Search

Diagnostic laboratories gather phenotypic data through requisition forms, but there is no consensus as to which data are essential for variant interpretation. The ClinGen Cardiomyopathy Variant Curation Expert Panel defined a phenotypic data set for hypertrophic cardiomyopathy (HCM) variant interpretation, with the goal of standardizing requisition forms. Phenotypic data elements listed on requisition forms from nine leading cardiomyopathy testing laboratories were compiled to assess divergence in data collection. A pilot of 50 HCM cases was implemented to determine the feasibility of harmonizing data collection. Laboratory directors were surveyed to gauge potential for adoption of a minimal data set. Wide divergence was observed in the phenotypic data fields in requisition forms. The 50-case pilot showed that although demographics and assertion of a clinical diagnosis of HCM had 86% to 98% completion, specific phenotypic features, such as degree of left ventricular hypertrophy, ejection fraction, and suspected syndromic disease, were completed only 24% to 44% of the time. Nine data elements were deemed essential for variant classification by the expert panel. Participating laboratories unanimously expressed a willingness to adopt these data elements in their requisition forms. This study demonstrates the value of comparing and sharing best practices through an expert group, such as the ClinGen Program, to enhance variant interpretation, providing a foundation for leveraging cumulative case-level data in public databases and ultimately improving patient care.

The online version of this article (https://doi.org/10.1016/j. gim.2021.09.012) contains supplementary material, which is available to authorized users. Purpose: In 2015, the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) published consensus standardized guidelines for sequence-level variant classification in Mendelian disorders. To increase accuracy and consistency, the Clinical Genome Resource Familial Hypercholesterolemia (FH) Variant Curation Expert Panel was tasked with optimizing the existing ACMG/AMP framework for disease-specific classification in FH. In this study, we provide consensus recommendations for the most common FH-associated gene, LDLR, where >2300 unique FH-associated variants have been identified. Methods: The multidisciplinary FH Variant Curation Expert Panel met in person and through frequent emails and conference calls to develop LDLR-specific modifications of ACMG/AMP guidelines. Through iteration, pilot testing, debate, and commentary, consensus among experts was reached. Results: The consensus LDLR variant modifications to existing ACMG/AMP guidelines include (1) alteration of population frequency thresholds, (2) delineation of loss-of-function variant types, (3) functional study criteria specifications, (4) cosegregation criteria specifications, and (5) specific use and thresholds for in silico prediction tools, among others. Conclusion: Establishment of these guidelines as the new standard in the clinical laboratory setting will result in a more evidence-based, harmonized method for LDLR variant classification worldwide, thereby improving the care of patients with FH. Clinical Genome Resource (ClinGen) is primarily funded by the National Human Genome Research Institute through the following 3 grants: U41HG006834, U41HG009649, and U41HG009650. ClinGen also receives support for content curation from the Eunice Kennedy Shriver National Institute of Child Health and Human Development through the following 3 grants: U24HD093483, U24HD093486, and U24HD093487. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. J.R.C. acknowledges her PhD fellowship funded by the Science and Technology Foundation (SFRH/BD/108503/2015). L.T. and T.F. are supported by the Ministry of Health of the Czech Republic (grant NU20-02-00261). S.E.H. is an Emeritus British Heart Foundation Professor and is funded by PG08/ 008 and by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. M.T. is supported by a Vanier Canada Graduate Scholarship. L.R.B. is a Michael Smith Foundation for Health Research scholar and a Canada Research Chair in Precision Cardiovascular Disease Prevention. R.A.H. is supported by the Jacob J. Wolfe Distinguished Medical Research Chair, the Edith Schulich Vinet Canada Research Chair in Human Genetics, the Martha G. Blackburn Chair in Cardiovascular Research, and operating grants from the Canadian Institutes of Health Research (Foundation Grant) and the Heart and Stroke Foundation of Ontario (G-18- 0022147). J.W.K. is supported by the National Institutes of Health through grants P30DK116074 (to the Stanford Diabetes Research Center), R01 DK116750, R01 DK120565, and R01 DK106236 and by the American Diabetes Association (grant #1-19-JDF-108). info:eu-repo/semantics/publishedVersion

Hereditary transthyretin amyloidosis (ATTRv [variant]) is a clinically heterogeneous, progressively debilitating, fatal disease resulting from the deposition of insoluble amyloid fibrils in various organs and tissues. Early diagnosis of ATTRv can be facilitated with genetic testing; however, such testing of the TTR gene identifies variants of uncertain significance (VUS) in a minority of cases, a small percentage of which have the potential to be pathogenic. The Akcea/Ambry VUS Initiative is dedicated to gathering molecular, clinical, and inheritance data for each TTR VUS identified by genetic testing programs to reclassify TTR variants to a clinically actionable status (e.g., variant likely pathogenic [VLP]) where appropriate.Classification criteria used here, based on recommendations from the American College of Medical Genetics and Genomics, are stringent and comprehensive, requiring distinct lines of evidence supporting pathogenesis.Three TTR variants have been reclassified from VUS to VLP, including c.194CT (p.A65V), c.172GC (p.D58H), and c.239CT (p.T80I). In each case, the totality of genetic, structural, and clinical evidence provided strong support for pathogenicity.Based on several lines of evidence, three TTR VUS were reclassified as VLP, resulting in a high likelihood of disease diagnosis for those and subsequent patients as well as at-risk family members.

PurposeIn 2015, the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) published consensus standardized guidelines for variant classification in Mendelian disorders. To increase accuracy and consistency, the Clinical Genome Resource (ClinGen) Familial Hypercholesterolemia (FH) Variant Curation Expert Panel (VCEP) was tasked with optimizing the existing ACMG/AMP framework for disease-specific classification in FH. Here, we provide consensus recommendations for the most common FH-causing gene, LDLR, where >2,300 unique FH-associated variants have been identified.MethodsThe multidisciplinary FH VCEP met in person and through frequent emails and conference calls to develop LDLR-specific modifications of ACMG/AMP guidelines. Through iteration, pilot testing, debate and commentary, consensus among experts was reached.ResultsThe consensus LDLR variant modifications to existing ACMG/AMP guidelines include: 1) alteration of population frequency thresholds; 2) delineation of loss-of-function variant types; 3) functional study criteria specifications; 4) co-segregation criteria specifications; and 5) specific use and thresholds for in silico prediction tools, among others.ConclusionEstablishment of these guidelines as the new standard in the clinical laboratory setting will result in a more evidence-based, harmonized method for LDLR variant classification worldwide, thereby improving the care of FH patients.

Purpose: Heritable thoracic aortic disease can result from null variants in MYLK, which encodes myosin light-chain kinase (MLCK). Data on which MYLKmissense variants are pathogenic and information ...

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disorder caused by mutations in ENG, ACVRL1 and SMAD4, which function in regulating the transforming growth factor beta and bone morphogenetic protein signaling pathways. Symptoms of HHT can be present in individuals who test negative for mutations in these three genes indicating other genes may be involved. In this study, we tested for mutations in two genes, RASA1 and GDF2, which were recently reported to be involved in vascular disorders. To determine whether RASA1 and GDF2 have phenotypic overlap with HHT and should be included in diagnostic testing, we developed a next-generation sequencing assay to detect mutations in 93 unrelated individuals who previously tested negative for mutations in ENG, ACVRL1 and SMAD4, but were clinically suspected to have HHT. Pathogenic mutations in RASA1 were identified in two samples (2.15%) and a variant of unknown significance in GDF2 was detected in one sample. All three individuals experienced epistaxis with dermal lesions described in medical records as telangiectases. These results indicate that the inclusion of RASA1 and GDF2 screening in individuals suspected to have HHT will increase the detection rate and aid clinicians in making an accurate diagnosis.