GNE myopathy in Chinese population: hotspot and novel mutations.

ABSTRACT

GNE myopathy is a rare autosomal recessive distal myopathy caused by mutations in UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), the bi-functional enzyme critical for sialic acid biosynthesis. In this study, we summarized the clinical features, pathological characteristics, and genetic profiles of 46 GNE patients. The clinical and mutational profile of 54 previously reported Chinese patients were also reviewed. A total of 21 novel mutations, including a gross deletion spanning exon 1-2 and a retrotransposon insertion were found in our cohort, enlarging the spectrum of GNE mutations. The most frequent mutation in Chinese population was D207V, which accounts for 25.5% of total alleles (51/200). The age of onset was much later in the patients carrying D207V compared to other patients, indicated the less deleterious effect of D207V on enzyme activity. GNE myopathy may be overlooked in China with a relatively milder phenotype due to the common mutation D207V.