Singh Kiran, Raman Rajiva
Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.
Indian J Exp Biol. 2005 Nov;43(11):1088-92.
The spermatogenesis locus azoospermia factor (AZF) in Yq11 has been delineated into three microdeletion intervals designated as AZFa, AZFb andAZFc. AZFc is the most frequently deleted region. We have studied 270 male infertile patients for various genetic disorders associated with infertile phenotype. In this study, we have presented results of our studies on Y-chromosome deletions, chromosomal abnormalities (Klinefelter syndrome) and histology of testis with the objective of seeing whether there were cases of gonosomic mosaicism and a causal correlation between the genetic disorder; and testicular aetiology could be drawn. In all the 13 cases of Y-chromosome microdeletion, AZFc region and DAZ gene were deleted, while no case of AZFa deletion was detected. This result was at variance with other reports from India, where a considerable fraction of cases showed deletion in AZFa region of the Y-chromosome. Both Y-deleted and non-Y-deleted cases revealed heterogeneous testicular phenotype with comparable severity. This disparity among testicular phenotype in cases with known genetic aetiology and even in cases of unknown aetiology can be attributed to different genetic backgrounds and effect of modifiers. Since male infertility is a multifactorial disorder, the contributions of environmental and occupational insults may not be underestimated.
Yq11上的精子发生位点无精子症因子（AZF）已被划分为三个微缺失区间，分别命名为AZFa、AZFb和AZFc。AZFc是最常被缺失的区域。我们研究了270名男性不育患者，以寻找与不育表型相关的各种遗传疾病。在本研究中，我们展示了关于Y染色体缺失、染色体异常（克兰费尔特综合征）和睾丸组织学的研究结果，目的是确定是否存在性染色体嵌合体病例，以及能否得出遗传疾病与睾丸病因之间的因果关系。在所有13例Y染色体微缺失病例中，AZFc区域和DAZ基因均被缺失，而未检测到AZFa缺失的病例。这一结果与印度的其他报道不同，在印度相当一部分病例显示Y染色体的AZFa区域存在缺失。Y染色体缺失和未缺失的病例均表现出具有相当严重程度的异质性睾丸表型。在已知遗传病因的病例甚至病因不明的病例中，睾丸表型的这种差异可归因于不同的遗传背景和修饰因子的作用。由于男性不育是一种多因素疾病，环境和职业性损伤的影响不可低估。
