A Japanese patient with distal myopathy with rimmed vacuoles: missense mutations in the epimerase domain of the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene accompanied by hyposialylation of skeletal muscle glycoproteins

Abstract

Hereditary inclusion body myopathy and distal myopathy with rimmed vacuoles are both caused by mutations of the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene. Here we report a Japanese patient with compound heterozygous missense mutations in the epimerase domain of GNE gene, 89 G to C and 578 A to T. Biochemical analysis demonstrated decreased reactivity of skeletal muscle glycoproteins with the lectins recognizing sialic acid residues. The results suggest that hyposialylation of glycoproteins may be involved in the pathogenesis of muscle dysfunction in this patient.