Epilepsy-intellectual disability in females

Epilepsy-intellectual disability in females is a rare form of epilepsy that predominantly affects females and is marked by clusters of brief seizures that begin in infancy or early childhood, typically between four and sixty months of age, often accompanied by fearful screaming and usually lasting only one to five minutes each. The condition arises from mutations in the PCDH19 gene, carried on the X chromosome, which normally directs production of the protocadherin 19 protein involved in communication between developing brain cells; a mutation can leave this protein malformed, reduced in function, or entirely absent, disrupting normal neural development. Cognitive impairment accompanies the seizures in an estimated sixty to seventy-five percent of affected females, ranging from mild to severe, though some develop normally; associated behavioral features can include autism spectrum symptoms, attention-deficit hyperactivity disorder, and anxiety. The disorder follows an unusual inheritance pattern for an X-linked condition: affected men have a one hundred percent chance of passing the mutation to a daughter and no chance of passing it to a son, and roughly ninety percent of females who carry the mutation show symptoms, while men who carry it typically remain asymptomatic, a reversal of the usual pattern in which X-linked disorders affect males more severely than the female carriers.