Snapshot A 32-year-old prisoner in the county detention center has been denied parole due to his repeated disregard of civil obediance and overtly aggressive behavior. He is very tall and has severe acne. Upon return, he agrees to participate in a genetic study looking at markers for aggressive behavior in humans. Introduction Genetic abnormality where males are born with two copies of the Y chromosome (47XYY) Most patients appear phenotypically normal tendency to be taller than most males may have severe acne Genotype has been found in increased frequency among males of correctional facilities Hypothesized to impart more aggressive and potentially violent behavior in affected males Presentation Symptoms may display antisocial behavior Physical exam most individuals are phenotypically normal common features include increased height severe acne antisocial behavior Evaluation Given normal phenotype in most cases, usually diagnosed incidentally Genotyping identifies extra Y chromosome (47XYY) Differential Differential diagnosis may be limited to other genetic disorders sharing tall height as characteristic, though differ markedly in other aspects, including Klinefelter's syndrome and Marfan syndrome Treatment Medical management behavioral therapy and counseling may be indicated in individuals demonstrating antisocial behavior Prognosis, Prevention, and Complications Prognosis very good to excellent most cases live very happy and fulfilled normal lives Prevention no preventive measures are available at this time Complications antisocial behavior may result in remediation at correctional facility/imprisonment