P-026 Lack of association between single polymorphic variants of the mitochondrial nicotinamide adenine dinucleotide dehydrogenase 3, and 4L (MT-ND3 and MT-ND4L) and male infertility

Abstract

Abstract Study question Is there any association between male infertility and the polymorphic variants of Mitochondrial Nicotinamide Adenine Dinucleotide Hydride dehydrogenase (NADH) Subunit 3 and 4L (MT-ND3 and MT-ND4L)? Summary answer The genotypes and allele frequencies of the study population have shown a lack of statistically significant association between MT-ND3 and MT-ND4L SNPs and male infertility. What is known already Male infertility is a multifactorial condition associated with different genetic abnormalities in at least 15%–30% of cases. The rate of mutations in the mtDNA is high due to the lack of histones and DNA repair mechanisms. Moreover, mtDNA is more vulnerable compared to nuclear DNA due to the lack of an efficient repairing system and high exposure to oxidative species produced by the mitochondria. Eventually, this leads to abnormal sperm function, structure and even infertility. Study design, size, duration Prospective study was carried out between 2018 and 2019. 112 semen samples were collected in this study. Participants/materials, setting, methods The present study was carried out at the department of Obstetrics and Gynecology, University of Saarland,Germany. After semen analysis, samples were purified. Mitochondrial DNA was extracted using a QIAamp DNA Mini Kit, then, the mitochondrial DNA was amplified by using the REPLI-g Mitochondrial DNA Kit. Polymerase chain reaction (PCR) was used to amplify MT-ND3 and MT-ND4L genes. After that samples were purified and sequenced using the Sanger method in the Microsynth Seq Lab in Germany. Main results and the role of chance Eight single nucleotide polymorphisms (SNPs) in MT-ND3 (rs2853826, rs28435660, rs193302927, rs28358278, rs41467651, rs3899188, rs28358277 and rs28673954) and seven SNPs in MT-ND4L (rs28358280, rs28358281, rs28358279, rs2853487, rs2853488, rs193302933 and rs28532881) were detected and genotyped. The genotypes and allele frequencies of the study population have shown a lack of statistically significant association between MT-ND3 and MT-ND4L SNPs and male infertility. Besides, no statistically significant difference was found between the asthenozoospermia, oligozoospermia, teratozoospermia, asthenoteratozoospermia, oligoasthenoteratozoospermia and oligoteratozoospermia subgroups of subfertile males. However, rs28358278 genotype of the MT-ND3 gene was reported in the subfertile group but not in the fertile group, which implies a possible role of this SNP in male infertility. Limitations, reasons for caution The size number of the study samples. Wider implications of the findings Further studies are required to evaluate these findings. Moreover, the subfertile individuals who exhibit a polymorphism at rs28358278 require further monitoring and evaluation. Trial registration number Basic Science