Genomic Validation in the UK Biobank Cohort Suggests a Role of C8B and MFG-E8 in the Pathogenesis of Trigeminal Neuralgia.

Trigeminal neuralgia (TN) is a severe facial pain disease of uncertain pathophysiology and unclear genetic background. Although recent research has reported a more important role of genetic factors in TN pathogenesis, few candidate genes have been proposed to date. The present study aimed to identify independent genetic variants in the protein-coding genes associated with TN. We focused on genes previously linked to TN based on the results of four proteomic studies conducted by our research team. The goal was to validate these findings on the genetic level to enhance our understanding of the role of genetics in TN. The study is based on the participants from UK Biobank cohort. Following quality control, 175 independent single nucleotide polymorphisms (SNPs) in 17 genes were selected. The study sample comprised of diagnosed TN cases (N = 555) and randomly matched controls (N = 6245) based on specific criteria. Two SNPs corresponding to C8B rs706484 [odds ratio (OR) (95% confidence interval (CI)): 1.357 (1.158-1.590); p: 0.00016] and MFG-E8 rs2015495 [OR (95% CI): 1.313 (1.134-1.521); p: 0.00028] showed significant positive association with TN, indicating a positive effect of the SNP alleles on gene expression and disease risk. Interestingly, both SNPs are Expression Quantitative Trait Loci (eQTLs), and are associated with changes in the expression activity of their corresponding gene. Our findings suggest novel genetic associations between C8B, a key component of the complement system, and MFG-E8, which plays a role in regulating neuroinflammation, in relation to TN. The identified genetic variations may help explain why some individuals develop TN while others do not, indicating a potential genetic predisposition to the condition.