Myotonia congenita is an inherited condition that affects muscle relaxation. It is congenital, meaning that it is present from birth.
The two major types of myotonia congenita are known as Thomsen disease and Becker disease. These conditions are distinguished by the severity of their symptoms and their patterns of inheritance.
Abnormal repeated electrical signals occur in the muscles, causing a stiffness called myotonia.
Although myotonia can affect any skeletal muscles, including muscles of the face and tongue, it occurs most often in the legs. Myotonia causes muscle stiffness that can interfere with movement. In some people the stiffness is very mild, while in other cases it may be severe enough to interfere with walking, running, and other activities of daily life. These muscle problems are particularly noticeable during movement following a period of rest. Many affected individuals find that repeated movements can temporarily alleviate their muscle stiffness, a phenomenon known as the warm-up effect.
Myotonia congenita has been estimated to occur once in every 100,000 people worldwide. What genes are related to myotonia congenita?
Facts about Myopathies