MYOTONIC DYSTROPHY- DMPK GENE REPEAT EXPANSION ANALYSIS (O.S.)

Overview

Myotonic dystrophy is an autosomal dominant disorder characterized mainly by muscular dystrophy, cataracts, hypogonadism, frontal balding, and ECG changes. Myotonic dystrophy Type 1 (DM1), has a severe congenital form and a milder childhood-onset form as well as an adult-onset form. The genetic defect in DM1 results from an amplified trinucleotide repeat in the 3-prime untranslated region of DMPK gene. Disease severity varies with the number of repeats: normal individuals have 5 to 37 repeats, mildly affected persons have 50 to 150 repeats, patients with classic DM have 100 to 1000 repeats, and those with congenital onset can have more than 2000 repeats.