Genetic Association Between Blood Metabolites and Craniosynostosis: A Mendelian Randomization Study

Craniosynostosis is a congenital disorder characterized by the premature fusion of cranial sutures, leading to abnormal skull development and potential neurodevelopmental complications. The role of metabolic influences in craniosynostosis remains underexplored. This study investigates the causal relationship between specific blood metabolites and the risk of craniosynostosis using a 2-sample Mendelian randomization (MR) approach. Genetic instruments were selected from a genome-wide association study on blood metabolites and craniosynostosis data from the FinnGen database. The MR analysis was conducted using inverse variance weighted regression as the primary method, with MR-Egger and weighted median methods as sensitivity analyses. Additional tests for pleiotropy and heterogeneity were performed to validate the robustness of the findings. The analysis identified significant associations between elevated levels of gamma-glutamylglycine [odds ratio (OR) = 2.379, 95% CI = 1.261-4.488, P = 0.007], N6-acetyllysine (OR = 2.731, 95% CI = 1.081-6.901, P = 0.034), phosphocholine (OR = 2.205, 95% CI = 1.226-3.658, P = 0.038) and glycine (OR = 2.118, 95% CI = 1.226-3.658, P = 0.007) with an increased risk of craniosynostosis. Conversely, higher levels of 3-hydroxy-2-methylpyridine sulfate (OR = 0.411, 95% CI = 0.1717-0.988, P = 0.047) and 5,6-dihydrothymine (OR = 0.293, 95% CI = 0.098-0.876, P = 0.028) were associated with reduced risk. Sensitivity analyses confirmed the robustness of these findings, with no significant evidence of pleiotropy or heterogeneity detected. This study provides evidence that specific blood metabolites may causally influence the risk of craniosynostosis, suggesting potential metabolic pathways that could be targeted for therapeutic intervention. These findings help to develop metabolite-based strategies for the prevention and treatment of craniosynostosis.