Novel GNE compound heterozygous mutations in a GNE myopathy patient

Abstract

Introduction: Molecular studies have revealed that some patients with myopathies with rimmed vacuoles have pathogenic mutations in the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) and Z-band alternatively spliced PDZ motif-containing protein (ZASP) genes.

Methods: We investigated a patient with distal myopathy with rimmed vacuoles by muscle biopsy and sequenced 6 candidate genes.

Results: The patient carried GNE compound heterozygous missense mutations (p.V421A and p.N635K) and a ZASP variant (p.D673N). This patient also presented with distal weakness sparing the quadriceps muscles and had atypical results for Z-band-associated protein immunostaining. This finding indicates that the GNE mutations are pathogenic, and the diagnosis is compatible with GNE myopathy.

Conclusions: By combining pathological studies and candidate gene screening, we identified a patient with GNE myopathy due to novel GNE compound heterozygous mutations.

Keywords: GNE myopathy; UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE); Z-band alternatively spliced PDZ motif-containing protein (ZASP); distal myopathy with rimmed vacuoles; myofibrillar myopathy.