Effects of a Partial Deletion of the Y Chromosome Azoospermia Factor (gr/gr Deletion) on Intracytoplasmic Sperm Injection Outcomes

Purpose: The azoospermia factor (AZF), which is located on the long arm of the Y-chromosome, is involved in spermatogenesis. The frequency of gr/gr deletion, a partial deletion in the AZFc region, has been reported to show ethnic variations; the gr/gr deletion shows a high frequency in Asian men with infertility. Generally, gr/gr deletions do not exert an strong influence on fertility for Asians; however, whether intracytoplasmic sperm injection outcomes also remain unaffected by these deletions remains unclear. Thus, the present study aimed to examine AZF deletions, with a particular focus on gr/gr deletion, in East Asian subjects, to identify their effects on intracytoplasmic sperm injection outcomes.Methods: A total of 204 East Asian patients with a normal male karyotype who underwent AZF testing between July 2014 and August 2018 were selected for this retrospective study.Results: Of the 204 East Asian subjects, 200 were Japanese. Furthermore, 83 exhibited AZF deletions, of whom 65 exhibited a gr/gr deletion and 118 exhibited no AZF deletion. A total of 37 patients in the gr/gr-deletion group (56.9%) and 77 in the group without AZF deletion (65.3%) were subjected to testicular sperm extraction (TESE) including microdissection-TESE (MD-TESE). Sperm retrieval was performed for 18 patients (48.6%) in the gr/gr-deletion group and in 36 patients (46.8%) of the group without AZF deletion. The fertilization rate, as ascertained using the TESE-derived sperms, was 54.8% (85/155) for the gr/gr-deletion group and 89.1% (554/622) for the group without AZF deletion (p < 0.01).Conclusions: The fertilization rate was significantly lower for the sperm samples from the gr/gr-deletion group than for those from the control group. The AZF gr/gr deletion did not affect spermatogenesis, but there were concerns that it may affect the fertilizing capacity of testicular sperms in East Asians.Funding Information: This study was not supported by any funding agencies. Declaration of Interests: The authors declare that they have no conflict of interest. Ethics Approval Statement: All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964 and its later amendments. Informed consent for the AZF test was obtained from all participants included. The participants were given the opportunity to decline using their test results for the present study. This report was approved by the Ethics Committee of Faculty of Medicine, Toho University (No. A18024).