Definition:

PCDH19-related epilepsy syndrome is a disorder characterized by the recurrence of seizures during infancy, which is often combined with intellectual disability or autistic features manifested exclusively in females. This disorder, first reported as epilepsy and mental retardation limited to females (EMFR) and recently renamed early infantile epileptic encephalopathy 9 (EIEE9). It was transmitted via asymptomatic males, suggesting an unusual X-linked inheritance with selective involvement of females. Mutations in the X-chromosome-encoded protocadherin 19 (PCDH19) cause this disorder, and are confirmatory for the diagnosis.