GNE
myopathy is a rare and mildly progressive autosomal recessive
myopathy caused by GNE mutations. Respiratory dysfunction has not been reported in GNE
myopathy patients. In this study, we retrospectively reviewed the respiratory function of 39 severely affected GNE
myopathy patients (13 men, 26 women) from medical records, and compared these parameters with various other patient characteristics (e.g., GNE mutations, age at onset,
creatine kinase levels, and being wheelchair-bound) for correlations. The mean % forced vital capacity [FVC] was 92 (26) (range, 16-128). In 12/39 (31%) patients, %FVC was <80%. Of these 12 patients, 11 (92%) were entirely wheelchair-dependent. These patients exhibited significantly earlier onset (20 [4] vs. 30 [8] years, p<0.001) and lower
creatine kinase levels (56 [71] vs. 279 [185] IU/L) than patients with normal respiratory function. Two patients exhibited severe
respiratory failure and required non-invasive
positive pressure ventilation. Patients with a homozygous mutation in the
N-acetylmannosamine kinase domain exhibited lower %FVC, while only one compound heterozygous patient with separate mutations in the uridinediphosphate-
N-acetylglucosamine 2-epimerase and the
N-acetylmannosamine kinase domains had respiratory dysfunction. Our results collectively suggest that GNE
myopathy can cause severe
respiratory failure. Respiratory dysfunction should be carefully monitored in patients with advanced GNE
myopathy characterized by early onset and homozygous homozygous mutations in the
N-acetylmannosamine kinase domain.