Mutations in genes coding for dystrophin, for alpha, beta, gamma, and delta-sarcoglycans, or for the alpha2 chain of the basement membrane component merosin (laminin-2/4) cause various forms of muscular dystrophy. Analyses of integrins showed an abnormal expression and localization of alpha7beta1 isoforms in myofibers of merosin-deficient human patients and mice, but not in dystrophin-deficient...

Laminin (laminin-1; alpha 1-beta 1-gamma 1) is known to promote myoblast proliferation, fusion, and myotube formation. Merosin (laminin-2 and -4; alpha 2-beta 1/beta 2-gamma 1) is the predominant laminin variant in skeletal muscle basement membranes; genetic defects affecting its structure or expression are the causes of some types of congenital muscular dystrophy. However, the precise nature o...

Congenital muscular dystrophies (CMDs) are autosomal recessive, heterogeneous disorders. The most frequent form in the Caucasian population is classic (occidental) CMD, characterized by exclusive muscle involvement, although abnormal brain white matter signals are occasionally observed on MRI. Recently, deficiency of merosin, the laminin isoform in skeletal muscle, has been identified in classi...

Congenital muscular dystrophies are a group of heterogeneous inherited autosomal recessive disorders. The so-called 'pure' or 'occidental' form is further divided into merosin-positive and merosin-negative subgroups. Merosin is also expressed in the nervous system and its deficiency could affect development of the nervous system. The authors report two siblings with merosin-negative congenital ...

alpha-Dystroglycan, a 156 kDa dystrophin-associated glycoprotein, binds laminin in skeletal muscle. Here we demonstrate that alpha-dystroglycan is a binding protein of laminin (A/B1/B2) and merosin (M/B1/B2) in peripheral nerve. Immunocytochemical analysis demonstrates the localization of alpha-dystroglycan and merosin surrounding myelin sheath of peripheral nerve fibers. Biochemical analysis d...

Congenital muscular dystrophy type 1A (MDC1A) is an autosomal recessive disorder characterized by hypotonia, elevated serum creatine kinase level, delayed motor milestones, white matter changes observed 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)-defic...

Humans and mice with deficiency of the alpha2 subunit of the basement membrane protein laminin-2/merosin suffer from merosin-deficient congenital muscular dystrophy (MCMD). We have expressed a human laminin alpha2 chain transgene under the regulation of a muscle-specific creatine kinase promoter in mice with complete or partial deficiency of merosin. The transgene restores the synthesis and loc...

Merosin-deficient congenital muscular dystrophy type 1A (MDC1A) is the most common form of congenital muscular dystrophy. MDC1A is caused by mutation of the laminin alpha-2 gene (LAMA2), localized to chromosome 6q22-23. The diagnosis of merosin-deficient CMD is based on the clinical findings of severe congenital hypotonia, weakness, with high blood levels of creatine kinase, WM abnormalities, a...

Jannapureddy, Suneal R., Nisha D. Patel, Willy Hwang, and Aladin M. Boriek. Selected Contribution: Merosin deficiency leads to alterations in passive and active skeletal muscle mechanics. J Appl Physiol 94: 2524–2533, 2003; 10.1152/japplphysiol.01078.2002.—The role of extracellular elements on the mechanical properties of skeletal muscles is unknown. Merosin is an essential extracellular matrix...

BACKGROUND AND PURPOSE Our purpose was to determine the brain MR imaging characteristics of merosin-deficient congenital muscular dystrophy in children. METHODS We reviewed the MR imaging findings of the brain in three children with known merosin-deficient congenital muscular dystrophy to determine the presence of any cerebral or cerebellar abnormalities of development or abnormalities of the...