NCIt synonyms : PMC; Paramyotonia Congenita of von Eulenburg;
NCIt definition : An autosomal dominant inherited non-dystrophic myotonia caused by mutations of the
SCN4A gene, resulting in sodium muscle channelopathy. It is characterized by muscle
stiffness, which is increased by exposure to cold or activity, and usually eases when
the patient warms up through physical activity.;