Myotonic dystrophy type 1 (DM1): A triplet repeat expansion disorder

•Myotonic dystrophy (DM) affects about 1 in 8000 people worldwide.•The correlation between CTG repeat sizes matches the severity of the disease.•Different molecular mechanisms involve in myotonic dystrophy disease progression.•Clinical and molecular diagnosis is used for screening of CTG repeat in DM1.•Modafinil drug, antisense therapy etc. involve in therapeutics, management of DM1.

Myotonic dystrophy is a progressive multisystem genetic disorder affecting about 1 in 8000 people worldwide. The unstable repeat expansions of (CTG)n or (CCTG)n in the DMPK and ZNF9 genes cause the two known subtypes of myotonic dystrophy: (i) myotonic dystrophy type 1 (DM1) and (ii) myotonic dystrophy type 2 (DM2) respectively. There is currently no cure but supportive management helps equally to reduce the morbidity and mortality and patients need close follow up to pay attention to their clinical problems. This review will focus on the clinical features, molecular view and genetics, diagnosis and management of DM1.