Challenges in genetic counseling for RYR1-related myopathies

Abstract

Background: Ryanodine receptor 1 (RYR1)-related myopathy is inherited in an autosomal dominant (AD) or recessive (AR) manner. We experienced two sporadic cases of RYR1-related myopathy. One patient harbored a de novo missense variant, whereas the other harbored compound heterozygous variants inherited from each parent. The possibility of dual inheritance makes it challenging to distinguish between these two inheritance patterns based only on clinical information.

Methods: In this study, PubMed was used to perform literature review on genetic counseling for RYR1-related myopathy.

Results: Recently published manuscripts have emphasized the importance of comprehensive genomic analysis of all RYR1 coding regions.

Conclusion: RYR1-related myopathy without family history may be associated with de novo heterozygous AD variants and biallelic involvement in AR. In cases of AR traits, a prenatal diagnosis may be required from the parents. Therefore, precise genetic information is essential for genetic counseling. It would be impossible to assess the inheritance patterns from genotypes only if monoallelic missense variants were identified in patients with congenital myopathy. This review emphasizes the importance of comprehensively analyzing all coding regions using trio samples for better genetic counseling.

Keywords: Dual inheritance; Genetic counseling; Muscle MRI; Next-generation sequencing (NGS); RYR1-related myopathy.