Myotonia Congenita, Autosomal Dominant, also known as myotonia levior, is related to myotonia congenita, autosomal recessive and myotonia, and has symptoms including muscular stiffness and lid lag. An important gene associated with Myotonia Congenita, Autosomal Dominant is CLCN1 (Chloride Voltage-Gated Channel 1). Affiliated tissues include skeletal muscle and tongue, and related phenotypes are myotonia with warm-up phenomenon and myotonia