PREVALENCE OF FACTOR-V-LEIDEN MUTATION IN YOUNG-ADULTS WITH CEREBRAL-ISCHEMIA - A CASE-CONTROL STUDY ON 225 PATIENTS

Cerebral ischaemia in young adults is a well-recognised disease, and a pproximately half of the cases remain aetiologically unclear despite e xtensive investigations. Thrombophilias are known to cause a subset of ischaemic strokes in this population. The factor V Leiden (FVL) mutat ion, causing resistance to activated protein C, has recently been reco gnised as the most important genetic thrombophilia in the Western popu lation. Carriers of this gene mutation have a sevenfold increased risk of phlebothrombosis. We undertook this study to evaluate whether the FVL mutation constitutes a risk factor for juvenile cerebral ischaemia s. A total of 225 patients aged less than or equal to 45 years at onse t of cerebral ischaemia and 200 age-matched healthy controls were inve stigated. The overall frequency of heterozygosity for the FVL mutation did not differ significantly between patients (8.4%) and controls [6. 0%; odds ratio (OR) 1.4, 95% confidence interval (CI) 0.7-3.1]. In the subgroup of patients with cryptogenic cerebral ischaemia (n = 94), ho wever, a significantly higher frequency of this gene defect (15.9%) wa s found compared with the controls (OR 3.0, CI 1.3-6.6). Further trend s towards higher frequencies of the FVL mutation were found in patient s with patent foramen ovale (OR 1.9), individual (OR 2.1) or family hi story of previous thrombembolisms (OR 2.0), and in those aged 25 years at onset of disease (OR 1.9, all not significant). In conclusion, the FVL mutation is not a risk factor for cerebral ischaemia of the young . However, our results suggest that this gene mutation plays an aetiol ogical role in the subgroup of patients suffering from 'cryptogenic' i schaemic events.