Abstract
Background GNE myopathy is a rare autosomal recessive disease caused by mutation in the GNE gene, also known as quadriceps sparing myopathy or hereditary inclusion body myopathy. The estimated worldwide prevalence is 1/1000,000. There are over 150 mutations known to be causative for GNE myopathy. We describe a case of GNE myopathy with compound heterozygosity for one pathogenic and one novel, likely pathogenic variant in the GNE gene.
Case Report A 32-year-old previously healthy woman of Indian descent was referred to our clinic with progressively worsening waddling gait and weakness in her hands. She was uncertain about where her weakness started first and she had no significant family history. On examination, she had weakness of finger flexion, thumb abduction, hip flexion, knee flexion and ankle dorsiflexion with decreased reflexes and normal sensation. Muscle biopsy suggested hereditary inclusion body myopathy and it was confirmed by neuromuscular panel showing heterozygous C.2179G>A (12p.val727Met); C.1368C>A (7p.Ser456Arg) in the GNE gene. She was referred to orthopaedics for foot splints, physiotherapy for muscle strengthening and occupational therapy for impaired hand function. Her condition remained stable at present.
Conclusion GNE myopathy is a rare distal myopathy due to variants in GNE gene. While C.2179G>A being a common variant in Indian population, C.1368C>A is a novel variant likely causative for the disease. Currently there is no disease modifying therapy and management is centred around supportive therapies to improve quality of life. The understanding of genetic variants and associated pathology may provide a revenue to disease modifying therapies.
