved residue in Y-Box RNA-binding protein required for associative learning and memory in C. elegans.

RNA-binding proteins (RBPs) regulate translation and plasticity which are required for memory. RBP dysfunction has been linked to a range of neurological disorders where cognitive impairments are a key symptom. However, of the 2,000 RBPs in the human genome, many are uncharacterized with regards to neurological phenotypes. To address this, we used the model organism C. elegans to assess the role of 20 conserved RBPs in memory. We identified eight previously uncharacterized memory regulators, three of which are in the C. elegans Y-Box (CEY) RBP family. Of these, we determined that cey-1 is the closest ortholog to the mammalian Y-Box (YBX) RBPs. We found that CEY-1 is both necessary in the nervous system for memory ability and sufficient to promote memory. Leveraging human datasets, we found both copy number variation losses and single nucleotide variants in YBX1 and YBX3 in individuals with neurological symptoms. We identified one predicted deleterious YBX3 variant of unknown significance, p.Asn127Tyr, in two individuals with neurological symptoms. Introducing this variant into endogenous cey-1 locus caused memory deficits in the worm. We further generated two humanized worm lines expressing human YBX3 or YBX1 at the cey-1 locus to test evolutionary conservation of YBXs in memory and the potential functional significance of the p.Asn127Tyr variant. Both YBX1/3 can functionally replace cey-1, and introduction of p.Asn127Tyr into the humanized YBX3 locus caused memory deficits. Our study highlights the worm as a model to reveal memory regulators and identifies YBX dysfunction as a potential new source of rare neurological disease.

Innovation in cancer pharmacotherapy through integrative consideration of germline and tumor genomes.

Precision cancer medicine is widely established, and numerous molecularly targeted drugs for various tumor entities are approved or in development. Personalized pharmacotherapy in oncology has so far been based primarily on tumor characteristics, e.g., somatic mutations. However, the response to drug treatment also depends on pharmacological processes summarized under the term ADME (absorption, distribution, metabolism, and excretion). Variations in ADME genes have been the subject of intensive research for more than five decades, considering individual patients' genetic makeup, referred to as pharmacogenomics (PGx). The combined impact of a patient's tumor and germline genome is only partially understood and often not adequately considered in cancer therapy. This may be attributed, in part, to the lack of methods for combined analysis of both data layers. Optimized personalized cancer therapies should, therefore, aim to integrate molecular information about the tumor and the germline, taking into account existing PGx guidelines for drug therapy. Moreover, such strategies should provide the opportunity to consider genetic variants of previously unknown functional significance. Bioinformatic analysis methods and corresponding algorithms for data interpretation need to be developed to consider PGx data in interdisciplinary molecular tumor boards, where cancer patients are discussed to provide evidence-based recommendations for clinical management based on individual tumor profiles. Significance Statement The era of personalized oncology has seen the emergence of drugs tailored to genetic variants associated with cancer biology. However, full potential of targeted therapy remains untapped due to the predominant focus on acquired tumor-specific alterations. Optimized cancer care must integrate tumor and patient genomes, guided by pharmacogenomic principles. An essential prerequisite for realizing truly personalized drug treatment of cancer patients is the development of bioinformatic tools for comprehensive analysis of all data layers generated in modern precision oncology programs.

Utility of Targeted Next Generation Sequencing (NGS) to Predict Hematologic Neoplasms with Germline Predisposition

Abstract Introduction/Objective Hematologic neoplasms with germline predisposition are increasingly gaining clinical relevance as associated gene variants are emerging. These variants confer an increased risk for developing hematologic neoplasms as additional somatic aberrations accumulate. Recognition of germline predisposition is crucial to patient management as it would prompt genetic counseling and regular surveillance in affected patients and biological family members, as well as guide therapy, as many patients undergo allogeneic stem cell transplantation for which relatives are typically the preferred donors. Furthermore, these patients may respond differently to conventional therapies. Clinical recognition of germline predisposition is challenging due to phenotypic heterogeneity and a lack of germline testing standards and resources. Next generation sequencing is routinely utilized to detect somatic variants associated with hematopoietic neoplasms. Molecular profiling may also potentially serve as a screening tool to suggest pathogenic germline variants. Methods/Case Report Comprehensive genomic profiling data was reviewed for 301 patients with known hematologic neoplasms. A somatic-germline-zygosity (SGZ) computational method classified variants by origin. Variants of unknown clinical significance were excluded. The final study showed 94 patients predicted to have germline variants. The variables analyzed include germline variants, concurrent mutations, diagnosis, sex, age, and ancestry. Results (if a Case Study enter NA) Acute myeloid leukemia was the most frequent diagnosis, followed by B-cell acute lymphoblastic leukemia, myeloproliferative neoplasms, myelodysplastic syndrome, and chronic myelomonocytic leukemia. The median patient age was 60 years, ranging from 6 months to 91 years. Male gender and European ancestry were proportionally greater. In this study, we identified 70 distinct genes with 145 germline pathogenic variants. The most common pathogenic germline variants were TET2, SRSF2, RUNX1, DNMT3A, and CHEK2. Conclusion In conclusion, SGZ computational methods can be used as a screening tool to predict possible germline mutations in hematologic malignancies, which will help guide treatment and improve patient and family outcomes

Next-generation technology in epilepsy diagnostic: First Moroccan pediatric case series and literature review.

Background: Pediatric epilepsy is the most prevalent neurological disorder among children, characterized by significant heterogeneity in terms of etiology, clinical presentation, and prognosis. In developed countries, genetic testing, particularly next-generation sequencing (NGS), has become standard practice for diagnosis. Methods/Observation: This paper presents the first pediatric Moroccan case series with epilepsy. The diagnosis was established using whole-exome sequencing which identified five variants. Moreover, we evaluated the effectiveness of different NGS technologies in epilepsy diagnosis by conducting a PubMed search with targeted keywords. Results: Whole-exome sequencing and whole-genome sequencing are more effective for epilepsy diagnosis than multi-gene panels. However, they also present significant challenges including false negatives and variants of unknown significance which complicate genetic interpretation and diagnostic process. Conclusion: Despite these limitations, the rapid accumulation of genetic data and advancements in bioinformatic tools are expected to address these issues, improving diagnostic accuracy. Keywords: Epilepsy, Next-generation sequencing, Neuropediatry, Genetics, Morocco.

Performance of a Protein Language Model for Variant Annotation in Cardiac Disease.

Genetic testing is a cornerstone in the assessment of many cardiac diseases. However, variants are frequently classified as variants of unknown significance, limiting the utility of testing. Recently, the DeepMind group (Google) developed AlphaMissense, a unique artificial intelligence-based model, based on language model principles, for the prediction of missense variant pathogenicity. We aimed to report on the performance of AlphaMissense, accessed by VarCardio, an open web-based variant annotation engine, in a real-world cardiovascular genetics center. All genetic variants from an inherited arrhythmia program were examined using AlphaMissense via VarCard.io and compared with the ClinVar variant classification system, as well as another variant classification platform (Franklin by Genoox). The mutation reclassification rate and genotype-phenotype concordance were examined for all variants in the study. We included 266 patients with heritable cardiac diseases, harboring 339 missense variants. Of those, 230 (67.8%) were classified by ClinVar as either variants of unknown significance or nonclassified. Using VarCard.io, 198 variants of unknown significance (86.1%, 95% CI, 80.9-90.3) were reclassified to either likely pathogenic or likely benign. The reclassification rate was significantly higher for VarCard.io than for Franklin (86.1% versus 34.8%, P<0.001). Genotype-phenotype concordance was highly aligned using VarCard.io predictions, at 95.9% (95% CI, 92.8-97.9) concordance rate. For 109 variants classified as pathogenic, likely pathogenic, benign, or likely benign by ClinVar, concordance with VarCard.io was high (90.5%). AlphaMissense, accessed via VarCard.io, may be a highly efficient tool for cardiac genetic variant interpretation. The engine's notable performance in assessing variants that are classified as variants of unknown significance in ClinVar demonstrates its potential to enhance cardiac genetic testing.

Clinical and genetic analysis of a Chinese pedigree affected with Familial focal epilepsy with variable foci due to variant of NPRL3 gene

To explore the clinical manifestations and genetic etiology of a Chinese pedigree affected with Familial focal epilepsy with variable foci (FFEVF). A FFEVF pedigree presented at the Department of Medical Genetics of Linyi Maternal and Child Health Care Hospital on March 14, 2023 was selected as the study subject. The proband was subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing of the proband and other affected members and bioinformatic analysis. This study was approved by the Linyi Maternal and Child Health Care Hospital (Ethics No. QTL-YXLL-2023048). WES revealed that the proband has harbored a heterozygous c.1642C>T (p.Arg548Cys) missense variant in exon 15 of the NPRL3 gene. Sanger sequencing confirmed that the variant was inherited from the proband's father, and multiple members of the pedigree had also harbored the same variant. Based on guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as variant of unknown significance (PM2_supporting + PP3). The clinical phenotype of FFEVF patients caused by variants of NPRL3 gene is extensive, and the patients may present with neurological abnormality of autism spectrum disorder in addition to seizures.

A Systematic Literature Review on the Global Status of Newborn Screening for Mucopolysaccharidosis II.

A systematic literature review was conducted to determine the global status of newborn screening (NBS) for mucopolysaccharidosis (MPS) II (Hunter syndrome; OMIM 309900). Electronic databases were searched in July 2023 for articles referencing NBS for lysosomal storage diseases: 53 featured MPS II. Until recently, only Taiwan and two US states (Illinois and Missouri) formally screened newborns for MPS II, although pilot programs have been conducted elsewhere (Japan, New York, and Washington). In 2022, MPS II was added to the US Recommended Uniform Screening Panel, with increased uptake of NBS anticipated across the USA. While the overall MPS II birth prevalence, determined from NBS initiatives, was higher than in previous reports, it was lower in the USA (approximately 1 in 73,000 according to recent studies in Illinois and Missouri) than in Asia (approximately 1 in 15,000 in Japan). NBS programs typically rely on tandem mass spectrometry quantification of iduronate-2-sulfatase activity for first-tier testing. Diagnosis is often confirmed via molecular genetic testing and/or biochemical testing but may be complicated by factors such as pseudodeficiency alleles and variants of unknown significance. Evidence relating to MPS II NBS is lacking outside Taiwan and the USA. Although broad benefits of NBS are recognized, few studies specifically explored the perspectives of families of children with MPS II.

Mapping multimodal phenotypes to perturbations in cells and tissue with CRISPRmap.

Unlike sequencing-based methods, which require cell lysis, optical pooled genetic screens enable investigation of spatial phenotypes, including cell morphology, protein subcellular localization, cell-cell interactions and tissue organization, in response to targeted CRISPR perturbations. Here we report a multimodal optical pooled CRISPR screening method, which we call CRISPRmap. CRISPRmap combines in situ CRISPR guide-identifying barcode readout with multiplexed immunofluorescence and RNA detection. Barcodes are detected and read out through combinatorial hybridization of DNA oligos, enhancing barcode detection efficiency. CRISPRmap enables in situ barcode readout in cell types and contexts that were elusive to conventional optical pooled screening, including cultured primary cells, embryonic stem cells, induced pluripotent stem cells, derived neurons and in vivo cells in a tissue context. We conducted a screen in a breast cancer cell line of the effects of DNA damage repair gene variants on cellular responses to commonly used cancer therapies, and we show that optical phenotyping pinpoints likely pathogenic patient-derived mutations that were previously classified as variants of unknown clinical significance.

Two novel families with RUNX1 variants indicate glycine 168 as a new mutational hotspot: Implications for FPD/AML diagnosis.

Correct interpretation of the pathogenicity of germline RUNX1 variants is essential for FPD/AML diagnosis, clinical management and leukaemia surveillance. We report two families with clear FPD/AML phenotypic features harbouring missense variants at RHD critical residue Gly168. Although classified as of unknown significance (VUS) by RUNX1-specific curation guidelines, these variants should rather be considered likely pathogenic, as supported by computational tools, structural modelling and dysregulated platelet expression of RUNX1-targets, adding Gly168 among amino acids currently recognised as mutational hotspots. Our data could help reduce the number of variants classified as VUS, providing evidence for updating RUNX1 guidelines, thus improving FPD/AML diagnosis.

9189 Medullary Thyroid Cancer Due To A Novel Ret Oncogene Mutation In A Patient On Glp-1 Receptor Agonist

Abstract Disclosure: K. Lamar: None. D. John: None. O. Faour: None. N. Meda: None. M. Kinaan: None. Introduction: Mutations in the RET oncogene have been associated with increased risk of endocrine neoplasia and Medullary Thyroid Cancer (MTC). We report the case of a patient who has a (c.3281G&amp;gt;A) RET mutation, previously reported as a variant of uncertain significance. Case: A 51-year-old lady presented to our endocrine clinic for routine management of hypothyroidism, type 2 diabetes mellitus, and obesity. She had been on liraglutide, metformin, glipizide, and basal insulin for several years with good diabetes management. She had also been on levothyroxine for more than 10 years. On physical examination, a right thyroid lobe nodule was palpated. We performed a neck ultrasound which revealed a solid, isoechoic nodule measuring (1.23 x 1.42 x 2.00 cm) with no calcifications. Fine needle aspiration was consistent with MTC. She denied family history of thyroid cancer. She was advised to stop liraglutide immediately given risk of MTC with GLP-1 receptor agonist use. Preoperative calcitonin and CEA were markedly high at 935 pg/mL and 60.3 ng/mL, respectively. Fortunately, Gallium Ga-68 dotatate PET CT showed no signs of metastatic disease. The patient underwent a total thyroidectomy with bilateral central and lateral neck dissection. No cervical metastases were noted on lymph node dissection. Genetic tumor testing demonstrated a mutation in the RET oncogene (c.3281G&amp;gt;A), which was previously reported as a variant with unknown significance. Screening for hyperparathyroidism and pheochromocytoma was normal. Postoperative calcitonin and CEA were &amp;lt;2.0 pg/mL and 3.2 ng/mL respectively. The patient continues MTC surveillance under the care of a multidisciplinary team. Discussion: Our case is the first case in literature that identifies the RET oncogene (c.3281G&amp;gt;A) mutation as a pathogenic variant associated with MTC. It also emphasizes the need for close monitoring for thyroid nodules in patients on GLP-1 receptor agonists and pre-existing thyroid disease, through a comprehensive physical examination and neck ultrasound if needed. Presentation: 6/2/2024

8721 A Case of Congenital Hyperinsulinism Manifesting as Transient Hypoglycemia During Illness Due to Mosaic Variant of Unknown Significance in ABCC8

Abstract Disclosure: E.E. Bell-Sambataro: None. L. Mamilly: None. Background: Congenital hyperinsulinism (CHI) is characterized by inappropriate secretion of insulin during periods of low blood glucose. CHI can lead to significant complications such as seizures, developmental delays and neurologic damage. CHI can be caused by multiple genetic variants. The most common genetic etiologies are loss of function mutations in the genes ABCC8 and KCNJ11 encoding the pancreatic Beta (β)-cell ATP-sensitive potassium channel causing over secretion of insulin from the β-cells. We report a challenging pediatric case with a clinical presentation of CHI in an infant with a de novo mosaic ABCC8 gene variant of unknown significance manifesting only during times of illness. Clinical Case: A male infant born at 36 weeks gestational age was transferred to a tertiary center NICU secondary to seizure activity and hypoglycemia after the 24 hours of life with glucose levels as low as 32 mg/dL. His birth weight was normal and there was not maternal history of diabetes mellitus. The hypoglycemia persisted throughout the first week of life and required a glucose infusion rate of 11 mg/kg/min, without success in obtaining a critical sample. He had multiple seizures and MRI brain showed signs of hypoglycemic encephalopathy. Subsequently, he was weaned off IV dextrose and completed a 6 hour safety fast prior to discharge. Rapid genome testing resulted in a de novo, mosaic variant of unknown significance in ABCC8 (C.3622G&amp;gt;A resulting in amino acid substitution p.Glu1208Lys). His family reported significant but transient hypoglycemia during times of illness. At the age of 11 months, he was hospitalized for significant hypoglycemia during an episode of acute gastroenteritis and was treated with dextrose-containing fluids for 36 hours. A subsequent diagnostic fasting study resulted in hypoglycemia within 5.5 hours with capillary glucose of 49 mg/dL. At the time of hypoglycemia, beta hydroxybutyrate was inappropriately low at 0.78 mm, insulin level was suppressed &amp;lt;2 mcIU/mL. Glucagon (30 mcg/Kg) was administered after the initial sample was drawn with a significant increase in glucose from 49 mg/dL to 103 mg/dL. Based on the positive glucagon response and low serum ketone, the clinical diagnosis of CHI was made and diazoxide was initiated while awaiting other results. After the second dose of diazoxide, all glucose levels remained above 80 mg/dL. He was sent home on a continuous glucose monitor and diazoxide. Conclusion: CHI can occur due to autosomal recessive or autosomal dominant ABCC8 loss-of-function mutations of which more than half are not responsive to diazoxide. In this case report, we describe the diagnosis of hyperinsulinemic hypoglycemia in an infant with an ABCC8 variant classified with unknown significance. We describe a good initial response to diazoxide in normalizing blood glucose levels in this infant. Presentation: 6/2/2024

8481 A 32 Year Old Male With Recurrent Acute Pancreatits and Severe Hypertriglyceridemia: Importance of Considering Genetic Variants

Abstract Disclosure: M.F. Salazar Zelaya: None. J.D. Sibaja Jiménez: None. Background : Hypertriglyceridemia is a common medical scenario in daily practice, causing a variety of symptoms including recurrent episodes of acute pancreatits, which can be severe. Multiple genetic variants can lead to different spectrums of the disease. CLINICAL CASE: A 32 year old male police officer presented to our Endocrinology Outpatient Clinic with a history of long standing hypertriglyceridemia and six previous episodes of acute pancreatits, two in the last twelve months. Familiy history was negative for lipid disorders. The patient had adecuate adherence to diet and exercise as well to prescribed medications, which included Fenofibrate 250 mgs/day and Rosuvastatin 40 mgs/day. The patient denied consumption of alcoholic beverages. Recent abdominal ultrasound was reported without abnormalities. His lipid panel reported elevated triglycerides at 5831 mg/dl (n&amp;lt;150 mg/dl), Total Cholesterol normal at 147 (n&amp;lt;200 mg/dl), low HDL levels at 12 mg/dl (range 12-92 mg/dl) and direct LDL Cholesterol at 120 mg/dl. His TSH value was normal at 1.02 uUI/mL (range 0.55-4.78 uUI/mL). Creatinine level was normal at 0.81 mg/dl (range 0.7-1.3 mg/dl). Liver function tests were normal with AST level at 25 IU/L (range 13-39 IU/L) ALT levels at 22 IU/L (range 7-52 IU/L) and alcaline phosphatase at 62 IU/L (range 34-104 IU/L).His fasting glucose level were normal at 82 mg/dl (n&amp;lt;100 mg/dl). Due to a high Familial Chylomicronemia Syndrome clinical score (13 points) we proceeded with genetic analysis of this patient. Next Generation Sequencing for genes related with chylomicronemia (APOA5, APOC2, GPIHBP1,LMFI, LPL) was performed to determine gene sequence plus copy number variation.Two heterocigote variants were reported, both in the LPL gene. The first one: LPL (NM 000237.3) c.644&amp;gt;A;p.Gly215Glu heterozygous is a missense variant already reported in the literature, registered in ClinVar (ID 1522) and the Leiden Open Variation Database. This variant is classified as pathogenic according to criteria PS3, PM1, PP3, PP5 of the American College of Medical Genetics and Genomics. The second one: LPL (nm 000237.3): c.383C&amp;gt;A;p.Thr128Asn;heterozygous is also a missense variant which to the extent of our knowledge has previously been reported only once in the literature: ClinVar (ID 1520537). This variant is classified currently as of unknown clinical significance according to PM2 criteria. There is however and entry reported (PMID: 8778602) of another variant affecting the same codon (p.Thr128AIa) that is associated to chylomicronemia syndrome. Conclusion: In cases of severe hypertriglyceridemia, suspicion and determination of gene variants are of great importance nowadays as they could eventually guide treatment, given the availability in some countries (and currently pending FDA approval) of new pharmacological therapies such as apo C-III inhibitors. Presentation: 6/2/2024