Chromosomal aneuploidy is recognized as a factor that contributes to unsuccessful embryo implantation and spontaneous abortion. It provides an explanation for the relatively low success rate of in vitro fertilization (IVF) treatments. Preimplantation genetic screening is widely used to identify chromosomally normal (euploid) embryos and select them for intrauterine transfer in order to improve the clinical outcome of IVF.¹

Background: Preimplantation genetic testing (PGT) is widely used today in in-vitro fertilization (IVF) centers over the world for selecting euploid embryos for transfer and to improve clinical outcomes in terms of embryo implantation, clinical pregnancy, and live birth rates. Methods: We report the current knowledge concerning these procedures and the results from different clinical indications in which PGT is commonly applied. Results: This paper illustrates different molecular techniques used for this purpose and the clinical significance of the different oocyte and embryo stage (polar bodies, cleavage embryo, and blastocyst) at which it is possible to perform sampling biopsies for PGT. Finally, genetic origin and clinical significance of embryo mosaicism are illustrated. Conclusions: The preimplantation genetic testing is a valid technique to evaluated embryo euploidy and mosaicism before transfer.

The aim of this study is to determine if the use of preimplantation genetic screening (PGS) by array comparative genomic hybridization (array CGH) and transfer of a single euploid blastocyst in patients with repeated implantation failure (RIF) can improve clinical results. Three patient groups are compared: 43 couples with RIF for whom embryos were selected by array CGH (group RIF-PGS), 33 couples with the same history for whom array CGH was not performed (group RIF NO PGS), and 45 good prognosis infertile couples with array CGH selected embryos (group NO RIF PGS). A single euploid blastocyst was transferred in groups RIF-PGS and NO RIF PGS. Array CGH was not performed in group RIF NO PGS in which 1-2 blastocysts were transferred. One monoembryonic sac with heartbeat was found in 28 patients of group RIF PGS and 31 patients of group NO RIF PGS showing similar clinical pregnancy and implantation rates (68.3% and 70.5%, resp.). In contrast, an embryonic sac with heartbeat was only detected in 7 (21.2%) patients of group RIF NO PGS. In conclusion, PGS by array CGH with single euploid blastocyst transfer appears to be a successful strategy for patients with multiple failed IVF attempts.

Does the health status of infants fathered by nonmosaic Klinefelter syndrome (KS) patients whose partners underwent ICSI with sperm obtained from testicular dissection reveal any genetic risk for the offspring?. KS patients undergoing testicular sperm extraction (TESE) are capable of conceiving healthy children. Paternity has been successfully achieved in nonmosaic KS patients (47,XXY karyotype) by ICSI using either ejaculated or testicular spermatozoa. A crucial concern is the potential transmission of genetic abnormalities to the offspring. Some studies reported that 47,XXY spermatogonia are capable of completing spermatogenesis leading to the production of mature spermatozoa with increased aneuploidies. Other authors showed that where focal spermatogenesis is present in nonmosaic KS males, it originates from euploid germ cells and, therefore, produces normal mature gametes. In support of this finding, at present, the great majority of children born from nonmosaic KS patients are chromosomally normal. From April 2004 to June 2010, 38 azoospermic patients with nonmosaic KS were examined for the presence of testicular spermatozoa. Spermatozoa were retrieved from 15 patients and 26 ICSI cycles were done (16 with cryopreserved sperm). There were 15 pregnancies leading to the birth of 16 babies who were karyotyped at amniocentesis and after birth. Participants were recruited from couples attending the European Hospital, Rome, and Clinica MAR&Gen, Granada, for infertility treatment. Both the European Hospital and Clinica MAR&Gen are private clinics. Testicular tissue was extracted with TESE or micro-TESE. After retrieval, fresh sperm was used for ICSI or it was cryopreserved for future use. Spermatozoa were retrieved from 15 patients (14 TESE and 1 micro-TESE) out of 38 (39.5%). A total of 26 ICSI cycles were performed: 10 with fresh and 16 with cryopreserved-thawed sperm. Mean ages (y) of patients with positive and negative sperm retrieval were, respectively, 34.8 ± 1.72 and 35.6 ± 4.08 (NS, nonsignificant). Comparing ICSI cycles performed with fresh sperm (n = 10) to those performed with frozen–thawed sperm (n = 16): Fertilization rates per injected oocyte were 53.0% (44 of 83) and 47.8% (32 of 67), respectively (NS). The cleavage rate per injected oocyte was 90.6% (29 of 32) versus 68.2% (30 of 44); P = 0.026. Clinical outcomes were not significantly different between the fresh and the frozen–thawed sperm group: clinical pregnancy rates were 7 of 10 (70.0%) and 8 of 16 (50.0%); implanted embryos (per transferred embryo) were 8 of 23 (34.8%) and 8 of 29 (27.6%); delivery rates were 6 of 10 (60.0%) and 5 of 16 (31.3%). Sixteen babies were born, all of them are healthy with a normal karyotype, eight from the fresh sperm group and eight from the frozen–thawed sperm group. The small numbers available for study mean that only common problems can be excluded. This study provides further reassurance that KS men can father healthy children and that pre-implantation genetic diagnosis on embryos conceived with their sperm is not strongly indicated. However, until conclusive information is available, such couples should be offered extensive genetic counseling. No external funding was obtained for the present study. None of the authors has any conflict of interest to declare. Not applicable.

To provide indicators for the likelihood of sperm retrieval in patients undergoing testicular sperm extraction is a major issue in the management of male infertility by TESE. The aim of our study was to determine the impact of different parameters, including testicular histopathology, on sperm retrieval in case of reoperation in patients undergoing testicular sperm extraction. We retrospectively analyzed 486 patients who underwent sperm extraction for intracytoplasmic sperm injection and testicular biopsy. Histology was classified into: normal spermatogenesis; hypospermatogenesis (reduction in the number of normal spermatogenetic cells); maturation arrest (absence of the later stages of spermatogenesis); and Sertoli cell only (absence of germ cells). Semen analysis and serum FSH, LH and testosterone were measured. Four hundred thirty patients had non obstructive azoospermia, 53 severe oligozoospermia and 3 necrozoospermia. There were 307 (63%) successful sperm retrieval. Higher testicular volume, lower levels of FSH, and better histological features were predictive for sperm retrieval. The same parameters and younger age were predictive factors for shorter time for sperm recovery. After multivariable analysis, younger age, better semen parameters, better histological features and lower values of FSH remained predictive for shorter time for sperm retrieval while better semen and histology remained predictive factors for successful sperm retrieval. The predictive capacity of a score obtained by summing the points assigned for selected predictors (1 point for Sertoli cell only, 0.33 points for azoospermia, 0.004 points for each FSH mIU/ml) gave an area under the ROC curve of 0.843. This model can help the practitioner with counseling infertile men by reliably predicting the chance of obtaining spermatozoa with testicular sperm extraction when a repeat attempt is planned.