Associations of variants in MTHFR and MTRR genes with male infertility in the Jordanian population Doaa S. Mfady a , May F. Sadiq a, ⁎, Omar F. Khabour b , AbdulFattah S. Fararjeh b , Aymen Abu-Awad c , Yousef Khader d a Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid 22110, Jordan b Department of Medical Laboratory Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan c AL-Hussein Medical City Hospital, Amman, Jordan. d Department of Public Health, Jordan University of Science and Technology, Irbid 22110, Jordan abstract article info Article history: Accepted 2 December 2013 Available online 12 December 2013 Keywords: MTHFR MTRR Single nucleotide polymorphism Jordan Infertility Male Folate pathway is expected to play an important role in spermatogenesis since it is involved in DNA synthesis, repair and methylation. The purpose of this study was to examine the association between male infertility and the MTHFR (C677T and A1298C) and MTRR (A66G) polymorphisms. A group of 300 males was recruited in this study from different Jordanian infertility clinics. Of these, 150 cases of infertile men that included oligozoosper- mia cases (n = 45), severe oligozoospermia (n = 71) and azoospermia (n = 34) were studied. The other 150 males were age matched fertile controls. Genotyping of MTHFR and MTRR polymorphisms was performed using PCR-RFLP technique. The results showed an association between MTHFR 677TT genotype and male infertil- ity (P b 0.05). However, the distribution of MTHFR A1298C and MTRR A66G genotypes were not different be- tween the fertile and infertile groups (P N 0.05). In addition, none of the examined polymorphisms was related to any of the semen parameters in the infertile group. In conclusion, this study showed that MTHFR C677T polymorphism is associated with male infertility in Jordanians. © 2013 Elsevier B.V. All rights reserved. 1. Introduction About 10 to 15% of married couples worldwide suffer from infertility in which 50% of it was attributed to the male partners (Sharma et al., 2004). The defect in spermatogenesis ranges from azoospermia with absence of mature germ cells to oligozoospermia with formation of low number of sperms. The causes of infertility in a considerable frac- tion of infertile male are unknown (Greenberg et al., 1978; Pryor et al., 1997), and were suggested to be complex due to the fact that the net- work of genes implicated in spermatogenesis and its regulation are lo- cated on different autosomes as well as on the sex chromosomes. In addition, male infertility is associated with different environmental fac- tors such as metabolic syndrome, obesity, and diet (Agbaje et al., 2007; Stillman et al., 1986; Teerds et al., 2011). A significant portion of the men infertility cases reported in different countries was hereditary, while the rest were proven unrelated to genetic factors (Greenberg et al., 1978; Tas et al., 1996). The folate metabolic pathway may play an important role in sper- matogenesis since folate deficiency is associated with hyperhomocys- teinemia that is considered as a risk factor for male infertility (Altmae et al., 2010). Folate is also related to DNA synthesis and methylation (Forges et al., 2008; Ravel et al., 2009; Wu et al., 2010), therefore, vari- ations in the genes encoding key enzymes involved in folate metabolism such as methylene tetrahydrofolatereductase (MTHFR) and methionine synthase reductase (MTRR) could be potential risk factors for infertility in men (Young et al., 2008). Two variants of MTHFR (C677T: rs1801133 and A1298C rs1801131) and one variant of MTRR (A66G; rs1801394) have clinical significance. MTHFR C677T is associated with different disorders, including cardiovascular and neuronal diseases and some cancers (Galbiatti et al., 2012; Marosi et al., 2012; van der Linden et al., 2006), while MTHFR A1298C is associated with cancer, pregnancy loss and hypertension (Alghasham et al., 2012; Lee and Song, 2010; Qin et al., 2013; Yan et al., 2012). In addition, the MTRR A66G polymorphism alters the enzyme activity significantly and is asso- ciated with different disorders including neural tube defects, colorectal cancer and coronary artery diseases (Gueant-Rodriguez et al., 2005; Ouyang et al., 2013; Zhou et al., 2012). The associations of MTHFR and MTRR polymorphisms with male in- fertility were examined in several populations from Asia, Europe and America (Gupta et al., 2011; Wei et al., 2012; Wu et al., 2012). However, such information was lacking from the Arab populations. In this study, the associations between male infertility and each of the three Gene 536 (2014) 40–44 Abbreviation: CI, confidence interval; DNA, deoxyribonucleic acid; EDTA, ethylene di- amine tetra-acetate; IVF, in vitro facilitated; MTHFR, methylene tetrahydrofolatereductase; MTRR, methionine synthase reductase; OR, odd ratio; PCR, polymerase chain reaction; RFLP, restriction fragment length Polymorphism; SNP, single nucleotide polymorphism. ⁎ Corresponding author at: Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid 21163, Jordan. Tel.: +962 077 617310; fax: +962 2 7211117. E-mail addresses: may@yu.edu.jo, maysadiq333@yahoo.com (M.F. Sadiq). 0378-1119/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.gene.2013.12.001 Contents lists available at ScienceDirect Gene journal homepage: www.elsevier.com/locate/gene