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any disease of a muscle. adj., adj myopath´ic.
centronuclear myopathy myotubular myopathy.
distal myopathy an autosomal dominant form of muscular dystrophy, appearing in two types. The first has onset in infancy, does not progress past adolescence, and is not incapacitating. The second has onset in adulthood and is called late distal hereditary myopathy. Called also distal muscular dystrophy.
glycolytic myopathy any metabolic myopathy resulting from a defect of glycolytic enzyme activity, marked by exercise intolerance and cramping, the accumulation of glycogen in muscle, and recurrent myoglobinuria.
late distal hereditary myopathy distal myopathy that sets in usually after age 40, does not affect life span and first affects the small muscles of the hands and feet and then spreads proximally.
metabolic myopathy myopathy due to disordered metabolism, usually caused by genetic defects or hormonal dysfunction.
mitochondrial myopathy any of a group of myopathies associated with an increased number of enlarged, often abnormal, mitochondria in muscle fibers, manifested by exercise intolerance, generalized weakness, lactic acidosis, infantile tetraparesis, ophthalmoplegia, and cardiac abnormalities.
myotubular myopathy a form marked by myofibers resembling the myotubules of early fetal muscle.
nemaline myopathy a congenital abnormality of myofibrils in which small threadlike fibers are scattered through the muscle fibers; marked by hypotonia and proximal muscle weakness.
ocular myopathy a slowly progressive form affecting the extraocular muscles, with ptosis and progressive immobility of the eyes.
slowly progressive generalized muscle weakness and atrophy beginning in childhood; on biopsy of skeletal muscle, the nuclei of most muscle fibers are seen to be located near the center of a small fiber (the normal position for a 10-week embryo) rather than at the periphery of the fiber; familial incidence. Autosomal dominant [MIM*160150] recessive [MIM*255200] and X-linked  forms occur. The X-linked form is caused by mutation in the myotubular myopathy gene (MTM1) on Xq28.
Synonym(s): myotubular myopathy
myotubular myopathyCentronuclear myopathy A myopathy with various patterns of inheritance; all have centrally-located nuclei in muscle fibers, surrounded by cytoplasmic material with features of maturing myotubules, accompanied by atrophy of type I and hypertrophy of type II muscle fibers; the X-linked form results in neonatal death due to respiratory muscle insufficiency; the AD form is benign. See Myopathy.
strictly speaking, any disease of a muscle. Common usage is to restrict its use to describe the noninflammatory degenerations of skeletal muscle characterized by hyaline degeneration of muscle fibers, muscle weakness, myoglobinuria and a high serum level of muscle enzymes. This includes post-exertional rhabdomyolysis, enzootic nutritional muscular dystrophy, congenital myopathies, neurogenic atrophy and pale, soft, exudative pork. See also muscular.
an acute myopathy occurring most frequently in wild animals after a long chase or with a lot of struggling. The course is short and the death rate high. Affected animals are recumbent, dyspneic, hyperthermic and show muscle tremor. It is basically an exertional myopathy.
congenital myotonic myopathy
see myotonia congenita.
equine polysaccharide storage myopathy
(EPSM) a form of exertional rhabdomyolysis that occurs in several breeds but particularly the Quarter horse and draft horse breeds, resulting in muscle tremor and weakness. Affected horses have enhanced glucose storage and glycogen synthesis, elevated muscle glycogen and polysaccharide storage inclusions in type II muscle fibers, but a specific enzyme defect has not been identified.
fibrous adhesions between the muscle masses in the posterior thigh muscles in horses. A sequel to traumatic mysositis. See also ossifying myopathy (below).
Golden retriever myopathy
a congenital disorder of muscles seen from a very young age in male Golden retrievers that show a stiff gait, abduction of thoracic limbs, bunny-hopping in the pelvic limbs, and enlargement of the tongue. The clinical signs worsen with exercise and as the dog matures. Now recognized as an X-linked inherited deficiency of dystrophin, analogous to the human disorder, Duchenne muscular dystrophy.
see feline hypokalemic polymyopathy.
lipid storage myopathy
increased amounts of lipid accumulate in myofibers causing weakness, muscle pain and atrophy and rarely cardiomyopathy. Reported in dogs; the cause is unknown but abnormalities in levels of lactate, pyruvate and carnitine have been found.
caused by a deficiency of pyruvate dehydrogenase; reported in Clumber spaniels, Sussex spaniels and Old English sheepdogs.
a form marked by myofibers resembling those of early fetal muscle, i.e. myotubules.
a rare inherited neuromuscular disease of humans characterized by myotonia and the presence of fine fibrous threads called nemaline rods. Reported in cats.
calcification of the adhesions of fibrotic myopathy. A special occurrence is in the semimembranosus, semitendinosus and biceps femoris muscles of Western performance horses. See ossifying fibrotic myopathy.
see exertion myopathy (above).
after a period of recumbency with general anesthesia, affected horses are usually unable to rise. If they do rise, they show severe tremor, weakness and easy falling. Serum muscle enzyme levels indicate gross muscle damage and both fore- and hindlimbs are affected.