What causes Myotonic dystrophy ?
What causes myotonic dystrophy? Myotonic dystrophy is caused by mutations called nucleotide repeat expansions in either the DMPK gene (in type 1) or the CNBP gene (in type 2). Nucleotide repeat expansions occur when a piece of DNA is abnormally repeated a number of times, which makes the gene unstable. In myotonic dystrophy, the gene instability leads to a series of events that ultimately prevent cells in muscles and other tissues from acting normally, leading to the features of the condition. The exact functions of these genes in not well understood. The DMPK gene may play a role in communication within cells, specifically in cells of the heart, brain, and skeletal muscles. The CNBP gene gives directions to make a protein found mainly in cells of the heart and skeletal muscles, where it is thought to regulate the activities of other genes.