Quantitative trait analysis suggests human DAZL may be involved in regulating sperm counts and motility

A prospective study was carried out to identify the association of the DAZL (deleted in azoospermia-like) gene with major semen parameters in 210 men with normal and 467 men with abnormal semen parameters. Primer extension analysis for single nucleotide polymorphisms (SNP) of DAZL and quantitative trait analysis on the association of allele/genotype frequencies, linkage disequilibrium characteristics and DAZL haplotypes with semen parameters were investigated. Of five SNP (260A→G, 386A→G, 520+34c→a, 584+28c→t and 796+36g→a) screened, 386A→G was significantly correlated with sperm count (P < 0.0001) and motility (P < 0.005) and 584+28c→t was marginally correlated with sperm morphology. After excluding 520+34c→a, which was not in the Hardy–Weinberg equilibrium, the major haplotypes consisted of four SNP. One haplotype (260A→G (major allele), 386A→G (major allele), 584+28c→t (minor allele) and 796+36g→a (major allele)) was significantly associated with sperm count (P = 0.003) and motility (P = 0.04). This study suggests DAZL may be involved in regulating sperm counts, motility and possibly morphology.