Inherited C-terminal TREX1 variants disrupt homology-directed repair to cause senescence and DNA damage phenotypes in Drosophila, mice, and humans.

Age-related microangiopathy, also known as small vessel disease (SVD), causes damage to the brain, retina, liver, and kidney. Based on the DNA damage theory of aging, we reasoned that genomic instability may underlie an SVD caused by dominant C-terminal variants in TREX1, the most abundant 3'-5' DNA exonuclease in mammals. C-terminal TREX1 variants cause an adult-onset SVD known as retinal vasculopathy with cerebral leukoencephalopathy (RVCL or RVCL-S). In RVCL, an aberrant, C-terminally truncated TREX1 mislocalizes to the nucleus due to deletion of its ER-anchoring domain. Since RVCL pathology mimics that of radiation injury, we reasoned that nuclear TREX1 would cause DNA damage. Here, we show that RVCL-associated TREX1 variants trigger DNA damage in humans, mice, and Drosophila, and that cells expressing RVCL mutant TREX1 are more vulnerable to DNA damage induced by chemotherapy and cytokines that up-regulate TREX1, leading to depletion of TREX1-high cells in RVCL mice. RVCL-associated TREX1 mutants inhibit homology-directed repair (HDR), causing DNA deletions and vulnerablility to PARP inhibitors. In women with RVCL, we observe early-onset breast cancer, similar to patients with BRCA1/2 variants. Our results provide a mechanistic basis linking aberrant TREX1 activity to the DNA damage theory of aging, premature senescence, and microvascular disease.

Accuracy of a machine learning method based on structural and locational information from AlphaFold2 for predicting the pathogenicity of TARDBP and FUS gene variants in ALS.

BACKGROUND: In the sporadic form of amyotrophic lateral sclerosis (ALS), the pathogenicity of rare variants in the causative genes characterizing the familial form remains largely unknown. To predict the pathogenicity of such variants, in silico analysis is commonly used. In some ALS causative genes, the pathogenic variants are concentrated in specific regions, and the resulting alterations in protein structure are thought to significantly affect pathogenicity. However, existing methods have not taken this issue into account. To address this, we have developed a technique termed MOVA (method for evaluating the pathogenicity of missense variants using AlphaFold2), which applies positional information for structural variants predicted by AlphaFold2. Here we examined the utility of MOVA for analysis of several causative genes of ALS. METHODS: We analyzed variants of 12 ALS-related genes (TARDBP, FUS, SETX, TBK1, OPTN, SOD1, VCP, SQSTM1, ANG, UBQLN2, DCTN1, and CCNF) and classified them as pathogenic or neutral. For each gene, the features of the variants, consisting of their positions in the 3D structure predicted by AlphaFold2, pLDDT score, and BLOSUM62 were trained into a random forest and evaluated by the stratified fivefold cross validation method. We compared how accurately MOVA predicted mutant pathogenicity with other in silico prediction methods and evaluated the prediction accuracy at TARDBP and FUS hotspots. We also examined which of the MOVA features had the greatest impact on pathogenicity discrimination. RESULTS: MOVA yielded useful results (AUC ≥ 0.70) for TARDBP, FUS, SOD1, VCP, and UBQLN2 of 12 ALS causative genes. In addition, when comparing the prediction accuracy with other in silico prediction methods, MOVA obtained the best results among those compared for TARDBP, VCP, UBQLN2, and CCNF. MOVA demonstrated superior predictive accuracy for the pathogenicity of mutations at hotspots of TARDBP and FUS. Moreover, higher accuracy was achieved by combining MOVA with REVEL or CADD. Among the features of MOVA, the x, y, and z coordinates performed the best and were highly correlated with MOVA. CONCLUSIONS: MOVA is useful for predicting the virulence of rare variants in which they are concentrated at specific structural sites, and for use in combination with other prediction methods.

[ATTRv amyloidosis with early improvement demonstrated by the 6-minute walk test following Patisiran therapy: a case report].

We report the case of a 65-year-old man who gradually developed numbness in both hands, lower limb muscle weakness and atrophy, and orthostatic hypotension over two and a half years. These symptoms indicated hereditary ATTR amyloidosis (ATTRv amyloidosis), and the final diagnosis was established through proof of TTR gene mutation (V30M). We initiated patisiran therapy, and a continuous 6-minute walking test performed 3 weeks from the start of therapy demonstrated improvement in the walking distance. This is a single case report showing the improvement in the motor and sensory function on administration of patisiran monotherapy from an early stage.

[Amyloid ß-related angiitis presenting extensive brain involvement without detection of hemorrhagic lesions: A case report].

In amyloid ß-related angiitis, cortical or subcortical microbleeding or cortical superficial siderosis supports clinical diagnosis. However, here we present a 75-year-old female case of amyloid ß-related angiitis that did not initially show these lesions. The patient developed right homonymous hemianopia and aphasia, and subsequently became comatose. Her brain lesions progressed extensively from the left occipital lobe to the bilateral cerebral hemispheres, with diffused leptomeningeal lesions and scattered DWI high-intensity lesions. After pathological diagnosis, steroid treatment improved her symptoms as well as imaging findings. No hemorrhagic lesions were detected in the T2*-weighted imaging performed before treatment. However, susceptibility-weighted imaging performed after treatment showed a number of lesions with microbleeding. The clinical features of amyloid ß-related angiitis that do not show hemorrhagic lesions at onset should be investigated for rapid therapeutic intervention in the future.

A case of central pontine and extrapontine myelinolysis after surgery for a pituitary tumor.

A 21-year-old woman underwent surgery for a pituitary tumor. On the 11th postoperative day, blood examination revealed severe hyponatremia, with a serum sodium level of 111 mEq/l, and two days later this increased rapidly to 137 mEq/l. On the 20th postoperative day, the patient developed dysarthria and gait disturbance. Head MRI on the 30th postoperative day demonstrated intense high-signal lesions in the pons and bilateral corpus striatum on FLAIR and DWI, and central pontine and extrapontine myelinolysis was diagnosed. The patient's symptoms improved gradually after rehabilitation and antispasticity treatment. It was suggested that the changes in serum sodium levels after pituitary surgery were due to impaired secretion of antidiuretic hormone due to degeneration of nerve terminals in the posterior pituitary. As pituitary surgery may trigger changes in serum sodium leading to myelinolysis, this possibility should always be borne in mind when treating such patients.

Early diagnosis of hepatic intravascular lymphoma: a case report and literature review.

Hepatic intravascular large B-cell lymphoma (IVL) is a rare disease entity that involves invasion into various organs. Due to the aggressive behavior and poor prognosis of the disease and the difficulty in making an early diagnosis, some cases are diagnosed at autopsy. Early suspicion and the use of imaging studies and liver biopsies are key for diagnosing IVL; however, no reports have described the results of imaging studies due to the limited number of cases. We herein report the results of imaging studies of hepatic IVL, including the findings PET-CT, dynamic-CT, EOB-MRI and CEUS. These results may help physicians to make an early diagnosis and improve the prognosis.