myotonic dystrophy
Also written as: DM — myotonic dystrophy
An inherited multisystem disorder characterized by progressive muscle weakness and delayed muscle relaxation (myotonia).
Full Definition
Myotonic dystrophy is the most common form of adult-onset muscular dystrophy, characterized by progressive muscle weakness, myotonia (delayed muscle relaxation), and multisystem involvement. Two main types exist: type 1 (DM1) caused by CTG repeat expansions in the DMPK gene, and type 2 (DM2) caused by CCTG repeat expansions in the CNBP gene. Clinical features include distal weakness, facial weakness, cataracts, cardiac conduction abnormalities, and endocrine dysfunction. DM1 typically presents earlier with more severe symptoms than DM2. Diagnosis is confirmed through genetic testing, and management focuses on symptomatic treatment and monitoring for cardiac complications.
Usage
Usage note: Also known as Steinert disease; specify type (DM1 or DM2) when known.
In Context
- "The patient's myotonic dystrophy required regular cardiac monitoring for conduction abnormalities." — Cardiology consultation
- "Genetic testing confirmed DM1 with an expanded CTG repeat in the myotonic dystrophy gene." — Genetics report