Single nucleotide polymorphism rs527236194 of the cytochrome B gene (MT-CYB) is associated with alterations in sperm parameters

Abstract

Background: The mitochondrial genome is substantially susceptible to mutations and has high polymorphism due to structural features, location, and lack of recombinant variability, as its inheritance is strictly maternal. All of these events can be accompanied by the accumulation of mitochondrial single nucleotide polymorphisms (mtSNPs) in the sperm. The aim of this research was to analyze the influence of mutations in the MT-CYB gene on sperm quality.

Methods and results: We conducted a case‒control study to identify mutations in the mitochondrial cytochrome B (MT-CYB) gene in men with asthenoteratozoospermia (89 cases) and oligoasthenoteratozoospermia (65 cases). The comparison group consisted of 164 fertile men. Somatic cell lysis followed by mtDNA extraction was conducted to analyze three mtDNA polymorphisms, rs28357373 (T15629C (Leu295=), rs527236194 (T15784C (p.Pro346=), rs2853506 (A15218G, p.Thr158Ala). Detection and genotyping of polymorphic loci in the MT-CYB gene was performed using the TaqMan allelic discrimination assay. To verify mutations in the MT-CYB gene, automated Sanger DNA sequencing was used. We found that rs527236194 was associated with asthenoteratozoospermia. rs28357373 in the MT-CYB gene did not show any polymorphism in the analyzed groups, which indicates a rare frequency of the TT genotype in our region. Rs28357373 and rs2853506 are not associated with male sperm abnormalities in the Volga-Ural region.

Conclusion: The association of the rs527236194 polymorphic variant with sperm parameter alterations suggests its role in the pathophysiology of male infertility and requires further investigation in larger samples.

Keywords: Asthenoteratozoospermia; Cytochrome B; Idiopathic infertility; Mitochondrial DNA; Mutations; Oligoasthenoteratozoospermia.