We have identified mutations in an X chromosome-linked, Aristaless-related, homeobox gene (ARX), in nine families with mental retardation (syndromic and nonspecific), various forms of epilepsy, including infantile spasms and myoclonic seizures, and dystonia.
Mutations in the ARX gene are responsible for a wide variety of mental retardation conditions including X-linked infantile spasms (ISSX) and generalized dystonia.
In addition, they might reflect that other phenotypic features associated with CDKL5 mutations (Rett-like features, infantile spasm) or ARX mutations (dystonia, spasticity) are more distinctive.
We screened for both ARX polyA expansions in 98 unrelated patients selected for the presence of NR associated with different types of epilepsy and/or with hand dystonia.