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CMD Overview
The congenital muscular dystrophies represent a group of diseases causing muscle weakness at birth. Several defined genetic mutations cause muscles to break down faster than they can repair or grow. A person with CMD may have various neurological or physical impairments. Some never gain the ability to walk, while others lose the ability as they grow older.
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Video: Overview of Congenital Muscular Dystrophy by Dr. Jim Collins
The 5 Primary Subtypes of Congenital Muscular Dystrophy
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Collagen 6 (Ullrich CMD, Intermediate COL6, Bethlem Myopathy)
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α-Dystroglycanopathy (Walker-Warburg, Fukuyama, Muscle-Eye-Brain, LGMD: 2I/R9, 2K/R11, 2M/R13, 2N/R14, 2O/R15, 2T/R19, 2U/R20, R24)
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LAMA2 (Merosin Deficient, Merosin Negative)
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LMNA (L-CMD, Laminopathy, Emery-Dreifuss MD)
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SELENON/SEPN1 (Rigid Spine MD, Multi-Minicore Disease)
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Video: Genetic Diagnoses of CMD by Sandra Donkervoort, MS, CGC
Physiology
The CMDs involve proteins in four locations of the muscle cell. Mutations in any of these proteins account for some form of muscular dystrophy.
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The extracellular matrix proteins
(COL6, LAMA2) -
the glycosyltransferase proteins: proteins that place a sugar on the alpha dystroglycan
(α-Dystroglycanopathies) -
intracellular protein deficiency
(SELENON) -
intranuclear intermediate filament deficiency (LMNA)
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