Association of Tumor Necrosis Factor-α -308G>A, -238G>A and -376G>A polymorphisms with recurrent pregnancy loss risk in the Greek population

Background: Promoter region SNPs in TNF-α have been studied in association with Recurrent Pregnancy Loss (RPL) occurrence in various populations. Among them, -238G > A, -308G > A and - 376G > A have been frequently investigated for their potential role in recurrent abortions. The aim of the present study is to evaluate the correlation among TNF-α 238, TNF-α 308 and TNF-α 376 polymorphisms and recurrent pregnancy loss risk in Greek women.

Methods: This study included 94 Caucasian women with at least two miscarriages of unexplained aetiology, before the 20th week of gestation. The control group consisted of 89 Caucasian women of proven fertility, with no history of pregnancy loss. DNA samples were subjected to PCR amplification using specific primers. Sanger sequencing was applied to investigate the presence of TNF-α 238, TNF-α 308, TNF-α 376 polymorphisms in all samples.

Results: The TNF-α 238 and TNF-α 308 variants were both detected in RPL and control groups (7.45% vs 4.49 and 45.16% vs 36.73%, respectively), but with no statistically significant association (p-value 0.396 and 0.374, respectively). The TNF-α 376 variant was not detected at all in both control and RPL groups. When TNF-α 238 and TNF-α 308 genotypes were combined no association with RPL was detected (p-value = 0.694). In subgroup analysis by parity, RPL patients carrying the A allele reported less previous births.

Conclusions: This is the first study demonstrating TNF-α 238 and TNF-α 308 gene expression and the absence of TNF-α 376 variant in Greek women with RPL. However, no association emerged between each polymorphism studied and the occurrence of recurrent pregnancy loss. Accordingly, TNF-α -308G > A, -238G > A and -376G > A variants are not considered genetic markers for identifying women at increased risk of recurrent pregnancy loss in the Greek population.