DMPK

About DMPK

DMPK on chromosome 19q13.32 encodes myotonic dystrophy protein kinase, a serine threonine kinase expressed in muscle, heart, and brain. An expansion of a CTG trinucleotide repeat in the untranslated end of the gene causes myotonic dystrophy type 1, the most common adult onset muscular dystrophy. The expanded repeat is transcribed into RNA that forms clumps in the nucleus and sequesters RNA binding proteins such as MBNL1, disrupting the processing of many other genes, a mechanism known as RNA toxicity. Features include myotonia, a delay in muscle relaxation, progressive weakness, cataracts, heart conduction defects, and endocrine and cognitive effects. The repeat tends to lengthen from one generation to the next, a phenomenon called anticipation, and the largest expansions, usually transmitted by mothers, cause a severe congenital form. Myotonic dystrophy type 2 is caused by a different repeat in CNBP.