Myotonia congenita (MC) is a skeletal muscle channelopathy characterized by inability of the muscle to relax following voluntary contraction.
myotonia Congenita is associated with functional defects in chloride channels and mutations in a skeletal muscle chloride channel (CLCN1), which encodes for the most abundant chloride channel in the skeletal muscle cell membrane.
Clinical symptoms include restricted jaw opening, halitosis, varying degrees of gingivitis, pseudoptyalism, marked dental calculus accumulation with palpable loose teeth and evidence of poor grooming habits. Severe muscle hypertrophy was found along the cervical spine, proximal aspects of all limbs and the tongue, which protruded from the mouth, hard-to-open mandible. Often, trouble swallowing, as well as observed excessive salivation.