Single gene disorders causing ischaemic stroke.

Stroke is the third most common cause of death and the leading cause of long-term neurological disability in the world. Conventional vascular risk factors for stroke contribute approximately to only forty to fifty percent of stroke risk. Genetic factors may therefore contribute to a significant proportion of stroke and may be polygenic, monogenic or multi-factorial. Monogenic (single gene) disorders may potentially account for approximately one percent of all ischaemic stroke. Monogenic stroke disorders include conditions such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) and hereditary endotheliopathy, retinopathy, nephropathy and stroke (HERNS). In addition, other monogenic conditions such as sickle cell and Fabry disease also lead to stroke. These monogenic disorders cause either small vessel or large vessel stroke (or a combination of both) and serve as useful models for understanding and studying conventional stroke and cerebrovascular disease and its accompaniments such as vascular dementia.