Inherited neuromyotonia as a phenotypic variation associated with a new mutation in the KCNQ2 gene

Abstract

Background: Neuromyotonia is a disorder of peripheral nerve hyperexcitability (PNH) characterized by muscle cramps, stiffness, myokymia, delayed muscle relaxation after contraction, and hyperhidrosis. Usually cause of neuromyotonia was acquired autoimmune mechanisms against voltage-gated potassium-channel and rare cause was genetic disorders of potassium channels. Mutations are reported mostly in the KCNA1 gene and only one inherited PNH-associated mutation has been described in KCNQ2 (p.Arg207Trp).