However, in the homozygous state, the mutation is associated with increased morbidity and risk of thrombotic events [125] and the epidemiology of this mutation provided the strongest indications on the negative side effects of high EPO levels sustained by doping which, as experienced by the Chuvash, include enhanced likelihood of stroke, myocardial infarction, thrombosis, and an increase in total peripheral vascular resistance [126]. This evidence concerns the gene EPO and stroke disorder.