RNF213 p.R4810K Variant and Intracranial Arterial Stenosis or Occlusion in Relatives of Patients with Moyamoya Disease

RNF213 variant and autophagic impairment: A pivotal link to endothelial dysfunction in moyamoya disease

Moyamoya disease (MMD) is closely associated with the Ring Finger Protein 213 (RNF213), a susceptibility gene for MMD. However, its biological function remains unclear. We aimed to elucidate the role of RNF213 in the damage incurred by human endothelial cells under oxygen-glucose deprivation (OGD). We analyzed autophagy in peripheral blood mononuclear cells (PBMCs) derived from patients carrying either RNF213 wildtype (WT) or variant (p.R4810K). Subsequently, human umbilical vein endothelial cells (HUVECs) were transfected with RNF213 WT (HUVECWT) or p.R4810K (HUVECR4810K) and exposed to OGD for 2 h. Immunoblotting was used to analyze autophagy marker proteins, and endothelial function was analyzed by tube formation assay. Autophagic vesicles were observed using transmission electron microscopy. Post-OGD exposure, we administered rapamycin and cilostazol as potential autophagy inducers. The RNF213 variant group during post-OGD exposure (vs. pre-OGD) showed autophagy inhibition, increased protein expression of SQSTM1/p62 (p < 0.0001) and LC3-II (p = 0.0039), and impaired endothelial function (p = 0.0252). HUVECR4810K during post-OGD exposure (versus pre-OGD) showed a remarkable increase in autophagic vesicles. Administration of rapamycin and cilostazol notably restored the function of HUVECR4810K and autophagy. Our findings support the pivotal role of autophagy impaired by the RNF213 variant in MMD-induced endothelial cell dysfunction.

RNF213 Mutation Associated with the Progression from Middle Cerebral Artery Steno-Occlusive Disease to Moyamoya Disease

Middle cerebral artery steno-occlusive disease (MCAD) has been recognized as a different clinical entity from moyamoya disease (MMD). Although MCAD can progress to MMD, the extent to which patients actually progress and the risk factors for this progression have not been fully elucidated. We retrospectively reviewed patients with MCAD who underwent RNF213 genotyping. Demographic features, RNF213 p.R4810K mutation, medical history, and longitudinal changes in angiography were analyzed. Sixty patients with 81 affected hemispheres were enrolled. During the follow-up period, 17 patients developed MMD, and the RNF213 p.R4810K mutation was the only factor significantly associated with progression to MMD (odds ratio, 16.1; 95% CI, 2.13-731; P = 0.001). The log-rank test demonstrated that patients with the mutation had a higher risk of progression to MMD (P = 0.007), stenosis progression (P = 0.010), and symptomatic cerebral infarction or hemorrhage (P = 0.026). In Cox regression analysis the p.R4810K mutation remained a significant factor after adjusting for age group (childhood or adult onset) at diagnosis (hazard ratio, 8.42; 95% CI, 1.10-64.4). Hemisphere-based analysis also showed that the mutation was associated with a higher risk of progression to the MMD hemisphere (P = 0.002), stenosis progression (P = 0.005), and cerebral infarction or hemorrhage (P = 0.012). The RNF213 p.R4810K mutation was identified as a risk factor for progression from MCAD to MMD. Genotyping for this mutation may contribute to risk stratification in MCAD.

Amplified Risk of Intracranial Artery Stenosis/Occlusion Associated With RNF213 p.R4810K in Familial Hypercholesterolemia

Background

The RNF213 p.R4810K variant is associated with moyamoya disease in East Asian individuals and increases the risk of developing intracranial major artery stenosis/occlusion (ICASO) that affects anterior circulation. Meanwhile, 0.5% to 2.5% of asymptomatic East Asian individuals also carry this variant. As such, additional factors are likely required to develop ICASO in variant carriers. Familial hypercholesterolemia (FH) is a common genetic disorder in Japan that has a significant associated risk of developing premature coronary atherosclerosis; however, the relationship between ICASO and FH remains unknown.

Objectives

This study aimed to determine if FH facilitates RNF213 p.R4810K carriers to develop ICASO.

Methods

We enrolled patients with FH who had undergone brain magnetic resonance angiography at our hospital from May 2005 to March 2020. The RNF213 p.R4810K variant, and LDLR and PCSK9 mutations were genotyped. ICASO lesions in the brain magnetic resonance angiogram were analyzed.

Results

Six RNF213 p.R4810K variant carriers were identified among 167 patients with FH (LDLR, n = 104; PCSK9, n = 22). Five of the carriers (83.3%) exhibited ICASO in the anterior circulation; a significant difference in ICASO frequency was observed between the variant carriers and noncarriers (P = 0.025). The median number of stenotic or occluded arteries in the anterior circulation was also significantly larger in the variant carriers (3 vs 1, P = 0.01); however, did not differ between patients with FH with LDLR and PCSK9 mutations.

Conclusions

Patients with FH exhibit increased prevalence and severity of ICASO associated with RNF213 p.R4810K. Gene mutations for FH may confer an increased risk of ICASO in RNF213 p.R4810K carriers.

Aplastic or twig-like middle cerebral artery and cardiogenic cerebral embolism mimicking moyamoya disease with RNF213 polymorphism: A case report

Progressive stenosis and occlusion of the bilateral internal carotid artery terminals and circle of Willis are typical features of Moyamoya disease. However, aplastic or twig-like middle cerebral artery (Ap/T-MCA)-wherein the unilateral main trunk of the middle cerebral artery (MCA) is not depicted, and a plexiform arterial network is formed-is similar to the findings of Moyamoya disease. Here, we describe a 78-year-old man who presented with mild right paralysis and aphasia. Magnetic resonance angiography (MRA) at admission did not show the bilateral MCAs. The findings were similar to those of Moyamoya disease, and his symptoms worsened after hospitalization. Endovascular treatment was performed, and the left MCA was completely recanalized. Later, paroxysmal atrial fibrillation was detected, and we finally determined that left MCA occlusion had occurred due to embolism. The right MCA was completely occluded at its origin, indicating an Ap/T-MCA. Embolic occlusion of the unilateral MCA and contralateral Ap/T-MCA made this case resemble Moyamoya disease in the acute stage. Even when chronic occlusion is suspected on MRA in acute cerebral infarction, endovascular treatment should be considered. Additionally, a heterotypic R4810K polymorphism was later found in the RNF213 gene. To our knowledge, this is the second report of Ap/T-MCA with the RNF213 gene polymorphism; however, their association remains unclear and requires further analyses.

RNF213 p.R4810K (c.14429G > A) Variant Determines Anatomical Variations of the Circle of Willis in Cerebrovascular Disease

Introduction

Dysregulation of the RING finger protein 213 (RNF213) gene impairs vascular formation in experimental animal models. In addition, vascular abnormalities in the circle of Willis are associated with cerebrovascular disease. Here, we evaluated the relationship between the East Asian founder variant RNF213 p.R4810K and consequent anatomical variations in the circle of Willis in cerebrovascular disease.

Patients and Methods

The present study is an observational cross-sectional study. It included patients with acute anterior circulation non-cardioembolic stroke admitted to our institution within 7 days of symptom onset or last-known-well from 2011 to 2019, and those who participated in the National Cerebral and Cardiovascular Center Biobank. We compared anatomical variations of the vessels constituting the circle of Willis between RNF213 p.R4810K (c.14429G > A) variant carriers and non-carriers using magnetic resonance angiography and assessed the association between the variants and the presence of the vessels constituting the circle of Willis. Patients with moyamoya disease were excluded.

Results

Four hundred eighty-one patients [146 women (30%); median age 70 years; median baseline National Institutes of Health Stroke Scale score 5] were analyzed. The RNF213 p.R4810K variant carriers (n = 25) were more likely to have both posterior communicating arteries (PComAs) than the variant non-carriers (n = 456) (56% vs. 13%, P < 0.01). Furthermore, variant carriers were less likely to have an anterior communicating artery (AComA) than non-carriers (68% vs. 84%, P = 0.04). In a multivariate logistic regression analysis, the association of RNF213 p.R4810K variant carriers with the presence of both PComAs and the absence of AComA remained significant.

Conclusion

Our findings suggest that the RNF213 p.R4810K variant is an important factor in determining anatomical variations in the circle of Willis.

Mapping Trends in Moyamoya Angiopathy Research: A 10-Year Bibliometric and Visualization-Based Analyses of the Web of Science Core Collection (WoSCC)

Background: Moyamoya angiopathy (MMA), which includes moyamoya disease (MMD) and moyamoya syndrome (MMS), is an uncommon cerebrovascular condition characterized by recurrent stroke. We carried out a bibliometric analysis to examine the development of and research trends in MMA research.

Methods: Studies published between 2010 and 2019 on MMA were retrieved from the Web of Science Core Collection (WoSCC) on August 14, 2020, and bibliometric and visualization-based analyses were performed by using three different scientometric tools: HistCite, VOSviewer, and CiteSpace.

Results: A total of 1,896 publications published in 384 journals by 6,744 authors, 1,641 institutions and 56 countries/regions were included in the analyses. Annual publication outputs increased from 2010 to 2019. The USA, Japan and China were three key contributors to this study field. Capital Medical University, Seoul National University, and Stanford University were three major institutions with larger numbers of publications. Zhang D, World Neurosurgery, Kuroda S, and STROKE were the most prolific author, prolific journal, top co-cited author and top co-cited journal, respectively. The top five keywords during this period were moyamoya disease, revascularization, stroke, children and surgery, while revascularization surgery and RNF213 were the most common frontier topics.

Conclusions: In this study, the research trends of global scientific research on MMA over the past decade were systematically analyzed. The study can provide guidance for scholars who want to understand current trends in research in this area and new research frontiers.

Distribution of Intracranial Major Artery Stenosis/Occlusion According to RNF213 Polymorphisms

Intracranial major artery stenosis/occlusion (ICASO) is the major cause of ischemic stroke. Recent studies have suggested that variants of RNF213, a susceptibility gene for moyamoya disease (MMD), are also related to non-MMD ICASO. Regarding the predominant involvement of steno-occlusion on anterior circulation in MMD, we hypothesized that the ICASO distribution pattern (anterior/posterior) in non-MMD may differ according to RNF213 variants. This study analyzed 1024 consecutive Korean subjects without MMD who underwent computed tomography angiography (CTA) or magnetic resonance angiography (MRA). We evaluated four single nucleotide polymorphisms (SNPs) in the exon region of RNF213: 4448G > A (rs148731719), 4810G > A (rs112735431), 4863G > A (rs760732823), and 4950G > A (rs371441113). Associations between RNF213 variants and anterior/posterior ICASO were examined using multivariate logistic regression analysis. Anterior ICASO was present in 23.0% of study subjects, and posterior ICASO was present in 8.2%. The GA genotype of RNF213 4810G > A (adjusted odds ratio (AOR) [95% confidence interval (CI)], 2.39 [1.14-4.87] compared to GG; p = 0.018) and GA genotype of RNF213 4950G > A (AOR [95% CI], 1.71 [1.11-2.63] compared to GG; p = 0.015) were more frequent in subjects with anterior ICASO. The genotype frequency of RNF213 4863G > A differed significantly according to the presence of posterior ICASO. Further investigations of the functional and biological roles of RNF213 will improve our understanding of the pathomechanisms of ICASO and cerebrovascular disease.

A rare case of pediatric moyamoya disease with reversible white matter lesions in a 3-year-old Chinese girl

Moyamoya disease is a chronic cerebral vascular disease characterized by progressive occlusion of the cerebral arteries and resulting in the development of abnormal collateral circulation. We report a case of moyamoya disease in a 3-year-old Chinese girl with partly reversible white matter lesions. This case indicates that, in pediatric moyamoya disease, white matter lesions may be associated with cerebral ischemia, and they may be reversible after treatment.

Observation of p.R4810K, a Polymorphism of the Mysterin Gene, the Susceptibility Gene for Moyamoya Disease, in Two Female Japanese Diabetic Patients with Familial Partial Lipodystrophy 1

Mysterin, which was recently shown to play an important role in maintaining cellular fat storage, has been identified to be the susceptibility gene for moyamoya disease (MMD). We encountered some female Japanese patients with partial lipodystrophy and MMD-like vascular lesions. This prompted us to examine whether mysterin variants may be present in these patients. We identified a mysterin variant, p.R4810K in two patients with MMD-like vascular lesions, who may fit the category of familial partial lipodystrophy (FPLD) 1. Our cases suggest the possibility that p.R4810K, in addition to atherogenic risk factors, might thus play a role in the development of atherosclerotic lesions in patients with FPLD1 and p.R4810K.

Clinical Features and Surgical Outcomes of Patients With Moyamoya Disease and the Homozygous RNF213 p.R4810K Variant

The ring-finger protein 213 (RNF213) gene is a major susceptibility gene for moyamoya disease. The homozygote of the p.R4810K variant on RNF213 exhibits an early onset age and severe form of moyamoya disease. We report 4 unrelated pediatric moyamoya disease cases with the homozygous p.R4810K variant and the long-term surgical outcomes. Published reports on surgical outcome of moyamoya disease case with the homozygous p.R4810K variant were reviewed. Cerebral angiography revealed classic angiographic findings of moyamoya disease in 7 hemispheres of the 4 children. All patients underwent successful indirect revascularization. Abundant collateral blood flow from the external carotid arteries to the internal carotid arteries was observed in all bypass procedures by angiography. Improvements in symptoms and cerebral blood volume were observed in all patients at long-term follow-up. This report is the first case series in the literature on the surgical management of these patients. These cases highlight the effectiveness of indirect revascularization for moyamoya disease patients with the homozygous p.R4810K variant. Early diagnosis and treatment are crucial to avoid irreversible neurologic deficits in these patients.

Moyamoya angiopathy in PHACE syndrome not associated with RNF213 variants

Moyamoya angiopathy is a rare vasculopathy with stenosis and/or occlusion of bilateral intracranial parts of internal carotid arteries and/or proximal parts of middle and anterior cerebral arteries. PHACE syndrome is characterized by large segmental hemangiomas in the cervical-facial region. Both conditions are known to be associated in rare cases. Recently, it was discussed in the literature that RNF213 variants could be etiologically involved in this association. Here, we describe a childhood case with this rare co-occurrence in which we did not identify any rare RNF213 variant. The clinical and genetic backgrounds are discussed.

RNF213 p.R4810K Polymorphism and the Risk of Moyamoya Disease, Intracranial Major Artery Stenosis/Occlusion, and Quasi-Moyamoya Disease: A Meta-Analysis

BACKGROUND

Accumulating studies have reported that there is an association between the Ring finger protein 213 (RNF213) p.R4810K (rs112735431, c.14576G>A) single nucleotide polymorphism and the predisposition of moyamoya disease (MMD), intracranial major artery stenosis/occlusion (ICASO), quasi-moyamoya disease (quasi-MMD), and other vascular diseases. However, to this day, analyses about this association have remained scarce in the literature. We attempted to conduct a meta-analysis to systematically summarize and clarify the issue.

METHODS

Electronic databases dated up to January 2018 were searched, retrieved, and used. Revman 5.2 software and STATA version 12.0 were used for statistical analysis. The association between RNF213 p.R4810K and MMD, ICASO, and quasi-MMD were assessed by odds ratios and 95% confidence intervals using fixed effects models. Between-study heterogeneity was evaluated by I-squared (I2) statistics and sensitivity analysis was performed by omitting 1 study at a time. A funnel plot and Begg's test were used to assess the potential publication bias.

RESULTS

The outcomes showed a statistically significant association between RNF213 p.R4810K and MMD, ICASO, and quasi-MMD, especially in the dominant model. Apart from the first 2 diseases, no significant association was identified under the recessive, the homozygote, and the heterozygote models in ICASO.

CONCLUSIONS

RNF213 p.R4810K was associated with MMD, ICASO, and quasi-MMD in different genetic models. Subgroup analysis indicated highly significantly higher risk in the Japanese patients. However, further well-designed studies with larger sample size and comprehensive data are needed to confirm our findings and provide a profound conclusion.