Study Of The Relationship Between The Partial Deletions In The AZFc Region And Male Infertility

There were a lot of complex causes which lead to male infertility. The major form of male infertility was the spermatogenesis impairment. Currently, there were many factors which associated with male infertility, such as, hypogonadism, varicocele, urogenital infection, vas deferens obstruction, cryptorchidism, acquired orchitisetc, etc. The spermatogenesis dysfunction caused by genetic defect, including chromosomal abnormality and gene mutation, was in about 30% of male infertility. The chief pathogeny is chromosomal abnormality which accounts for 2-5%. Thus, there are still some other causes which associated with genetic factors leading to male infertility remain to be deciphered. In recent years, studies have shown that male infertility was related to the chromosomal abnormality, in particular the absence of spermatogenic gene on Y chromosome long arm.This study analyzed a population of 494 subjects (including 177 azoospermia, 177 serious oligozoospermia, 140 oligozoospermia and 236 fertile men with normal spermatogenesis), to investigate the correlation of male infertility with abnormality of chromosomal construction and quantity and with the microdeletion of azoospermia factor (AZF) gene on the Y chromosome. As well as the reletionship between the partial deletions in the AZFc region of Y chromosome and male infertility.Multiplex-PCR technique was used to detect microdeletions of AZF gene in 494 infertile men and 236 fertile controls with fifteen sequence-tagged sites (STSs). Chromosome karyotype analyses were performed in the 494 patients. Multiplex-PCR technology was performed to screen the partial deletions in the AZFc region in infertile men with no AZF mircodeletions and 236 fertile men with normal spermatogenesis. For samples with gr/gr, b2/b3 recombinogenic deletion,we applied PCR-RFLP method to identify which DAZ gene copies doublet deletion was involved. The results were shown as follows:1. Totally, 30 cases with chromosomal construction and quantity abnormalities were detected in 494 infertile men with spermatogenesis impairment, the total rate of chromosomal abnormality was 6.07% (30/494), including 11.86% (21/177), 1.69% (3/177), 4.29% (6/140) in azoospermia, severe oligozoospermia and oligozoospermia, respectively.2. There were no microdeletions in 236 fertile controls but 41 microdeletions in 494 infertile men with spermatogenesis impairment. The total rate of microdeletion was 8.30% (41/494), including 10.73% (19/177), 9.60% (17 /177) and 3.57% (5/140) in azoospermia, severe oligozoospermia and oligozoospermia, respectively. The rates of AZF microdeletion in azoospermia and severe oligozoospermia were significant higher than that of the oligozoospermia.3. The gr/gr and b2/b3 were two types of common deletions detected, there were significant differences in the b2/b3 deletion between patients with oligozoospermia and serious oligozoospermia and controls (both P<0.05). However, there was no difference for the gr/gr deletion between patients and controls.There was a high frequency of chromosomal construction and quantity abnormality and microdeletion of AZF gene in patients with azoospermia, severe oligospermia and oligospermia, which suggested that chromosomal abnormality and microdeletion of AZF gene might be the important genetic causes of male infertility; There are several types of partial deletion in the AZFc region on Y chromosome, gr/gr-DAZ1/DAZ2 and gr/gr-DAZ3/DAZ4 deletion might slightly affect male spermatogenesis and exist as a kind of genomic polymorphism. b2/b3-DAZ3/DAZ4 deletion is the high risk factor to spermatogenic failure of male infertility.