Towards the molecular localisation of the AZF locus: mapping of microdeletions in azoospermic men within 14 subintervals of interval 6 of the human Y chromosome

Abstract

We have used a series of 30 DNA probes previously mapped to the long arm of the human Y chromosome, to screen a panel of 21 patients with structural abnormalities in Yq, by genomic blot hybridisation. The results have allowed us to construct a detailed map of interval 6 of the Y chromosome, in which 28 of the probes could be assigned to 14 sub-intervals within interval 6. Some probes detect two or more loci within this region, each of which has been localised. The same set of probes has been used to screen a panel of 19 chromosomally normal azoospermic men, two of whom have been found to carry microdeletions within this region. With the completion of this map we have been able accurately to localise these microdeletions within interval 6 and show that they do not overlap. We believe these microdeletions may disrupt the azoospermia factor (AZF) involved in spermatogenesis, and which is known to lie in this region. These results are an important step towards the localisation of the AZF locus.

Y chromosome AZFc microdeletion may not affect the outcomes of ICSI for infertile males with fresh ejaculated sperm

“…The variation in the reported rate is likely caused by the difference in study design and patient cohort selection [4]. The initial cytogenetic observation of an azoospermia factor (AZF) present on Yq was made in 1976, which enabled molecular analysis of Yq microdeletion in infertile men for the first time [5][6][7][8]. Subsequently, the long arm of the Y chromosome was shown to contain three AZF regions, namely AZFa, AZFb, and AZFc, from proximal to distal Yq [8].…”

Prevalence of Y chromosome deletions in a Brazilian population of nonobstructive azoospermic and severely oligozoospermic men

“…This gene or gene cluster was defined as azoospermia factor (AZF). Subsequent PCRbased screening studies used to amplify sequence-tagged sites (STS) spanning the Y chromosome (2,3) facilitated the detection of small interstitial deletions (i.e., microdeletions) of Yq11 not only in azoospermic (4)(5)(6), but also in severely oligozoospermic men (7,8). Since these deletions were variable in both extent and location, the AZF region was divided into three nonoverlapping subregions (AZFa, AZFb and AZFc) located from the S.L.…”

Multiplex Sequence-Tagged Site PCR for Efficient Screening of Microdeletions in Y Chromosome in Infertile Males with Azoospermia or Severe Oligozoospermia

“…Tiepolo and Zu ardi ®rst demonstrated cytogenetically that the detectable genes of spermatogenesi s exist on the long arm of the Y chromosome (Yq) and termed this region the azoospermia factor (AZF) [20]. The existence of AZF on interval 6 on Yq was proved by means of molecular±biological strategy with genomic DNA [5,9]. In recent years, there have been numerous reports that Y-chromosome microdeletions correlate with male infertility.…”