The myopathies are neuromuscular disorders in which the primary symptom is muscle weakness due to dysfunction of muscle fiber.
Other symptoms of myopathy can include include muscle cramps, stiffness, and spasm. Myopathies can be inherited (such as the
muscular dystrophies) or acquired (such as common muscle cramps). Myopathies are grouped as follows:
congenital myopathies: characterized by developmental delays in motor skills; skeletal and facial abnormalities are occasionally evident at birth
muscular dystrophies: characterized by progressive weakness in voluntary muscles; sometimes evident at birth
mitochondrial myopathies: caused by genetic abnormalities in mitochondria, cellular structures that control energy; include Kearns-Sayre syndrome,
MELAS and MERRF
glycogen storage diseases of muscle: caused by mutations in genes controlling enzymes that metabolize glycogen and glucose (blood sugar); include Pompe's, Andersen's
and Cori's diseases
myoglobinurias: caused by disorders in the metabolism of a fuel (myoglobin) necessary for muscle work; include McArdle, Tarui, and DiMauro
diseases
dermatomyositis: an inflammatory myopathy of skin and muscle
myositis ossificans: characterized by bone growing in muscle tissue
familial periodic paralysis: characterized by episodes of weakness in the arms and legs
polymyositis, inclusion body myositis, and related myopathies: inflammatory myopathies of skeletal muscle
neuromyotonia: characterized by alternating episodes of twitching and stiffness; and
stiff-man syndrome: characterized by episodes of rigidity and reflex spasms
common muscle cramps and stiffness, and
tetany: characterized by prolonged spasms of the arms and legs
National Institute of Arthritis and
Musculoskeletal and Skin Diseases (NIAMS) National Institutes of Health, DHHS 31 Center Dr., Rm. 4C02 MSC 2350 Bethesda, MD 20892-2350 NIAMSinfo@mail.nih.gov http://www.niams.nih.gov Tel: 301-496-8190 877-22-NIAMS (226-4267) |
Muscular Dystrophy Association 3300 East Sunrise Drive Tucson, AZ 85718-3208 mda@mdausa.org http://www.mda.org Tel: 520-529-2000 800-344-4863 Fax: 520-529-5300 |
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Last updated October 28, 2008