Exploring Vascular Contributions to Migraine: Association Analysis of Small Vessel Disease Genetic Variants.

Background: Migraine is a complex neurovascular disorder with a substantial genetic component, yet many contributing loci remain poorly characterised. Methods: This study investigated the association between 21 biologically prioritised single nucleotide variants (SNVs) and migraine susceptibility in a case-control cohort of 548 individuals of European ancestry, of whom 304 (164 cases, 140 controls) remained after quality control and principal component analysis (PCA). Genotyping was performed using a targeted Sequenom MassARRAY platform, and substantial missingness (mean 30.3% per SNV) was addressed using multiple imputation by chained equations (MICE). Association testing was conducted using three complementary logistic regression frameworks: unadjusted single-variant analysis, covariate-adjusted marginal models, and a multivariable joint model incorporating all SNVs with L2 regularisation. Results: Across analyses, two variants in ASTN2 (rs1052053 and rs6478241) showed the most robust associations with migraine, surviving Bonferroni correction in the joint model (p = 0.001 and p = 0.002, respectively) and false discovery rate (FDR) correction in marginal models (q = 0.003 for both). A third variant, rs7304841 (12p12), demonstrated a risk-increasing effect that reached FDR significance in marginal analysis (q = 0.035) and remained nominally significant in the joint model. In contrast, rs62624978 in CTC1 showed a strong signal in unadjusted analysis (OR = 0.217, p = 0.0014) and remained nominally significant after adjustment (p = 0.011), although it did not survive multiple-testing correction in imputed models. The joint model demonstrated good discriminatory performance (AUC = 0.822), though this is not intended as a predictive tool. Biologically, implicated loci suggest contributions from both neuronal circuit organisation (ASTN2) and telomere and vascular maintenance pathways (CTC1), supporting a broader neurovascular model of migraine susceptibility. Conclusions: These findings are consistent with shared genetic architecture between migraine and microvascular dysfunction, potentially involving endothelial integrity, neurovascular coupling, and cortical excitability mechanisms.