Merosin-positive congenital muscular dystrophy in two siblings with cataract and slight mental retardation

We report on two siblings that have been followed for 14 years, with merosi n-positive congenital muscular dystrophy (CMD), cataract, retinitis pigment osa, dysversion of the optic disc, but no cerebral anomalies, except for mi crocephaly and slight mental retardation (MR). The younger child had three generalized seizures easily controlled by anticonvulsant therapy. Both chil dren presented hypotonia from birth, delayed psychomotor development, gener alized muscular weakness, and atrophy aid joint contractures of knees and a nkies. The course of the disease, apparently static during the first 10 yea rs of life, became progressive during the second decade with loss of deambu lation by the age of 13. Creatine kinase was increased in both children. Bi lateral cataract was diagnosed at 6-months of age. In spite of the occurren ce of microcephaly, MR was slight and the siblings acquired reading and wri ting skills after the aged 10. I-lead magnetic resonance imaging showed nor mal results in both siblings. The classification of these cases within the broad spectrum of CMD is difficult since most of the known muscle-eye-brain syndromes generally show severe MR and brain anomalies. We consider these cases as corresponding to the rarer syndromes of merosin-positive CMD with associated features such as cataract and MR that were particularly emphasiz ed during the 50th ENMC International Workshop on CMD Further genetic, path ological, neuroradiological,, and immunocytochemical studies will be necess ary for better elucidation of the classification and pathogenesis of CMD. ( C) 1999 Elsevier Science B.V. All rights reserved.