Outcome of ICSI using fresh and cryopreserved–thawed testicular spermatozoa in patients with non-mosaic Klinefelter's syndrome

BACKGROUND: Recently, intracytoplasmic sperm injection (ICSI) of testicular spermatozoa retrieved surgically from patients with non-mosaic Klinefelter's syndrome resulted in several deliveries. The aim of this study was to evaluate the outcome of ICSI using fresh and cryopreserved–thawed testicular spermatozoa in these patients. METHODS AND RESULTS: Following informed consent regarding the genetic risks of their potential offspring, mature testicular spermatozoa were found in five out of 12 (42%) patients who underwent testicular sperm extraction, and ICSI was performed while excess tissue was cryopreserved. The mean age of the patients was 28.7 ± 3.6 (range 23–36 years). Their baseline FSH was elevated (mean 38.3 ± 11.4; range 22–58 mIU/ml). All patients had small testicles of 2–4 ml in volume. The outcome of ICSI using fresh or cryopreserved–thawed testicular spermatozoa during five cycles in each group, was compared. No statistical significant difference was found in the two pronuclear fertilization rate (66 versus 58%), embryo cleavage rate (98 versus 90%) and embryo implantation rate (33.3 versus 21.4%) for fresh or cryopreserved sperm accordingly. The clinical outcome after using fresh testicular sperm included two singleton pregnancies (one delivered and one ongoing) and a triplet pregnancy resulting in a twin delivery (after reduction of an 47,XXY embryo). After using cryopreserved–thawed testicular spermatozoa, two pregnancies were obtained resulting in one delivery of twins and one early spontaneous abortion. CONCLUSIONS: Outcome of ICSI using cryopreserved–thawed testicular spermatozoa of patients with non-mosaic Klinefelter's syndrome is comparable with that following the use of fresh spermatozoa. The genetic implications for the future offspring should be explained to the patients.