Objective: To investigate microdeletions and palindrome complexes in the azoospermic factor (AZF) c regions of the Y chromosome, by polymerase chain reaction (PCR) with sequence-tagged site (STS) markers with known physical positions, after verification of the exact physical locations of candidate STSs and exclusion of those that would give ambiguous results on PCR.
Design: Retrospective STS deletion study in infertile Japanese men.
Setting: University hospital and reproductive clinic.
Patient(s): A total of 410 men with nonobstructive azoospermia and severe oligospermia (sperm concentrations of <5 x 10(6)/mL).
Intervention(s): Polymerase chain reaction was performed for all STS markers confirmed to be physically located in the partial AZFb and AZFc regions of the Y chromosome. All STSs were retrieved from the University of California at Santa Cruz database, and their location and specificity were verified.
Main outcome measure(s): Presence or absence of appropriately sized PCR products.
Result(s): Sixty-nine markers were retrieved, 32 of which were not specific to the long arm of the Y chromosome (Yq). The markers retained for test use were contiguous deletions classified as P1+P2 (AZFc) or P3 proximal/P1 (AZFb+c). The prevalence of accurately mapped microdeletions was 5.1% (21 of 410) in this patient population.
Conclusion(s): Although noncontiguous deletions were observed, considerable confusion remained until the genome sequence was finally determined because many of the STSs were either repetitive sequences or polymorphic between individuals or races.