Novel missense mutation p.A310P in the GNE gene in autosomal-recessive hereditary inclusion-body myopathy/distal myopathy with rimmed vacuoles in an Italian family.

Autosomal-recessive hereditary inclusion-body myopathy with relative quadriceps sparing is associated with mutations in the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene. Two Italian sisters affected with autosomal-recessive hIBM were shown to be compound heterozygous for a novel GNE mutation: a p.A310P amino acid change along with a p.R246W mutation on the second allele both in the epimerase domain. This is the first mutation event observed in a human GNE allele inducing a proline. Muscle biopsy showed abundant rimmed and non-rimmed vacuoles. Severe disease progression was noted in the elder sister. The Italian family further expands the wide phenotypic and genotypic spectrum of hIBM.