The presence of an extra X-chromosome, also known as Klinefelter's Syndrome, occurs in approximately 1 in 500 live male births. Epidemiological studies have reported an increased vulnerability to psychiatric disturbances in this group of patients and suggest that the X chromosome may be involved in the aetiology.

Comprehensive review of the scientific literature (Medline, Ovid) on Psychiatric pathology in Klinefelter's Syndrome published over the last 20 years.

This is a case report of a 27 year-old-male with Klinefelter's Syndrome confirmed by karyotyping (XXY), suffering from different neuropsychiatric disorders, such as mental retardation, dyslexia, ADHD and social dysfunctioning. Since the age of 16 he has required multiple psychiatric hospitalizations due to his impulse control difficulties and exaggerated mood swings.This case raises the question of whether Klinefelter's syndrome patients are predisposed to psychiatric pathology (including Schizophrenia, Bipolar Disorder, Anorexia Nervosa or social-emotional processing) at a genetic level.

Reviews of the neuropsychiatric problems associated with Klinefelter's Syndrome confirm an association between disorders in this area and the chromosomal abnormality. Further studies are needed to identify involvement of X-linked epigenetic influence and susceptibility to several psychiatric diseases.