title: Additional genomic duplications in AZFc underlie the b2/b3 deletion-associated risk of spermatogenic impairment in Han Chinese population.
abstract: The azoospermia factor c (AZFc) region on the Y chromosome is a genetically dynamic locus in the human genome. Numerous genomic rearrangements, including deletion, duplication and inversion, have been identified in AZFc. The complete deletion of AZFc can cause spermatogenic impairment. However, the roles of partial AZFc deletions (e.g. b2/b3 deletion) in spermatogenesis are controversial and variable among human populations. Secondary duplication has been hypothesized to be a compensatory factor for partial AZFc deletions. To further study genomic duplications in AZFc as a potential genetic modifier underlying the phenotypic variations of partial AZFc deletions in spermatogenesis, we conducted comprehensive molecular analyses in 711 idiopathic infertile men and 390 healthy controls. Unexpectedly, we found that additional AZFc duplications accompanying the b2/b3 deletion, instead of the b2/b3 deletion alone, led to the b2/b3 deletion-associated risk of spermatogenic impairment previously reported in Han Chinese population. In addition, partial AZFc duplication also rendered a risk factor in the non-deletion patients. DAZ is a multi-copy AZFc gene (DAZ1-DAZ4) implicated in spermatogenesis. Genetic variations do exist between DAZ copies. Intriguingly, we found that the DAZ1/2 cluster was the main duplicated copies in the partial AZFc duplications associated with spermatogenic impairment, suggesting a potential different role of spermatogenesis between DAZ copies. Our findings demonstrated that additional AZFc duplications did not compensate but convey the susceptibility of the b2/b3 deletion to spermatogenic impairment in the tested population. Notably, genomic duplications and deletions in AZFc deserve comprehensive investigations to uncover spermatogenic roles of the AZFc region.
authors.affiliation: Key Laboratory of Reproductive Medicine, School of Public Health, Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Chuncheng
authors.initials: C
authors.lastname: Lu
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: Miaofei
authors.initials: M
authors.lastname: Xu
authors.forename: Guizhen
authors.initials: G
authors.lastname: Du
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Yu
authors.initials: Y
authors.lastname: An
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Qin
authors.forename: Guixiang
authors.initials: G
authors.lastname: Ji
authors.forename: Xiumei
authors.initials: X
authors.lastname: Han
authors.forename: Aihua
authors.initials: A
authors.lastname: Gu
authors.forename: Yankai
authors.initials: Y
authors.lastname: Xia
authors.forename: Ling
authors.initials: L
authors.lastname: Song
authors.forename: Shoulin
authors.initials: S
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Jin
authors.forename: Xinru
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics; D053713:Azoospermia / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics; D020440:Gene Duplication / Q000235:genetics; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007248:Infertility, Male / Q000235:genetics*; D008297:Male; D029589:Seminal Plasma Proteins / Q000235:genetics*; D013091:Spermatogenesis / Q000235:genetics
chemical_list: D029589:Seminal Plasma Proteins