Clinical validity of congenital myopathy genes determined by the ClinGen Congenital Myopathies Expert Panel.

Background: Congenital myopathies are a group of neuromuscular disorders that typically present at birth or early childhood with hypotonia and non-progressive or slowly progressive muscle weakness. They are classically subclassified by characteristic structural changes and histopathological findings in skeletal muscle. Variants in over 40 genes have been described to date in patients with various forms of congenital myopathy with overlapping phenotypic and histological features, which poses a challenge for laboratories and clinicians in interpreting genetic findings.

Objective: The purpose of this study was to evaluate the evidence supporting each gene-disease relationship and provide an expert-reviewed classification for the clinical validity of genes involved in congenital myopathies.

Methods: The ClinGen Neurological Disorders Clinical Domain Working Group assembled the Congenital Myopathies Gene Curation Expert Panel (CongenMyopathy-GCEP), a group of clinicians and geneticists with expertise in congenital myopathies tasked to perform evidence-based curation of 50 gene-disease relationships using the ClinGen semiquantitative framework to assign clinical validity.

Results: Our curation effort resulted in 35 (70%) Definitive, eight (16%) Moderate, six (12%) Limited, and one (2%) Disputed disease relationship classifications. The summary of each curation is made publicly available on the ClinGen website.

Conclusions: Expert-reviewed assignment of gene-disease relationships by the CongenMyopathy-GCEP facilitates accurate molecular diagnoses for congenital myopathies and can allow genetic testing to focus on genes with a validated role in disease.