Cognitive development in females with PCDH19 gene-related epilepsy.

Mutations in the PCDH19 gene are now recognized to cause epilepsy in females and are claiming increasing interest in the scientific world. Clinical features and seizure semiology have been described as heterogeneous. Intellectual disability might be present, ranging from mild to severe; behavioral and psychiatric problems are a common feature of the disorder, including aggressiveness, depressed mood, and psychotic traits. The purpose of our study was to describe the cognitive development in 11 girls with a de novo mutation in PCDH19 and early-onset epilepsy. Six patients had average mental development or mild intellectual disability regardless of persistence of seizures in clusters. Five patients presented moderate or severe intellectual disability and autistic features. In younger patients, we found that despite an average developmental quotient, they all presented a delay of expressive language acquisition and lower scores at follow-up testing completed at older ages, underlining that subtle dysfunctions might be present. Larger cohort and long-term follow-up might be useful in defining cognitive features and in improving the care of patients with PCDH19.