Gene analysis and clinical features of 22 GNE myopathy patients

GNE myopathy is an autosomal recessive distal myopathy caused by a biallelic mutation in UDP-N-acetylglucosamine 2-epomerase/N-acetylmannosamine kinase. In this study, we discuss the clinical features, pathological characteristics, genetic profiles, and atypical clinical manifestations of 22 Chinese GNE patients.

Retrospective analysis was performed for GNE myopathy patients at our institute between 2005 and 2021. Histopathological analysis and gene testing were done according to standard protocols.

Molecular analysis revealed 14-reported and 7 novel mutations, including c.125G > A (p.P42Q), c.226G > A (p.V76I), c.970C > G (p.H324D), c.155A > G (p.D52G), c.1055G > A (p.R352H), c.1064G > A (p.G355E), and c.491 T > C (p.I164T) in GNE. D207V was the most frequent mutation showing an allele frequency of 25%. A total of 21 patients presented classic clinical manifestation, and only 1 patient had signs of proximal muscle weakness. A patient containing p.V603L and p.R160X mutations showed idiopathic thrombocytopenia and distal weakness. There were 4 female patients who experienced rapid deterioration after pregnancy.

Our study revealed 7 novel mutations in GNE, where p.D207V was shown as a potential hotspot mutation in Chinese patients. Idiopathic thrombocytopenia should be a concern in GNE myopathy patients. Twenty-seven percent of female patients experienced rapid deterioration during pregnancy or after delivery.