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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Limb-girdle Muscular Dystrophy (LGMD) is a rare form of muscular dystrophy inherited as an autosomal recessive trait. The LGMD locus was recently mapped to chromosome 15. We tested the hypothesis that fibrillin is a candidate in the etiology of the disorder by genetic linkage analysis. A large Amish kindred segregating the disorder was genotyped for two markers specific for the fibrillin gene on chromosome 15. A total of 105 individuals were genotyped and a maximum LOD score of Z = 9. 135 at theta = 0.04 was obtained. Our results confirmed the mapping of the LGMD on chromosome 15 and excluded fibrillin as a candidate molecule. These data will be useful in the construction of a fine map of the region surrounding the LGMD locus, a prerequisite for the cloning of the LGMD gene.
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PMID:Limb-girdle muscular dystrophy is closely linked to the fibrillin locus on chromosome 15. 833 42

Fibrillins are large extracellular macromolecules that polymerize to form the backbone structure of connective tissue microfibrils. Mutations in the gene for fibrillin-1 cause the Marfan syndrome, while mutations in the gene for fibrillin-2 cause Congenital Contractural Arachnodactyly. Both are autosomal dominant disorders, and both disorders affect musculoskeletal tissues. Here we show that Fbn2 null mice (on a 129/Sv background) are born with reduced muscle mass, abnormal muscle histology, and signs of activated BMP signaling in skeletal muscle. A delay in Myosin Heavy Chain 8, a perinatal myosin, was found in Fbn2 null forelimb muscle tissue, consistent with the notion that muscle defects underlie forelimb contractures in these mice. In addition, white fat accumulated in the forelimbs during the early postnatal period. Adult Fbn2 null mice are already known to demonstrate persistent muscle weakness. Here we measured elevated creatine kinase levels in adult Fbn2 null mice, indicating ongoing cycles of muscle injury. On a C57Bl/6 background, Fbn2 null mice showed severe defects in musculature, leading to neonatal death from respiratory failure. These new findings demonstrate that loss of fibrillin-2 results in phenotypes similar to those found in congenital muscular dystrophies and that FBN2 should be considered as a candidate gene for recessive congenital muscular dystrophy. Both in vivo and in vitro evidence associated muscle abnormalities and accumulation of white fat in Fbn2 null mice with abnormally activated BMP signaling. Genetic rescue of reduced muscle mass and accumulation of white fat in Fbn2 null mice was accomplished by deleting a single allele of Bmp7. In contrast to other reports that activated BMP signaling leads to muscle hypertrophy, our findings demonstrate the exquisite sensitivity of BMP signaling to the fibrillin-2 extracellular environment during early postnatal muscle development. New evidence presented here suggests that fibrillin-2 can sequester BMP complexes in a latent state.
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PMID:Abnormal Activation of BMP Signaling Causes Myopathy in Fbn2 Null Mice. 2611 82