Novel missense variants associated with GNE myopathy

GNE myopathy is a rare autosomal recessive skeletal muscle disorder characterized by progressive distal muscle weakness, typically starting in the lower legs and gradually involving proximal muscle groups. It is an autosomal recessive disease, caused by biallelic variants in GNE. To date, over 350 causative GNE variants have been reported, however, establishing genotype-phenotype correlation remains difficult due to clinical heterogeneity and limited patient numbers. In this study, we describe 20 unrelated European families with a diagnosis of GNE myopathy and biallelic GNE variants identified in either homozygosity or compound heterozygosity. While the majority of variants observed in our cohort have been previously reported, we identified five novel missense variants: p.(G355R), p.(A679T), p.(I709T), p.(V727G), and p.(V744I). Using in silico prediction tools and ACMG/ AMP criteria, we classified p.(G355R) and p.(V727G) as likely pathogenic. The clinical features of our cohort were consistent with the classical presentation of GNE myopathy. Our findings contribute new genotype data and support ongoing efforts to refine variant interpretation in GNE myopathy. This study expands the mutational spectrum of GNE and reinforces the phenotypic consistency across diverse populations.