Cytochrome P450 1A1 gene polymorphism and their haplotypes as a susceptibility factors for oligozoospermia in Iraqi men

Abstract

In the present study we investigate the association of CYP1A1*2A (rs4646903) and CYP1A1*2C (rs1048943) SNPs in CYP1A1 gene with oligozoospermia in a sample of Iraqi patients. Blood samples were collected from 50 oligozoospermic patients and 50 apparently healthy subjects (Controls). Genomic DNA was extracted from blood samples by using protocol in EasyPure® blood genomics DNA kit. Genotyping was performed by RT-PCR HRM using rotor gene (Qiagen). No significant differences were noted between study groups as related with semen volume and semen pH. The values of sperm count, normal sperms, sperm motility A, sperm motility B and sperm motility C were in oligozoospermic patients group significantly (p≤0.01) lower than in apparently healthy subjects group (7.22 versus 37.78 million, 24.3 versus 44.64 %, 0.10 versus 8.0%, 7.5 versus 21% and 17.8 versus 30.5%, respectively). While, the percentage of abnormal sperm and immotile sperm were in oligozoospermic patients group significantly (p≤0.01) higher than in apparently healthy subjects group (75.7 versus 55.36% and 74.6 versus 40.3%, respectively). As related with rs4646903 SNP of CYP1A1 gene, AA genotype represent a protective factor against the incidence of oligozoospermia, whereas, GG genotype represent a risk factor for oligozoospermia incidence. The percentage of A allele was lower in oligozoospermic patients than in apparently healthy subjects (0.31 versus 0.57, respectively), in contrast, G allele frequency was in oligozoospermic patients higher than in apparently healthy subjects (0.69 versus 0.43, respectively). As related with rs1048943 SNP of CYP1A1 gene, no significant differences were noted between study groups as related with all genotypes and the T allele frequencies were 0.67 and 0.70 and A allele were 0.33 and 0.30 for apparently healthy subjects and oligozoospermic patients, respectively. The results of haplotype defined by rs4646903 and rs1048943 SNPs showed that AT haplotype represent a protective factor against the incidence of oligozoospermia while GT haplotype was represent a risk factor for oligozoospermia incidence in Iraqi patients. Also, both AT/AT and AT/GA haplotype combinations represent as a protective factor against oligozoospermia incidence, whereas, AT/GT and GT/GT haplotype combinations were represent as a risk factor for oligozoospermia incidence in Iraqi patients. In conclusion, the results of the present study support that the CYP1A1 rs4646903 polymorphism (GG genotype) might contribute to individual susceptibility to oligozoospermia in a sample of Iraqi patients.