Hum. Reprod. Advance Access originally published online on July 14, 2009
Human Reproduction 2009 24(10):2667-2673; doi:10.1093/humrep/dep243
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Y chromosome gr/gr deletions are a risk factor for low semen quality
1 Centre for Reproductive Medicine, Department of Obstetrics and Gynecology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands 2 Duke-NUS Graduate Medical School, Singapore, Singapore
3 Correspondence address. Tel: +31-20-5663090; Fax: +31-20-5669206; E-mail: s.repping{at}amc.uva.nl
BACKGROUND: Subfertility affects one in eight couples. In up to 50% of cases, the male partner has low semen quality. Four Y chromosome deletions, i.e. Azoospermia factor a (AZFa), P5/proximal-P1 (AZFb), P5/distal-P1 and AZFc deletions, are established causes of low semen quality. Whether a recently identified partial AZFc deletion, the gr/gr deletion, also causes low semen quality is at present unclear.
METHODS: We used a dual approach to review the effect of the gr/gr deletion on semen quality. First, we conducted a systematic review and meta-analysis of previous association studies, to compare the prevalence of gr/gr deletions between azoo-/oligozoospermic men and normozoospermic men. Secondly, we studied a cohort of 1041 male partners of subfertile couples unselected for semen quality. We employed a cross-sectional design by screening all men for the gr/gr deletion and comparing the semen quality of men with and without the gr/gr deletion.
RESULTS: Seven studies were included in the meta-analysis. The gr/gr deletion was significantly more prevalent among azoo-/oligozoospermic men than among normozoospermic men (OR 2.4, 95% CI 1.75–3.30). In our cohort, 25 men carried a gr/gr deletion. Men with this genotype had a lower sperm concentration (median 34 x 106/ml versus 53 x 106/ml, P = 0.017), total sperm count (median 108 x 106 versus 152 x 106, P = 0.006) and total motile sperm count (median 20 x 106 versus 50 x 106, P = 0.010) than men without the gr/gr deletion.
CONCLUSION: Y chromosome gr/gr deletions significantly reduce sperm counts and are thus associated with low semen quality.
Key words: Y chromosome/gr/gr deletion/spermatogenesis/semen quality/male infertility
Submitted on January 29, 2009; resubmitted on June 9, 2009; accepted on June 12, 2009.