CLDN11 is a gene that produces the claudin-11 protein. Claudin-11 is a critical structural component of the myelin sheath which is a protective coating for nerves. When the myelin sheath is compromised, the transmission of electrical impulses along the nerves slows down. Disease-causing variants in CLDN11 affect the functioning of the nervous system and cause the clinical manifestations described in the Clinical Characteristics Section.