Congenital muscular dystrophy type 1A with residual merosin expression

Abstract

Congenital muscular dystrophy type 1A (MDC1A) is an autosomal recessive disorder characterizedby hypotonia, elevated serum creatine kinase level, delayed motor milestones, white matter changesobserved by brain magnetic resonance imaging, and normal intelligence. A mutation in the laminin α2(LAMA2 ) gene, located at 6q22-23, is a genetic cause of MDC1A. Patients have merosin (laminin α2)-deficient skeletal muscles. However, the degree of merosin expression ranges from total absence topartial reduction. Patients with residual merosin expression have more variable and milder phenotypesthan those with absolute merosin deficiency. We observed a Korean girl with MDC1A with residualmerosin expression. Clinical presentation of this patient was typical except for late onset of the diseaseand external capsule involvement. Immunohistochemical staining of muscle fibers including merosin, isimportant to evaluate patients with hypotonia, delayed motor development, and abnormal white matterchanges.