Merosin Deficient Congenital Muscular Dystrophy in Korea

ABSTRACT

PURPOSES:Congenital muscular dystrophies(CMDs) are an autosomal recessive and heterogeneous disorders. The classic forms of CMD are subclassified into two major categoriesmerosin positive and deficient. Merosin deficient congenital muscualr dystrophy (MDCMD) is rare in Asia and it has never been reported especially in Korea. So, we summarized the clinical features with neuroimaging findings of the patients, who were diagnosed as MDCMD, for the first time in Korea. METHODS: Twenty three patients were diagnosed as CMD in Seoul National University Children's Hospital over 3 years(2001-2004). Among them, four patients with MDCMD were proven by merosin immunohistochemical staining. We reviewed their clinical, pathologic features, EMG/NCS findings and brain MRIs. RESULTS: Among 23 patients with CMD, 4 patients(17.4%) were MDCMD. All of them were presented at birth or early infancy with hypotonia, muscle weakness and joint contracture. They all could not walk and had myopathic faces, developmental delay, poor weight gain and scoliosis. EMG/NCS showed myopathic motor unit action potential (MUP) and decreased compound motor unit action potential(CMAP). Merosin deficiency was demonstrated in muscle or skin tissues. All of them had diffuse or focal high signal intensity lesions of white matter in brain MR T2WI. However, they showed neither mental retardation nor seizure though one of them had right occipital polymicrogyria. CONCLUSION: We reported 4 children with MDCMD for the first time in Korea. The prevalence in Korea might be lower than in Europe but probably higher than in Japan. If CMD patients have sustained delayed motor milestone with normal intelligence, myopathic face, decreased CMAP and myopathic MUP in EMG/NCS, MDCMD should be suspected and further diagnostic work up such as brain MR and merosin immunohistochemistry will be needed.