Y chromosome gr/gr deletions are a risk factor for low semen quality

Hum Reprod. 2009 Oct;24(10):2667-73. doi: 10.1093/humrep/dep243. Epub 2009 Jul 14.


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 10(6)/ml versus 53 x 10(6)/ml, P = 0.017), total sperm count (median 108 x 10(6) versus 152 x 10(6), P = 0.006) and total motile sperm count (median 20 x 10(6) versus 50 x 10(6), 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.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Adult
  • Azoospermia / genetics
  • Chromosomes, Human, Y / genetics*
  • Cohort Studies
  • Humans
  • Male
  • Oligospermia / genetics
  • Risk Factors
  • Semen / physiology*
  • Semen Analysis
  • Sequence Deletion*