Cerebroretinal vasculopathy (CRV) and the related diseases hereditary endotheliopathy with retinopathy, neuropathy, and stroke (HERNS), hereditary vascular retinopathy (HVR) and hereditary systemic angiopathy (HSA) [subsequently combined as retinovasculopathy and cerebral leukodystrophy (RVCL)] are devastating autosomal-dominant disorders of early to middle-age onset presenting with a core constellation of neurologic and ophthalmologic findings. This family of diseases is linked by specific mutations targeting a core region of a gene. Frameshift mutations in the carboxyl-terminus of three prime exonuclease-1 (TREX1), the major mammalian 3' to 5' DNA exonuclease on chromosome 3p21.1-p21.3, result in a systemic vasculopathy that follows an approximately 5-year course leading to death secondary to progressive neurologic decline, with sometimes a more protracted course in HERNS. Neuropathological features include a fibrinoid vascular necrosis or thickened hyalinized vessels associated with white matter ischemia, necrosis and often striking dystrophic calcifications. Ultrastructural studies of the vessel walls often demonstrate unusual multilaminated basement membranes
