Sneddon's syndrome (SS) is a rare non-inflammatory thrombotic vasculopathy characterized by the combination of cerebrovascular disease with livedo racemosa. The disease is Sneddon syndrome (Monarch Disease Ontology identifier MONDO_0008436). Also known as: Ehrmann-Sneddon syndrome, idiopathic livedo reticularis with systemic involvement, livedo racemosa-cerebrovascular accident syndrome, livedo reticularis-cerebrovascular accident syndrome.