Mutation in the caveolin-3 gene causes asymmetrical distal myopathy

Mutations in the gene encoding caveolin-3 (CAV3) can cause a broad spectrum of clinical phenotypes, including limb girdle muscular dystrophy, rippling muscle disease, distal myopathy (MD), idiopathic persistent elevation of serum creatine kinase and cardiomyopathy. MD is a relatively rare subtype of caveolinopathy. Here, we report a sporadic case of a middle-aged female Chinese patient with MD in which a CAV3 mutation was identical to that previously reported in cases of rippling muscle disease. T1-weighted enhanced skeletal muscle MRI of the lower limbs showed an abnormal signal in the distal and proximal muscles. A muscle biopsy revealed moderate dystrophic changes, and immunohistochemical staining showed reduced CAV-3 expression in the plasmalemma. Genetic analysis revealed a heterozygous c.136G > A (p.Ala46Thr) CAV3 mutation that appeared to be de novo because it was absent from the patient's parents. This study suggested that the CAV3 c.136G > A (p.Ala46Thr) mutation can cause MD as well as different phenotypes in different individuals, suggesting that additional unknown loci must affect the disease phenotypes.