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Limb‐girdle muscular dystrophies – from genetics to molecular pathology
Author(s) -
Laval S. H.,
Bushby K. M. D.
Publication year - 2004
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/j.1365-2990.2004.00555.x
Subject(s) - limb girdle muscular dystrophy , biology , muscular dystrophy , dysferlin , dystrophin , titin , microbiology and biotechnology , genetics , myopathy , pathology , phenotype , medicine , myocyte , gene , sarcomere
The limb‐girdle muscular dystrophies are a diverse group of muscle‐wasting disorders characteristically affecting the large muscles of the pelvic and shoulder girdles. Molecular genetic analyses have demonstrated causative mutations in the genes encoding a disparate collection of proteins involved in all aspects of muscle cell biology. Muscular dystrophy includes a spectrum of disorders caused by loss of the linkage between the extracellular matrix and the actin cytoskeleton. Within this are the forms of limb‐girdle muscular dystrophy caused by deficiencies of the sarcoglycan complex and by aberrant glycosylation of α‐dystroglycan caused by mutations in the fukutin‐related protein gene. However, other forms of this disease have distinct pathophysiological mechanisms. For example, deficiency of dysferlin disrupts sarcolemmal membrane repair, whilst loss of calpain‐3 may exert its pathological influence either by perturbation of the IκBα/NF‐κB pathway, or through calpain‐dependent cytoskeletal remodelling. Caveolin‐3 is implicated in numerous cell‐signalling pathways and involved in the biogenesis of the T‐tubule system. Alterations in the nuclear lamina caused by mutations in laminA/C, sarcomeric changes in titin, telethonin or myotilin at the Z‐disc, and subtle changes in the extracellular matrix proteins laminin‐α2 or collagen VI can all lead to a limb‐girdle muscular dystrophy phenotype, although the specific pathological mechanisms remain obscure. Differential diagnosis of these disorders requires the careful application of a broad range of disciplines: clinical assessment, immunohistochemistry and immunoblotting using a panel of antibodies and extensive molecular genetic analyses.

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