Retinal vasculopathy with cerebral leukodystrophy: Clinicopathologic features of an autopsied patient with a heterozygous TREX 1 mutation

Abstract

Retinal vasculopathy with cerebral leukodystrophy (RVCL) is an autosomal-dominant disorder involving the cerebral, retinal, renal, and other systemic microvessels due to frameshift mutations in the TREX1 gene. Under physiological conditions, the TREX1 protein is localized in the cellular cytoplasm and perinuclear area, but translo-cates into the nucleus in response to oxidative DNA damage. It has been speculated that aberrant localization of the protein may be associated with systemic microangiopathy in patients with RVCL. However, cellular expression of TREX1 in the brain and visceral organs of patients with RVCL has been unclear. Here, we report the clinicopathologic features of an autopsied patient with a heterozygous T249fs mutation in TREX1. The patient showed the clinical phenotype of vasculopathy with retinopathy, nephropathy, and stroke. CT with contrast enhancement demonstrated a tumorous lesion in the subcortical white matter. Histologically, the lesion consisted of confluent foci of necrosis with calcification and fibrous thickening of small vessel walls. TREX1 immunohistochemistry demonstrated positivity in the nuclei of cells in the CNS and visceral organs, indicating aberrant localization of the truncated protein, and the expression was remarkable in oligodendrocytes within the lesion, suggesting possible involvement of the protein in the pathomechanism of vasculopathy leading to white matter degeneration.