Evaluation of FOXP3 Exons 2 and 7 Variants in Recurrent Pregnancy Loss among South Indian Women.

Introduction: One to two percent of women worldwide experience recurrent pregnancy loss (RPL), defined as the loss of two or more consecutive pregnancies before 20 weeks of gestation. Genetic factors, including variations in the FOXP3 gene, have been implicated in the unexplained etiology of RPL. This study aimed to identify and characterize novel genetic variants in exons 2 and 7 of the FOXP3 gene in South Indian women with idiopathic RPL and to analyze their potential impact on protein structure.

Materials and methods: This case-control study involved DNA extraction from 300 participants, including 150 recurrent pregnancy loss (RPL) cases and 150 non-recurrent pregnancy loss (NRPL) controls. Polymerase chain reaction (PCR) and Sanger sequencing were used to identify genetic variants. The identified single-nucleotide polymorphisms (SNPs) were analyzed for frequency differences between the RPL and control groups. Additionally, bioinformatics tools were employed to assess the structural impact of the identified mutations on the FOXP3 protein.

Results: Seven novel single-nucleotide polymorphisms (SNPs) were identified, with four SNPs (-11InsT, 206G>A in exon 2, and 433InsT, 726A>T in exon 7), showing significant frequency variations between RPL and NRPL groups. The modeled structures of FOXP3 apo and mutant proteins displayed similar structural features, including a DNA-binding domain. Molecular dynamics simulation studies revealed comparable stability between the apo and mutant forms of FOXP3.

Discussion: The identified mutations in the FOXP3 gene can potentially disrupt its critical immune- regulatory functions, leading to impaired immune tolerance during pregnancy, a key factor in the development of RPL. These mutations may alter the activity or stability of regulatory T cells, which are essential for maintaining pregnancy by preventing immune rejection of the fetus.

Conclusion: These findings provide new insights into the genetic underpinnings of idiopathic RPL and underscore the importance of genetic testing for a better understanding of this condition.