Maternal RFC1 Gene Polymorphisms and Neural Tube Defects: A Case-Control Study in Ethiopia

Etiologies of neural tube defects (NTDs) are multifactorial. Genetic, epigenetic and environmental factors may contribute to their reported variation in prevalence across the globe. Ethiopia has among the highest reported NTD prevalence globally, making investigation of genetic determinants in this high-risk population particularly important for advancing the understanding of NTD etiology. Genes involved in folate metabolism, such as the reduced folate carrier 1 (RFC1), have been investigated for the potential associations with NTDs, but findings throughout the literature remain inconsistent and inconclusive.

The aim of this study was to determine an association of RFC-1 polymorphism at rs1131596 and rs1051266 loci (functional variants previously implicated in folate transport efficiency and NTD susceptibility) among mothers with the occurrence of NTDs in their offspring in Ethiopia.

A case-control study involving 250 mothers (187 controls and 63 cases) of children with or without NTDs was conducted in Addis Ababa, Ethiopia from April 2022, to September 2024. A total of 250 maternal whole blood samples were systematically collected and subjected to genetic analysis at loci rs1131596 and rs1051266 by polymerase chain reaction (PCR) and Sanger sequencing.

Detection of heterozygous (TC) and homozygous (CC) genotypes for SNP rs1131596 (-43T>C) in the RFC1 gene was 27.2%, with heterozygous (TC) comprising 10.4% and homozygous (CC) 16.8%. In contrast, for the rs1051266 (80A>G), the prevalence of the AG polymorphism was 28% while the GG polymorphism was 16.4%, resulting in a cumulative prevalence of 44.4%. The presence of maternal RFC-1 polymorphism at these two locations were not associated with significantly (p = 0.601 & p = 0.225 respectively) higher odds for NTD births.

This study did not reveal significant association between maternal RFC1 gene polymorphisms and NTD-affected births. Comprehensive whole-genome sequencing of affected off-spring is essential to identify specific mutations or polymorphisms that may individually or collaboratively affect the risk of NTDs in the Ethiopian context.