Inherited Thrombophilia in Early-Onset Carotid Stenosis: A Comparative Study of Dissection, Atherosclerosis, Fibromuscular Dysplasia, and Other Etiologies

Background: Carotid artery stenosis is a recognized cause of ischemic stroke in older adults but is rare in individuals under 50, where distinct etiologies such as dissection, fibromuscular dysplasia (FMD), or genetic predispositions are often implicated. The role of inherited thrombophilia in young-onset carotid stenosis remains unclear. Objective: To assess the prevalence and etiologic associations of selected inherited coagulation-related gene variants in young adults with carotid artery stenosis. Methods: This single-center observational study included 42 patients under 50 years of age with ≥50% extracranial carotid stenosis. Patients were categorized into four etiologic subgroups: dissection/web, atherosclerosis, FMD, and other. Thrombophilia testing included prothrombin G20210A, factor V Leiden, MTHFR C677T/A1298C, PAI-1 4G/5G, factor XIII V34L, and homocysteine levels. Group comparisons were made using Fisher's exact or chi-square tests. Results: No statistically significant differences were observed in the distribution of thrombophilia-related markers among the etiologic groups. Although PAI-1 4G/5G polymorphism and elevated homocysteine levels were numerically more frequent in the atherosclerosis group, these trends did not reach statistical significance. Conclusion: In this modestly sized cohort, inherited coagulation-related gene variants did not differ significantly across carotid stenosis subtypes in young adults. Routine broad panel testing may offer limited etiologic discrimination. Instead, a context-driven, selective testing approach especially considering antiphospholipid syndrome may be more appropriate.