Schizophrenia is a later‐onset feature of PCDH 19 Girls Clustering Epilepsy

Summary Objective To investigate the occurrence of psychosis and serious behavioral problems in females with protocadherin 19 gene ( PCDH19 ) pathogenic variants. Methods We evaluated whether psychosis and serious behavioral problems had occurred in 60 females (age 2‐75 years) with PCDH 19 pathogenic variants belonging to 35 families. Patients were identified from epilepsy genetics databases in Australia, New Zealand, the United States, and Canada. Neurologic and psychiatric disorders were diagnosed using standard methods. Results Eight of 60 females (13%) from 7 families developed a psychotic disorder: schizophrenia (6), schizoaffective disorder (1), or an unspecified psychotic disorder (1). Median age at onset of psychotic symptoms was 21 years (range 11‐28 years). In our cohort of 39 females aged 11 years or older, 8 (21%) developed a psychotic disorder. Seven had ongoing seizures at onset of psychosis, with 2 continuing to have seizures when psychosis recurred. Psychotic disorders occurred in the setting of mild (4), moderate (2), or severe (1) intellectual disability, or normal intellect (1). Preexisting behavioral problems occurred in 4 patients, and autism spectrum disorder in 3. Two additional females (3%) had psychotic features with other conditions: an adolescent had recurrent episodes of postictal psychosis, and a 75‐year‐old woman had major depression with psychotic features. A further 3 adolescents (5%) with moderate to severe intellectual disability had onset of severe behavioral disturbance, or significant worsening. Significance We identify that psychotic disorders, including schizophrenia, are a later‐onset manifestation of PCDH 19 Girls Clustering Epilepsy. Affected girls and women should be carefully monitored for later‐onset psychiatric disorders.