The plasma glycoprotein afamin has been previously identified as an alternative carrier protein for vitamin E in extravascular fluids such as plasma and cerebrospinal, ovarian follicular, and seminal fluids. However, to date, no study has established a relationship between afamin levels and infertility in women or men. The purposes of our study were (i) to assess the level of afamin in serum and seminal fluids in infertile men compared to healthy controls and (ii) to study the association between polymorphisms in afamin genes and male infertility. This observational, prospective study evaluated the afamin levels in serum and seminal fluids from infertile men (n = 39) and compared them to those in healthy controls (n = 30). We studied the association between single-nucleotide polymorphisms (SNPs) in the 5`-untranslated region (5`-UTR) of the afamin gene and infertility and analyzed a total of 1000 base pairs from the untranslated region of the afamin gene. Subjects with low sperm motility and low sperm concentration had higher median seminal afamin (18.9 ± 2.9 ng/mg of proteins) and serum afamin concentrations (24.1 ± 4.0 ng/mg of proteins) than subjects with normal sperm parameters (10.6 ± 1.4 ng/mg of proteins) (p < 0.02) (15.6 ± 1.4 ng/mg of proteins) (p < 0.002). A total of five different polymorphisms were found, including one deletion and four single-nucleotide polymorphisms (SNPs). A new transversion (A/T) (position 4:73481093) was identified in an oligoasthenoteratozoospermic patient and was associated with high levels of afamin in plasma and seminal fluids. The prevalence of this variant in our study in the case homozygous for TT is 0.985 (98.5%), and in the case heterozygous for TA is 0.015 (1.5%). Our results suggest that genetic variations in afamin might be associated with male infertility. These findings could significantly enhance our understanding of the molecular genetic causes of infertility.
Keywords: Afamin; Male infertility; Oligoasthenoteratozoospermia; Polymorphisms genes; Seminal plasma.