Myotonia congenita autosomal dominant
Type of disease: Rare conditions
Myotonia congenita is a genetic condition characterized by the inability of the skeletal muscles to quickly relax after a voluntary movement. The symptoms associated with the condition typically appear in childhood and vary from person to person. There are two forms of the disorder: Becker type, which is the most common form; and Thomsen disease, which is a rare and milder form. Both conditions are caused by mutations in the CLCN1 gene. However, the conditions have different modes of inheritance. The Becker type is inherited in an autosomal recessive fashion, and the Thomsen type is inherited in an autosomal dominant manner. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.