Y chromosome analysis of infertile men and their sons conceived through intracytoplasmic sperm injection: vertical transmission of deletions and rarity of de novo deletions

Objective: To determine the prevalence and type of Yq microdeletions in 86 consecutive men that fathered 99 sons by intracytoplasmic sperm injection (ICSI) and to determine the incidence of vertical transmission and de novo deletions in these boys. Design: Prospective clinical observational study. Setting: Genetics laboratory associated with a university IVF unit. Patient(s): Eighty-six consecutive infertile men presenting to an IVF clinic and their 99 ICSI-conceived sons. Fifty of the 86 men (58%) had idiopathic seminiferous tubule failure (STF); the remainder had a variety of other clinical indications for ICSI. Intervention(s): Collection of peripheral and cord blood samples. Main Outcome Measure(s): The Yq genetic status of fathers who underwent ICSI and of their sons by the presence or absence of 22 Y-specific markers covering the four azoospermia factor (AZF) subregions. Result(s): Yq deletions of the AZFd/c region were detected in two (6.9%) of 29 azoo- or severely oligospermic men with STF. Identical deletions were found in their respective sons. No de novo deletions were detected in the remaining 97 sons conceived by men without deletions. Conclusion(s): The detection of Yq deletions only in men with severe STF is consistent with previous studies, with the AZFd/c region being most commonly affected. This study demonstrates the vertical transmission of these Yq deletions through the use of ICSI and supports the notion that, in most cases, Yq deletions will be inherited by male offspring. The absence of de novo Yq deletions in the male offspring indicates that these events are rare following ICSI in men with both STF and other common male factor indications.