AZFb microdeletions and oligozoospermia-which mechanisms?

Objective: To characterize the deletion patterns and its breakpoints in oligozoospermic patients presenting AZFb and AZFc microdeletions and to understand the recombination mechanisms underlying these microdeletions. Design: Case report. Setting: Genetics Department of Faculty of Medicine of Porto, Porto, Portugal. Patient(s): Two men with severe oligozoospermia and two men with nonobstructive azoospermia identified as having different AZFb+c deletion patterns via Y chromosome microdeletion analysis. Intervention(s): Definition of microdeletions and the fine characterization of the respective breakpoints by sequence-tagged sites (STS) polymerase chain reaction (PCR) and single-nucleotide variant (SNV) PCR. Main Outcome Measure(s): Study of the fine structure of the Y-chromosome and discussion of the putative mechanisms involved in each microdeletion pattern. Result(s): From the four patients studied, three deletion patterns were identified: IR4/distal-P2 (25%; 1 of 4), P5/proximal-P1 (50%; 2 of 4), and P5/distal-P1 (25%; 1 of 4). Although severe oligozoospermia is normally associated with AZFc, a complete AZFb deletion was found in one case. Conclusion(s): Analysis of these patients has revealed a new putative region that may be involved in spermatogenesis conservation. (Fertil Steril (R) 2012;97:858-63. (C)2012 by American Society for Reproductive Medicine.)