MEROSIN-NEGATIVE CONGENITAL MUSCULAR-DYSTROPHY ASSOCIATED WITH EXTENSIVE BRAIN ABNORMALITIES

Congenital muscular dystrophies (CMDs) are autosomal recessive, hetero geneous disorders. The most frequent form in the Caucasian population is classic (occidental) CMD, characterized by exclusive muscle involve ment, although abnormal brain white matter signals are occasionally ob served on MRI. Recently, deficiency of merosin, the laminin isoform in skeletal muscle, has been identified in classic CMD patients. In skel etal muscle, merosin is a native ligand for dystroglycan linking the e xtracellular matrix and dystrophin. Thus, merosin deficiency could dis rupt the attachment of muscle cell to the extracellular matrix and lea d to muscle cell necrosis. Since merosin is also expressed in the nerv ous system and has biologic activities on neurite outgrowth and Schwan n cell migration, deficiency of merosin could affect the development o f the nervous system. We report here two patients with merosin-negativ e CMD presenting extensive brain abnormalities characterized by cortic al anomaly, polymicrogyria, and abnormal white matter signals.