5th Edition of International Neurology Conference 2026

Abstract

This study investigates the potential causal relationship between vitamin D deficiency and Tourette syndrome (TS) using Mendelian Randomization (MR). Previous research has suggested a link between low vitamin D levels and neurodevelopmental disorders, including TS, but the causal nature of this relationship remains unclear. A bidirectional two-sample MR approach was applied, utilizing single-nucleotide polymorphisms (SNPs) associated with vitamin D from a genome-wide association study (GWAS) of 418,691 individuals of European ancestry. TS risk data were obtained from the Psychiatric Genomics Consortium (4,819 cases, 9,488 controls). The analysis used the inverse variance weighted method to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Single SNP analyses identified a potential causal effect of vitamin D on TS risk for four SNPs (rs34937961, rs2847500, rs4939883, rs10788545), though overall MR analysis did not support a significant causal relationship. In reverse analysis, only one SNP (rs77313409) was associated with 25-hydroxyvitamin D levels. Multi-SNP MR analyses also did not support a causal link between TS and vitamin D. Our findings suggest no causal relationship between 25(OH)D levels and TS risk, indicating that increasing vitamin D supplementation may not reduce TS risk. Further research is needed to explore alternative pathways and validate these results.