Deletion or underexpression of the Y-chromosome genes CDY2 and HSFY is associated with maturation arrest in American men with nonobstructive azoospermia

Maturation arrest （MA） refers to failure of germ cell development leading to clinical nonobstructive azoospermia. Although the azoospermic factor （AZF） region of the human Y chromosome is clearly implicated in some cases, thus far very little is known about which individual Y-chromosome genes are important for complete male germ cell development. We sought to identify single genes on the Y chromosome that may be implicated in the pathogenesis of nonobstructive azoospermia associated with MA in the American population. Genotype-phenotype analysis of 132 men with Y-chromosome microdeletions was performed. Protein-coding genes associated with MA were identified by visual analysis of a genotype-phenotype map. Genes associated with MA were selected as those genes within a segment of the Y chromosome that, when completely or partially deleted, were always associated with MA and absence of retrievable testicular sperm. Expression of each identified gene transcript was then measured with quantitative RT-PCR in testicular tissue from separate cohorts of patients with idiopathic MA and obstructive azoospermia. Ten candidate genes for association with MA were identified within an 8.4-Mb segment of the Y chromosome overlapping the AZFb region. CDY2and HSFYwere the only identified genes for which differences in expression were observed between the MA and obstructive azoospermia cohorts. Men with obstructive azoospermia had 12-fold higher relative expression of CDY2transcript （1.33__.0.40 vs. 0.11＋_0.04; P=O.O003） and 16-fold higher expression of HSFYtranscript （0.78__.0.32 vs. 0.05_0.02; P=O.O005） compared to men with MA. CDY2 and HSFYwere also underexpressed in patients with Sertoli cell only syndrome. These data indicate that CDY2and HSFYare located within a segment of the Y chromosome that is important for sperm maturation, and are underexpressed in testicular tissue derived from men with MA. These observations suggest that impairments in CDY2 or HSFYexpression could be implicated in the pathogenesis of MA.

Uniform deletion junctions of complete azoospermia factor region c deletion in infertile men in Taiwan

Aim： To determine the deletion junctions of infertile men in Taiwan with azoospermia factor region c （AZFc） deletions and to evaluate the genotype/phenotype correlation. Methods： Genomic DNAs from 460 infertile men were examined. Bacterial artificial chromosome clones were used to verify the accuracy of polymerase chain reaction. Deletion junctions of the AZFc region were determined by analysis of sequence-tagged sites and gene-specific markers. Results： Complete AZFc deletions, including BPY2, CDY1 and DAZ genes, were identified in 24 men. The proximal breakpoints were clustered between sY1197 and sY1192, and the distal breakpoints were clustered between sY1054 and sYl125 in all but one of the 24 men. The testicular phenotypes of men with complete AZFc deletion varied from oligozoospermia, to hypospematogenesis, to maturation arrest. Conclusion： We identified a group of infertile men with uniform deletion junctions of AZFc in the Taiwan population. Despite this homogeneous genetic defect in the AZFc region, no clear genotypedphenotype correlation could be demonstrated. （Asian JAndrol 2006 Mar; 8： 205-211）