Liver pathology in retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations: vasculopathic disease beyond nodular regenerative hyperplasia.

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a rare autosomal dominant disease resulting from a frame-shift mutation in TREX1, an intracellular 3'-5' exonuclease 1. Hepatic findings include an elevated alkaline phosphatase (ALP) and nodular regenerative hyperplasia (NRH). Affected individuals typically succumb to brain lesions before clinically apparent hepatic manifestations; thus, little else is known about the hepatic pathology. Autopsy reports and a liver section from each (n = 11) of three unrelated kindreds with the most common mutation in TREX1 (V235Gfs∗6) were studied with standard and immunohistochemical stains. Cases were compared with "normal liver" controls from similar autopsy years. Cases consisted of six men and five women who died at a median age of 50 yr (range, 41-60 yr.). Seven had elevated ALP. Two had liver atrophy. Foci of NRH were variably detected in all. Inhomogeneous distribution of other findings included patternless parenchymal fibrous bands, approximation of vascular structures, and commonly, architectural changes of vascular structures. Only bile duct epithelia were unaffected. In addition, small trichrome-positive nodules were found along vein walls or isolated in the parenchyma. Rare foci of non-NRH hepatocytic nodules were noted in 3. Increased CD34 and altered α-SMA IHC expression were variably noted. Periportal ductules and perivenular K7 IHC expression were increased to unpredictable degrees. The extensive but inhomogeneous histopathologic findings in livers of autopsied patients with RVCL-S appear to involve hepatic vascular structures. These findings validate inclusion of vascular liver involvement beyond NRH in this complex hereditary disorder.

Lesion evolution and neurodegeneration in RVCL-S: A monogenic microvasculopathy.

OBJECTIVE: To characterize lesion evolution and neurodegeneration in retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) using multimodal MRI. METHODS: We prospectively performed MRI and cognitive testing in RVCL-S and healthy control cohorts. Gray and white matter volume and disruption of white matter microstructure were quantified. Asymmetric spin echo acquisition permitted voxel-wise oxygen extraction fraction (OEF) calculation as an in vivo marker of microvascular ischemia. The RVCL-S cohort was included in a longitudinal analysis of lesion subtypes in which hyperintense lesions on fluid-attenuated inversion recovery (FLAIR), T1-postgadolinium, and diffusion-weighted imaging were delineated and quantified volumetrically. RESULTS: Twenty individuals with RVCL-S and 26 controls were enrolled. White matter volume and microstructure declined faster in those with RVCL-S compared to controls. White matter atrophy in RVCL-S was highly linear (ρ = -0.908, p < 0.0001). Normalized OEF was elevated in RVCL-S and increased with disease duration. Multiple cognitive domains, specifically those measuring working memory and processing speed, were impaired in RVCL-S. Lesion volumes, regardless of subtype, progressed/regressed with high variability as a function of age, while FLAIR lesion burden increased near time to death (p < 0.001). CONCLUSION: RVCL-S is a monogenic microvasculopathy affecting predominantly the white matter with regard to atrophy and cognitive impairment. White matter volumes in RVCL-S declined linearly, providing a potential metric against which to test the efficacy of future therapies. Progressive elevation of white matter OEF suggests that microvascular ischemia may underlie neurodegeneration in RVCL-S.