一過性の筋力低下から回復し，10年間無症状であるdysferlin異常症の1例

Abstract

We report a 28-year-old male with dysferlinopathy, who has remained asymptomatic for 10 years from a rhabdomyolysis-like episode. He had been in good health since birth, but felt difficulty in walking after a month and a half of manual labor at 18 years old (at the year 2000). Rhabdomyolysis was suspected because of muscle weakness and elevated serum CK of 28,094U/L. He was hospitalized and his muscle weakness improved. He was referred to us, because his serum CK remained around 2,000U/L. Histological analysis of muscle, when anti-dysferlin antibody was unavailable, was not informative but later analysis at the age of 23 using preserved specimen showed loss of dysferlin immunoreactivity. Subsequently, a missense mutation (c.2997G>T) and a deletion (c.3373delG) of the dysferlin gene, both of which are common in Miyoshi myopathy in Japanese, were identified. He continuously showed hyper-CKemia, but no apparent muscle weakness emerged for more than ten years. Reports on asymptomatic dysferlinopathy over such a long duration are rare. This case may suggest that genetic factors, environmental factors such as intensity of work-load, or both, might affect the clinical course of dysferlinopathy. Further follow-up is necessary.