Heterozygous mutations affecting the epimerase domain of the GNE gene causing distal myopathy with rimmed vacuoles in a Taiwanese family

OBJECTIVES: Studies of distal myopathy with rimmed vacuoles (DMRV) revealed that most patients had mutations in the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene. However, the correlation between GNE mutations and clinical features was not fully understood. PURPOSES: To report the correlation between the clinical features and genetic analysis of DMRV patients. PATIENTS AND METHODS: The clinical presentations, histopathological findings, image studies, and genetic analyses of two patients with DMRV from a Taiwanese family were studied. RESULTS: Two compound heterozygous mutations, Ile 241 Ser and Arg 246 Gln, located in the epimerase domain, were identified in both patients, who were of the same generation. In addition, the elder sister showed a progressive muscular dystrophy course with severe quadriceps and trunk muscle involvement. CONCLUSION: The compound heterozygous mutations in the epimerase domain of the GNE gene are important in the severe phenotype of DMRV. However, the mechanisms leading to this phenotypic heterogeneity still remain to be elucidated.