Preimplantation Genetic Testing for Aneuploidy (PGT-A) in Couples With Non-obstructive Azoospermia (NOA)

Overview

Objective: To examine the rate of embryo aneuploidy in patients with non-obstructive azoospermia (NOA) who utilize in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) and compare live birth rates with the utilization of preimplantation genetic testing for aneuploidy (PGT-A) vs non PGT-A.

Preimplantation genetic testing for aneuploidy (PGT-A) facilitates selection of euploid embryos for transfer and may improve outcomes in select couples when the female partner is 35 or older. While embryonic aneuploidy is known to be associated with maternal risk factors such as advanced age, the male factors contributing to aneuploidy are not as clear. Severe male factor infertility is associated with various genetic causes, including karyotypic abnormalities. One retrospective analysis of 668 infertile patients diagnosed with various nonobstructive spermatogenic defects using high resolution Giemsa banding chromosome analysis and/or fluorescence in situ hybridization revealed constitutional chromosomal abnormalities in 55 (8.2%) patients. The observed incidence was almost 20-fold greater than what is reported in healthy fertile men (0.37%). This study correlated cytogenetic aberrations with male reproductive phenotypes and noted that sex chromosome aneuploidy was the most common finding in azoospermia (AS) cases, accounting for about 9%, with Klinefelter syndrome (47, XXY karyotype and variants) accounting for 4% of all infertile males. Notably, the 47, XXY karyotype was detected at a considerably higher rate in men with AS vs oligospermia (OS) (27 of 668 or 9.1% vs 3 of 365 or 0.8%). Little is known about the impact of constitutional aneuploidy on embryonic aneuploidy rates after fertilization with surgically extracted sperm. Another study examined the impact of severe male factor infertility in 326 cycles on aneuploidy in embryos and found significant increases in embryo aneuploidy and higher mosaicism rates in cases using testicular sperm from patients with severe male factor infertility as compared to non-male factor controls. This study found that the statistically significant affected chromosomes were 2, 10, 11, 17, 21 and sex chromosomes. While sperm chromosomal aneuploidy are consistently higher in severe male factor infertility, the impact on IVF outcomes and potential benefits of PGT-A are unclear. Additionally, data on differences in aneuploidy rates between OA and NOA are mixed. Further research is warranted to help facilitate appropriate counseling of affected couples and better understand the role of PGT-A in severe male-factor infertility treatment. We will conduct a retrospective chart review to examine the rates of aneuploidy in embryos resulting from ICSI with surgically extracted sperm in patients with NOA and OA and characterize the chromosomes commonly affected in identified aneuploid embryos.

Conditions

Eligibility

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Outcomes