Myotonia Congenita is a rare genetic disorder that affects the skeletal muscles. This condition causes muscle stiffness and difficulty in moving after contracting the muscles. There are some synonyms that can be used for Myotonia Congenita, such as Thomsen disease, Becker disease, and Schwartz-Jampel syndrome. Thomsen disease is named after the Danish physician and surgeon Julius Thomsen, who first described this condition in 1876. Becker disease is another form of Myotonia Congenita, which is more severe than Thomsen disease. Schwartz-Jampel syndrome is another synonym for this condition, which is characterized by muscle stiffness, bone deformities, and growth delay.