DNAJB6 myopathy: A vacuolar myopathy with childhood onset

Introduction: DNAJB6 mutations cause an autosomal dominant myopathy that can manifest as limb‐girdle muscular dystrophy (LGMD1D/1E) or distal‐predominant myopathy. In the majority of patients this myopathy manifests in adulthood and shows vacuolar changes on muscle biopsy. Methods: Clinical, electrophysiological, pathological, and molecular findings are reported. Results: We report a 56‐year‐old woman, who, like 3 other family members, became symptomatic in childhood with slowly progressive limb‐girdle muscle weakness, normal serum creatine kinase (CK) values, and myopathic electromyographic findings. Muscle biopsy showed vacuolar changes and congophilic inclusions, and molecular analysis revealed a pathogenic mutation in the DNAJB6 gene. Differences and similarities with previously described cases are assessed. Conclusions: Childhood‐onset of DNAJB6 myopathy is more frequent than previously believed; congophilic inclusions may be present in the muscle of these patients. Muscle Nerve 49:607–610, 2014