Variants in the Antioxidant Gene (catalase) and its Correlation with Idiopathic Male Infertility in Iraqi Population

Abstract

Infertility is a multifactorial and polygenic disease. A vast majority of infertility is still unexplained despite modern diagnostic techniques. Catalase (CAT), the key enzyme for high H2O2 elimination, constitutes, along with superoxide dismutase (SOD) and gluthatione peroxidase (GPX), the main enzymatic antioxidant system. Catalase enzyme plays an important role in seminal antioxidant defense and is present in seminal plasma at high concentrations. Low concentrations of catalase enzyme in seminal plasma have been related with male infertility. The aim of the study was to investigate the status of the antioxidant enzyme; catalase in clinically diagnosed infertile males and find the potential association of CAT gene variant in the promoter region  (rs1001179 [−262C/T] and  rs7943316[ −21 A/T] and other CAT gene variant CAT rs1049982 [T/C], and CAT rs12270780 [G/A] and their association with the gene expression of the CAT gene. The study consisted of 100 clinically diagnosed infertile males (50 oligozoospermia and 50 asthenozoospermia) and 50 fertile volunteers. Polymerase chain reaction followed by sequencing were performed for genotyping of catalase variants. mRNA level of Catalase was analyzed by using semi quantitative technique.  There was no significant difference in allele frequencies and genotype distribution for all SNPs. It was concluded that  gene expression shows little increase in the level of CAT mRNA of fertile samples when compared to infertile samples.