Neuropsychiatric Phenotype and Treatment Challenges in 47,XYY Syndrome: A Narrative Review with a Case Series of Adolescents

47,XYY syndrome is a relatively common sex chromosome aneuploidy that remains largely underdiagnosed. While its somatic phenotype is often mild, growing evidence indicates a substantial burden of neurodevelopmental and psychiatric morbidity. However, the characterization of the neuropsychiatric phenotype across development, particularly during adolescence, and the associated treatment challenges remain incomplete.

To provide a comprehensive narrative review of the neuropsychiatric phenotype of 47,XYY syndrome and to illustrate clinical complexity and treatment response through a case series of adolescents.

A narrative review of the literature was conducted focusing on genetics, neurodevelopmental and psychiatric features, neuroimaging and neurophysiology findings, clinical course, and management strategies in 47,XYY syndrome. This review is complemented by a case series of adolescents with confirmed 47,XYY karyotype, evaluated for developmental history, psychiatric comorbidity and response to pharmacological and non-pharmacological interventions.

The literature consistently describes increased risks of language impairment, executive dysfunction, ADHD, autism spectrum traits, and emotional and behavioral dysregulation in males with 47,XYY syndrome. Psychiatric vulnerability appears to increase during adolescence and adulthood, with elevated rates of mood, psychotic, and substance use disorders. The presented cases illustrate a convergent clinical trajectory marked by early developmental delays, progressive behavioral dysregulation in adolescence and limited or inconsistent response to multiple classes of psychotropic medications, suggesting a pattern of pharmacoresistance in a subset of patients.

47,XYY syndrome is associated with a distinct and heterogeneous neuropsychiatric phenotype that extends beyond early neurodevelopmental disorders. Early diagnosis alone may be insufficient to prevent severe psychiatric outcomes, highlighting the need for long-term monitoring and integrated, multidisciplinary management. Further research is required to identify early predictors of high-risk trajectories and to optimize treatment strategies for this population.