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any disorder involving tonic spasm of muscle. adj., adj myoton´ic.
myotonia conge´nita a hereditary disease marked by tonic spasm and rigidity of certain muscles when attempts are made to move them. The stiffness tends to disappear as the muscles are used.
my·o·ton·ic dys·tro·phy [MIM*160900]
the most common adult muscular dystrophy, characterized by progressive muscle weakness and wasting of some of the cranial innervated muscles, as well as the distal limb muscles; other clinical features include myotonia, cataracts, hypogonadism, cardiac abnormalities, and frontal balding; onset usually in the the third decade; autosomal dominant inheritance caused by abnormal trinucleotide repeat expansion in the dystrophia myotonica protein kinase gene (DMPK) on chromosome 19q. This disorder demonstrates anticipation (increase in severity in successive generations because of successive amplification of the trinucleotide repeats); the severe congenital form is almost always confined to the children of affected women.
myotonia (mi?o-to'ne-a) [ myo- + tono- + -ia]
Tonic spasm of a muscle or temporary rigidity after muscular contraction. myotonic (-ton'ik), adjective
myotonia atrophicaMyotonia dystrophica.
A benign disease characterized by tonic spasms of the muscles induced by voluntary movements. The condition is usually congenital and is transmitted by either dominant or recessive genes. Synonym: amyotonia congenita
; myotonic atrophyOppenheim's disease
; Thomsen's disease
The disease appears in early childhood and is manifested by a tonic spasm of the muscles every time the muscles are used. In a few minutes, rigidity wears away, and the movements become free from repeated contractions, the muscles becoming firm and extremely well developed.
Quinine or procainamide are indicated for relief of myotonia. Neostigmine is contraindicated. Avoidance of obesity is important.
The disease is incurable but may improve with age.
A dominantly inherited disease characterized by muscular wasting, myotonia, and cataract. Synonym: myotonia atrophica
; Steinert's disease