PCDH19-related epilepsy is associated with a broad neurodevelopmental spectrum.

Our series represents a robust cohort with carefully curated PCDH19 variants. We observed seizures as a core feature with a range of seizure types and severity. Whereas the majority of individuals had ID, we highlight the possibility of average intellect in the setting of PCDH19-related epilepsy. We also note the high prevalence and severity of neurobehavioral phenotypes associated with likely pathogenic variants in PCDH19. Sleep dysregulation was also a major area of concern. Our data emphasize the importance of appropriate referrals for formal neuropsychological evaluations as well as the need for formal prospective studies to characterize the PCDH19-related neurodevelopmental syndrome in children and their genotype-positive parents.