HERNS syndrome (Orphanet_63261, an Orphanet rare-disease nomenclature identifier) can be described as follows. Hereditary endotheliopathy with retinopathy and stroke (HERNS) is a phenotypic variant of a group of inherited small vessel disorders known as retinal vasculopathy and cerebral leukodystrophy (RVCL; see this term) and characterized by strokes, vision loss, pseudotumours, seizures, motor and sensory deficits, headaches and occasionally renal disease. Also known as: Hereditary endotheliopathy - retinopathy - nephropathy - stroke.