Genomic and genetic variation in E2F transcription factor-1 in men with nonobstructive azoospermia

Abstract

Objective: To identify gene dosage changes associated with nonobstructive azoospermia (NOA) using array comparative genomic hybridization (aCGH).

Design: Prospective study.

Setting: Medical school.

Patient(s): One hundred ten men with NOA and 78 fertile controls.

Intervention(s): None.

Main outcome measure(s): The study has four distinct analytic components: aCGH, a molecular karyotype that detects copy number variations (CNVs); Taqman CNV assays to validate CNVs; mutation identification by Sanger sequencing; and histological analyses of testicular tissues.

Result(s): A microduplication at 20q11.22 encompassing E2F transcription factor-1 (E2F1) was identified in one of eight men with NOA analyzed using aCGH. CNVs were confirmed and in an additional 102 men with NOA screened using Taqman CNV assays, for a total of 110 NOA men analyzed for CNVs in E2F1. Eight of 110 (7.3%) NOA men had microduplications or microdeletions of E2F1 that were absent in fertile controls.

Conclusion(s): E2F1 microduplications or microdeletions are present in men with NOA (7.3%). Duplications or deletions of E2F1 occur very rarely in the general population (0.011%), but E2F1 gene dosage changes, previously reported only in cancers, are present in a subset of NOA men. These results recapitulate the infertility phenotype seen in mice lacking or overexpressing E2f1.

Keywords: Azoospermia; E2F1; NOA; array comparative genomic hybridization (aCGH); copy number variations (CNV); cryptorchidism; infertility.