Hormonal studies in a male with a 47,XXX chromosome constitution: comparison with the hormonal pattern of a 46,XX male and patients with Klinefelter's syndrome.

Chromosome analysis in peripheral blood lymphocytes and skin fibroblasts of a 18 year old chromatin-positive man showed a 47,XXX karyotype. The following hormonal studies were performed: 1) FSH and LH response to GnRH; 2) hypothalamic-pituitary responsiveness to short-term testosterone administration; 3) plasma levels of testosterone, dihydrotestosterone, 17-hydroxyprogesterone, estradiol before and after hCG stimulation. Results were compared with similar studies performed in a 46,XX male and in a group of patients with Klinefelter's syndrome. Our data support the hypothesis that this rare cytogenetical disorder can be considered, from the endocrine point of view, as a variant of the Klinefelter's syndrome.