[Neurological aspects of two patients with non-mosaic and mosaic polysomy of the X and Y chromosomes].

Clinical features were compared of a patient with the 48,XXYY karyotype and a case of 47,XXY/48,XXYY mosaicism. In the former patient tremor of the upper extremities of unclear aetiology was present. In both cases epilepsy was suspected. Similarly as in other cases of 48,XXYY karyotype the first patient had skeletal anomalies, abnormalities of dermatoglyphics and personality changes. These features are rarely found in Klinefelter syndrome. The differences in relation to the syndrome were less evident in the case of mosaicism 47,XXY/48,XXYY.