RESUMO
OBJECTIVE: To discuss the relationship between XYY chromosome abnormality, psychiatric disorders and epilepsy. METHOD: Single case report. RESULTS: A 34-year-old man with 47, XYY karyotype and normal intelligence was followed-up at a neuropsychiatric clinic for over 30 years. He was first seen at age 3 years with a history of delayed motor and language development and an immunodeficiency syndrome. At age 8 years he developed refractory focal epilepsy, and in late adolescence he started to exhibit increasingly prominent obsessive thoughts, paranoid ideation, and aggressive sexual fantasies and behaviour. CONCLUSIONS: When interpreted within the context of previous literature reports, this case suggests a pathophysiological link between XYY chromosome abnormality, characteristic psychiatric symptoms and epilepsy disorder.