Clinical, genetic, and pathological characterization of GNE myopathy in China.

Background: GNE myopathy is the most common distal myopathy in China. We summarized the clinical, genetic, and pathological characteristics of 125 Chinese patients with GNE myopathy.

Methods: We collected clinical data of 21 patients diagnosed at our hospital and 104 patients from previous reports. Clinical, genetic, and pathological characteristics were summarized. According to the location of mutations, patients were classified into groups to analyze genotype-phenotype correlation. We reviewed the pathological features and studied the expressions of neural cell adhesion molecule.

Results: The severity of involvement of lower limb muscles was in the following order: tibialis anterior > biceps femoris > gastrocnemius > iliopsoas > quadriceps femoris. Mutation p.D207V was the most common variant in China. Patients carrying p.D207V tended to show later disease onset. In the epimerase/epimerase group, men had earlier disease onset than women (p < 0.05). In other groups, age at disease onset in females was earlier than that in males. Protein analysis showed decreased sialylation of NCAM and upregulation of LC3 in patients with different mutations.

Conclusions: Mutation p.D207V is the most common GNE variant in China. Involvement of flexor muscles in lower limbs was more obvious than extensor muscles. NCAM expression in patients with various mutations may be a useful diagnostic biomarker in GNE myopathy.