Nystagmus is an eye movement disorder in which one or both eyes are in constant movement. Nystagmus that occurs independent of these known ocular or systemic diseases is referred to as congenital motor nystagmus (CMN) or idiopathic congenital nystagmus (ICN). It can be inherited as an autosomal dominant, an autosomal recessive, or an X-linked trait. At least six genetic loci for CMN have been suggested, including three loci for autosomal dominant CMN, and three loci for X-linked CMN. A variety of mutations in the FRMD7 gene have been identified in many families with an X-linked recessive pattern. Another mutation associated with X-linked CMN is GPR143.
