Klinefelter's syndrome (karyotype 47,XXY) and schizophrenia-spectrum pathology

Klinefelter's syndrome, characterised by a 47,XXYchromosomal pattern, has largely been associated with physical abnormalities. Here, we report high levels of schizophrenia-spectrum pathology in 32 men with this syndrome in comparison with 26 healthy controls. This may have implications for treatment of Klinefelter's syndrome and suggests that the X chromosome may be involved in the aetiology of schizophrenia.