Profiling the male germline genome to unravel its reproductive potential

Objective: To identify specific germline mutations related to sperm reproductive competence, in couples with unexplained infertility.Design: In this retrospective study, couples were divided according to whether they had successful intracytoplasmic sperm injection outcomes (fertile) or not (infertile). Ancillary sperm function tests were performed on ejaculates, and whole exome sequencing was per-formed on spermatozoal DNA. Sperm aneuploidy and gene mutation profiles were compared between the 2 cohorts as well as according to the specific reasons for reproductive failure.Setting: Center for reproductive medicine at a major academic medical center.Patient(s): Thirty-one couples with negative infertility workups and normal semen parameters.Intervention(s): Couples with mutations on fertilization-or embryo development-related genes were subsequently treated by assisted gamete treatment or microfluidics, respectively.Main Outcome Measure(s): Intracytoplasmic sperm injection cycle outcomes including fertilization, clinical pregnancy, and delivery rates.Result(s): Sperm aneuploidy was lower in the fertile group (4.0% vs. 8.4%). Spermatozoa from both cohorts displayed mutations asso-ciated with sperm-egg fusion (ADAM3A) and acrosomal development (SPACA1), regardless of reproductive outcome. The infertile cohort was then categorized according to the reasons for reproductive failure: absent fertilization, poor early embryo development, implantation failure, or pregnancy loss.Spermatozoa from the fertilization failure subgroup (n = 4) had negligible PLCzpresence (10% + 9%) and gene mutations (PLCZ1, PIWIL1, ADAM15) indicating a sperm-related oocyte-activating deficiency. These couples were successfully treated by assisted gamete treatment in their subsequent cycles.Spermatozoa from the poor early embryo development subgroup (n = 5) had abnormal centrosomes (45.9% + 5%), and displayed mutations impacting centrosome integrity (HAUS1) and spindle/microtubular stabilization (KIF4A, XRN1). Microfluidic sperm pro-cessing subsequently yielded a term pregnancy.Spermatozoa from the implantation failure subgroup (n = 7) also had abnormal centrosomes (53.1% + 13%) and carried mutations affecting embryonic implantation (IL9R) and microtubule and centrosomal integrity (MAP1S, SUPT5H, PLK4), whereas those from the pregnancy loss subgroup (n = 5) displayed mutations on genes involved in trophoblast development (NLRP7), cell cycle regulation (MARK4, TRIP13, DAB2IP, KIF1C), and recurrent miscarriage (TP53).Conclusion(s): By assessing the sperm genome, we identified specific germline mutations related to various reproductive processes. This information may clarify elusive factors underlying reproductive competence and enhance treatment for couples with unexplained infertility. (Fertil Steril (R) 2023;119:196-206. (c) 2022 by American Society for Reproductive Medicine.)El resumen esta disponible en Espanol al final del articulo.