Analysis of meiosis in intratesticular germ. cells from subjects affected by classic Klinefelter's syndrome

Azoospermic subjects affected by Klinefelter's syndrome may occasionally sh ow the presence of intratesticular residual foci of spermatogenesis, and th e retrieval of mature spermatozoa from the testis may permit fertility and paternity by means of intracytoplasmic sperm injection. Previous studies have demonstrated that these subjects show the presence of an increased incidence of hyperaploid spermatozoa. Here we analyzed, by fl uorescence in situ hybridization using specific probes for chromosomes 8, X , and Y, the spermatogenic process and the meiotic progression of 47,XXY ge rm cells retrieved by fine needle aspiration of the testis in ten azoosperm ic patients affected by classic Klinefelter's syndrome. All patients had lo wer testicular volume, higher gonadotropins, and lower testosterone plasma levels compared with control subjects. Cytological analysis of the testicul ar cells retrieved by fine needle aspiration showed the presence of Sertoli cells only in eight subjects, while germ cells were observed in two patien ts. In each patient Sertoli cells showed a 47,XXY karyotype, and the same c hromosome pattern was observed in spermatogonia and primary spermatocytes o f patients presenting a residual spermatogenesis. Secondary spermatocytes, spermatids, and mature spermatozoa showed different sex chromosome patterns , reflecting their origin from 47,XXY spermatogonia. In conclusion, this study demonstrated that, in subjects affected by Klinef elter's syndrome, residual germ cells may be present in the testis and that 47,XXY spermatogonia are able to undergo and complete the spermatogenic pr ocess leading to mature spermatozoa. These data further suggest the need to evaluate the sex chromosome status of sperm from patients affected by Klin efelter's syndrome undergoing assisted reproductive techniques.