Functional Variants of the RAD51 Gene Contribute to Susceptibility to Non-Syndromic Orofacial Clefts in a Han Chinese Population.

OBJECTIVES

Non-syndromic orofacial cleft (NSOFC) is a complex congenital disease caused by genetic and environmental factors, and its aetiology remains unclear. This study aims to investigate the association between potentially functional single-nucleotide polymorphisms (SNPs) in the RAD51 and E2F1 genes and the risk of developing NSOFC in the Han Chinese population.

MATERIALS AND

METHODS

A total of 200 NSOFC patients and 200 unrelated healthy controls of Han Chinese ancestry were recruited. Five candidate SNPs-rs1801320, rs45507396, rs7180135 and rs11855560 in the RAD51 gene, and rs3213180 in the E2F1 gene-were genotyped using the SNaPshot technique. Statistical and bioinformatics analyses were then performed to evaluate their associations with NSOFC.

RESULTS

RAD51 variants were significantly associated with NSOFC. The G allele of rs45507396 was identified as a risk allele, showing significant associations under four genetic models, while rs1801320 was significantly associated with NSOFC under three genetic models. Bioinformatics analyses predicted that hsa-miR-299-5p could bind to rs45507396, which is located within an ESE/ESS binding site and may induce exon skipping, potentially altering RAD51 coding. In contrast, rs1801320 was predicted to be a benign variant with no impact on splicing. Both SNPs are localised within ENCODE-annotated cis-regulatory elements (cCREs), with rs1801320 situated in a promoter-like cCRE and rs45507396 in an enhancer-like cCRE. Additionally, these variants may affect RNA-binding protein interactions, with rs1801320 influencing HNRNPA2B1 binding and rs45507396 affecting SFPQ binding. No significant associations with NSOFC were observed for rs7180135, rs11855560 or rs3213180.

CONCLUSION

This study is the first to identify RAD51 variants rs45507396 and rs1801320 as susceptibility loci for NSOFC in the Han Chinese population, providing novel genetic insights and a theoretical basis for further investigation into the molecular mechanisms of NSOFC.