Clinical, pathological and genetic characteristics of GNE myopathy: a single-center observational study.

INTRODUCTION

GNE myopathy is a rare autosomal recessive hereditary myopathy resulting in impaired sialic acid biosynthesis. The features of this condition include distal muscle weakness with relatively preserved quadriceps femoris strength and the presence of rimmed vacuoles in muscle fibers.

METHODS

We performed a retrospective clinical analysis of patients diagnosed with GNE myopathy at our hospital from 2017 to 2024.

RESULT: All six patients exhibited weakness in the distal lower limbs. Rimmed vacuoles were observed in the muscle fibers of five patients. Additionally, several relatively uncommon clinical manifestations were identified in this study, including Beevor's sign, respiratory dysfunction, ragged red fibers, and elevated acid phosphatase enzyme activity. Genetic analysis revealed five novel variants in the GNE gene: c.1691G > T (p.G564V), c.1877 C > G (p.A626G), c.935_936insAA (p.H312fs), c.1247 A > T (p.K416M), and c.974 C > T (p.A325V). Furthermore, three patients carried the hotspot variant p.D207V.

CONCLUSION

The clinical and histopathological findings underscore the distinctive characteristics and heterogeneity of the disease. Significantly, this study broadens the mutational spectrum of GNE myopathy by identifying five novel variants.