title: Severe classical congenital muscular dystrophy and merosin expression.
abstract: It has been suggested that patients with autosomal recessive merosin deficient congenital muscular dystrophy (CMD), as opposed to the merosin positive cases form a homogeneous subgroup of a clinically more severe form of CMD. We examined merosin expression in muscle biopsies from five children with the severe classical form of CMD. Merosin deficiency was found only in 1 patient, a 6-year-old female, with abnormal brain myelination. However, her initial biopsy did not reveal the classical picture of dystrophy. The four merosin positive cases exhibited severe muscle weakness but their brain imagings were normal. There were no familial cases, except for the mother of 1 patient who had a milder form of the disease, suggesting an autosomal dominant mode of inheritance. In contrast to previous reports, the merosin deficient CMD cases were rare in our group. Furthermore, merosin positive cases were also associated with severe phenotype suggesting that a severe phenotype is not exclusive to merosin deficient cases. Finally, the absence of merosin in a neonate with hypotonia and weakness can be helpful in making a definitive diagnosis of CMD, even though the dystrophic process may not be evident yet and histology may be non-specific.
authors.affiliation: Division of Neurology, The Hospital for Sick Children and the University of Toronto, Ont., Canada.
authors.forename: J
authors.initials: J
authors.lastname: Vajsar
authors.forename: D
authors.initials: D
authors.lastname: Chitayat
authors.forename: L E
authors.initials: LE
authors.lastname: Becker
authors.forename: M
authors.initials: M
authors.lastname: Ho
authors.forename: B
authors.initials: B
authors.lastname: Ben-Zeev
authors.forename: V
authors.initials: V
authors.lastname: Jay
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D007797:Laminin / Q000096:biosynthesis* / Q000172:deficiency; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D009136:Muscular Dystrophies / Q000151:congenital* / Q000378:metabolism / Q000473:pathology
chemical_list: D007797:Laminin