Prospective assessment of Y-chromosome microdeletions and reproductive outcomes among infertile couples of Japanese and African origin

Abstract

BackgroundTo compare the frequency of Y-chromosome microdeletions in Japanese and African azoospermic and oligozoospermic men and describe embryo characteristics and reproductive outcome following in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI).MethodsOur study was performed prospectively at two centers, a private IVF clinic and a university hospital. Japanese and African (Tanzanian) men with nonobstructive azoospermia (NOA) and oligozoospermia (concentration < 5 × 106 /ml) were evaluated for Y-chromosome microdeletions (n = 162). Of the 47 men with NOA, 26 were Japanese and 21 were Africans. Of the 115 men with oligozoospermia, 87 were Japanese and 28 were Africans. Reproductive outcomes of patients with Y-chromosome microdeletions were then compared with those of 19 IVF+ICSI cycles performed on couples with Y-chromosome intact males/tubal factor infertility which served as a control group.ResultsSeven azoospermic and oligozoospermic patients had Y-chromosome deletions; the total number of deletions in the AZFc region was five. There was only one deletion in the AZFa region and one complete deletion involving all three regions (AZFa, b, and c) within AZF. In our study population, microdeletion frequency among Japanese men was 6.2% (95% CI, 4.25% – 14.45%), whereas no deletions were identified in the African group (95% CI, 0.0% – 7.27%). The difference between the two groups was not statistically significant, however. Embryos derived from ICSI utilizing sperm with Y-chromosome microdeletion showed reduced rates of fertilization, blastocyst development, implantation, and pregnancy compared to the Y-chromosome intact group, although these observed differences were not statistically significant.ConclusionThe observed frequency of Y-chromosome microdeletion was 6.2% among Japanese azoospermic and oligozoospermic males; no microdeletions were identified among our African study patients. In this population of couples undergoing IVF+ICSI, there was no statistically significant difference in embryo characteristics or pregnancy outcome between patients with Y-chromosome microdeletion and those with an intact Y-chromosome.

Comparative Study of AZF Deletions and TSPY Gene Variation in Czech and Indian Infertile Men

“…Calleja Macia et al (2003) who reported an incidence 13.9% of AZF deletions in azoospermics, also did not find any deletion in their oligospermic cases. Kihaile et al (2005) also did not find any AZF deletions among oligospermics. Many researchers have observed that frequencies of AZF deletions are lower among oligospermics as compared to azoospermics (Bor et al 2002;Kerr et al 2000).…”

“…The frequency of AZFa+b+c deletions is relatively low in all populations. Kihaile et al (2005) also observed only one such case among 47 azoospermics from Japan and Africa. El Awady et al (2004) and Loginova et al (2003) each reported one such case amongst infertile men studied by them.…”

“…Concurrent to these, OkutmanEmonts et al (2004) and Machatkova et al (2003) also did not find any AZFa deletion among their 71 Turkish and 198 Czech cases, respectively. Least frequencies of AZFa deletions among azoospermic men have been reported among Russians (Loginova et al 2003), Chinese (Yang et al 2003), North Americans (Hopps et al 2003), Indians (Thangaraj et al 2003) and Japanese (Kihaile et al 2005).…”

“…However, a wide variation of such microdeletions has been observed in different geographical regions. Kihaile et al (2005) have reported complete absence (0%) of AZF deletions in their sample of azoospermics from Africa, while frequencies of 6.7% in Brazil (Sao Pedro et al 2003), 7.1% in Japan (Carvallo et al 2003), and 10% in Romania (Raicu et al 2003) have been observed. A high frequency of 19.3% was reported from India by Rao et al (2004) and even a frequency of 55% has been reported (Foresta et al 1998).…”

“…Micro-deletions of AZF especially of AZFa, AZFb, and AZFc regions, within the MSY have been reported in infertile men. Widely different frequencies of such deletions, ranging from 0% to 55%, have been reported (Foresta et al 1998;Kihaile et al 2005). This large inter-laboratory variation in the frequency of AZF deletions is probably due to the type of patients selected for Y chromosome analysis (McElreavey and Krausz 1999).…”