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Synonyms of Dystrophy, Myotonic
- Curschmann-Batten-Steinert syndrome
- dystrophia myotonia
- myotonia atrophica
- Steinert disease
- myotonic dystrophy type 1 (DM1)
- myotonic dystrophy type 2 (DM2)
Myotonic dystrophy type 1 (DM1) is an autosomal dominant, multi-system disorder that affects both smooth and skeletal muscles and may affect the central nervous system, heart, eyes, and/or endocrine systems. There are three types of DM1 that are distinguished by the severity of disease and age of onset. Mild DM1 is characterized by cataracts and sustained muscle contractions (myotonia). Classic DM1 is characterized by muscle weakness and wasting (atrophy), cataracts, myotonia and abnormalities in the heart's conduction of electrical impulses. Congenital DM1 is characterized by muscle weakness (hypotonia), difficulty breathing, mental retardation and early death.
DM1 is caused by an abnormality in the DMPK gene. Affected individuals have an increased number of copies of a portion of this gene called CTG. The greater the number of repeated copies of CTG, the more severe the disorder.
Myotonic dystrophy type 2 (DM2), formerly called proximal myotonic myopathy (PROMM) is an autosomal dominant disorder with symptoms that are similar to DM1, but tend to be milder and more variable than DM1. DM2 is an autosomal dominant genetic disorder caused by an abnormality in the ZNF9 gene on chromosome 3q. Affected individuals have an increased number of copies of a portion of this gene.
Dystrophy, Myotonic Resources
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