Familial Risk for Moyamoya Disease Among First-Degree Relatives, Based on a Population-Based Aggregation Study in Korea

Clinical Course, Therapy, and Long-Term Outcomes of Children With Moyamoya Disease and Posterior Cerebral Artery Involvement

BACKGROUND AND OBJECTIVES

Posterior cerebral artery involvement (PCAi) has been identified as an important factor related to poor prognosis in moyamoya disease (MMD). This study summarized the characteristics of children with MMD and PCAi, clarified the clinical course, identified prognostic predictors, and investigated the long-term effect of encephaloduroarteriosynangiosis for posterior circulation (EDAS-p).

METHODS

We retrospectively reviewed all our pediatric MMD cases with follow-up angiograms from November 2003 to December 2016. PCAi was classified as early-onset at initial diagnosis and delayed-onset after anterior circulation revascularization. Multivariable data including clinical features, radiographic findings, and surgical outcomes were analyzed.

RESULTS

Among 570 children with MMD, 246 (43.2%) had PCAi, with 176 (30.9%) classified as early-onset PCAi. During a median follow-up period of 10 years, 17.8% (70/394) of patients without initial PCAi developed delayed-onset PCAi. The median time to detection of a new PCA lesion was 15.5 (range 7-110) months from initial diagnosis, with a median age of 10.5 (3-22). Younger age at onset, familial occurrence, advanced Suzuki stages, and preoperative infarctions were predictors of delayed-onset PCAi. EDAS-p was performed on 294 hemispheres of 195 patients with PCAi. Stroke-free survival was significantly higher in the EDAS-p group than in the non-EDAS-p group (99.0% vs 90.2%; p < 0.001 [Breslow test]; p = 0.001 [log-rank test]; median follow-up: 101 months).

DISCUSSION

PCAi is not uncommon in children with MMD, underscoring the need for long-term close clinical monitoring, especially in patients with high-risk factors for PCA progression. EDAS-p may be a safe and effective procedure for preventing subsequent stroke in children with MMD and PCAi.

Outcomes of Bypass Surgery in Adult Moyamoya Disease by Onset Type

Importance

Moyamoya disease (MMD) is a rare chronic cerebrovascular disease, and the outcomes of bypass management in adult patients remain controversial.

Objective

To categorize adult MMD based on asymptomatic, ischemic, and hemorrhagic onset and compare the outcomes (death, hemorrhagic stroke [HS], and ischemic stroke [IS]) of bypass surgery (direct or indirect) with those of conservative management.

Design, Setting, and Participants

This retrospective, nationwide, population-based longitudinal cohort study used Korean National Health Insurance Research data to identify adults (aged ≥15 years) with MMD who were diagnosed between January 1, 2008, and December 31, 2020, and followed up until December 31, 2021 (median follow-up, 5.74 [IQR, 2.95-9.42] years). A total of 19 700 participants (3194 with hemorrhagic, 517 with ischemic, and 15 989 with asymptomatic MMD) were included. Data were analyzed from January 2 to April 1, 2023.

Exposures

Bypass surgery and conservative management.

Main Outcomes and Measures

Death constituted the primary outcome; secondary outcomes consisted of HS or IS. Kaplan-Meier survival curve and Cox proportional hazards regression analysis were applied. The propensity score-matching and stratified analyses were performed to control covariate effects.

Results

A total of 19 700 patients (mean [SD] age, 45.43 [14.98] years; 12 766 [64.8%] female) were included. Compared with conservative management, bypass was associated with a reduced risk of death (adjusted hazard ratio [AHR], 0.50 [95% CI, 0.41-0.61]; P < .001) and HS (AHR, 0.36 [0.30-0.40]; P < .001) in hemorrhagic MMD; reduced risk of IS (AHR, 0.55 [95% CI, 0.37-0.81]; P = .002) in ischemic MMD; and reduced risk of death (AHR, 0.74 [95% CI, 0.66-0.84]; P < .001) in asymptomatic MMD. However, bypass was associated with an increased risk of HS (AHR, 1.76 [95% CI, 1.56-2.00]; P < .001) in asymptomatic MMD. Both direct and indirect bypass demonstrated similar effects in hemorrhagic and asymptomatic MMD, except only direct bypass was associated with a reduced risk of IS (AHR, 0.52 [95% CI, 0.33- 0.83]; P = .01) in ischemic MMD. After stratification, bypass was associated with a reduced risk of death in patients younger than 55 years with ischemic (AHR, 0.34 [95% CI, 0.13- 0.88]; P = .03) and asymptomatic (AHR, 0.69 [95% CI, 0.60-0.79]; P < .001) MMD, but an increased risk of HS in patients 55 years or older with ischemic MMD (AHR, 2.13 [95% CI, 1.1-4.16]; P = .03).

Conclusions and Relevance

The findings of this cohort study of bypass outcomes for patients with MMD emphasize the importance of tailoring management strategies in adult patients based on onset types.

A Rare Case of Cardiac Myxoma With Moyamoya Phenomenon: A Disease or Syndrome?

Moyamoya disease (MMD) is a rare, idiopathic, progressive, obstructive, vasculopathy affecting primarily the terminal portions of the intracerebral internal carotid arteries, typically at the base of the brain. It is more commonly seen in people of East Asian descent. The moyamoya phenomenon refers to the characteristic appearance of the tangle of fine blood vessels, also described as a puff of smoke. Moyamoya syndrome (MMS) refers to the constriction-induced chronic brain ischemia that is believed to cause overexpression of proangiogenic factors, creating a fragile network of collateral capillaries. MMS refers to the moyamoya phenomenon in the presence of other congenital or acquired disorders. Intracerebral hemorrhage is the leading cause of death for MMS patients. Overall, the prognosis is variable. Cardiac myxoma can cause embolization of tumor cells, plaques, and thrombus, and recurrent thromboembolism can lead to chronic brain ischemia, which can lead to the development of collaterals. There have been cases reported where the moyamoya phenomenon resolved following myxoma resection. Here, we present the case of a female who had intraventricular bleeding and was diagnosed with MMD. Eighteen months later, she presented with shortness of breath and was diagnosed with cardiac myxoma with multiple valvular regurgitations. The myxoma was surgically removed.

Risk Factors for Massive Cerebral Infarction in Pediatric Patients With Moyamoya Disease

BACKGROUND

To explore the risk factors for preoperative massive cerebral infarction (MCI) in pediatric patients with moyamoya disease (MMD).

METHODS

Pediatric patients with MMD treated between 2017 and 2022 were enrolled. Logistic regression analysis was performed to identify risk factors for MCI among the patients, and a nomogram was constructed to identify potential predictors of MCI. Receiver operating characteristic (ROC) curves and areas under the curves were calculated to determine the effects of different risk factors.

RESULTS

This study included 308 pediatric patients with MMD, including 36 with MCI. The MCI group exhibited an earlier age of onset than the non-MCI group. Significant intergroup differences were observed in familial MMD history, postcirculation involvement, duration from diagnosis to initiation of treatment, Suzuki stage, magnetic resonance angiography (MRA) score, collateral circulation score, and RNF213 p.R4810K variations. Family history, higher MRA score, lower collateral circulation score, and RNF213 p.R4810K variations were substantial risk factors for MCI in pediatric patients with MMD. The nomogram demonstrated excellent discrimination and calibration capabilities. The integrated ROC model, which included all the abovementioned four variables, showed superior diagnostic precision with a sensitivity of 67.86%, specificity of 87.01%, and accuracy of 85.11%.

CONCLUSIONS

This study showed that family history, elevated MRA score, reduced collateral circulation score, and RNF213 p.R4810K variations are risk factors for MCI in pediatric patients with MMD. The synthesized model including these variables demonstrated superior predictive efficacy; thus, it can facilitate early identification of at-risk patients and timely initiation of appropriate interventions.

Paediatric Moyamoya disease: acute presentation with fever and confusion in an 8-year-old: a case report

Introduction and importance

Moyamoya is a chronic vaso-occlusive cerebrovascular disorder which involves internal carotid artery and its proximal branches, forming compensatory Moyamoya vessels. It may manifest with diverse symptoms, but early detection is crucial for a favourable prognosis.

Case presentation

The authors present a case of an 8-year-old child who presented to the emergency with acute onset fever and confusion in speech. Although the symptoms were vague, she was advised for a thorough investigation. MRI of the brain revealed an infarct on the brain that raised suspicion of a vaso-occlussive disorder. Subsequent magnetic resonance angiography and digital subtraction angiography revealed underlying Moyamoya disease.

Clinical discussion

Although the initial diagnosis of Moyamoya disease can be challenging, prompt diagnosis and simple medical measures like single antiplatelet regimens are useful for secondary ischaemic prevention.

Conclusion

This case highlights the essence of considering Moyamoya disease as one of the differentials while dealing with children presenting with subtle cerebrovascular symptoms.

Yield of genetic evaluation in non-syndromic pediatric moyamoya patients

PURPOSE

Few guidelines exist for genetic testing of patients with moyamoya arteriopathy. This study aims to characterize the yield of genetic testing of non-syndromic moyamoya patients given the current pre-test probability.

METHODS

All pediatric moyamoya patients who received revascularization surgery at one institution between 2018 and 2022 were retrospectively reviewed. Patients with previously diagnosed moyamoya syndromes or therapeutic cranial radiation were excluded.

RESULTS

Of 117 patients with moyamoya, 74 non-syndromic patients (44 females, 59%) were eligible. The median age at surgery was 8.1 years. Neurosurgeons referred 18 (24%) patients for neurogenetic evaluation. Eleven (61%) patients subsequently underwent genetic testing. Eight (73%) patients had available testing results. Five (62.5%) of these patients had developmental delay compared to 16 (22%) of the entire cohort. Six (75%) patients who underwent genetic testing were found to have at least one genetic variant. These results led to diagnosis of a new genetic disorder for 1 (12.5%) patient and screening recommendations for 2 (25%) patients. An RNF213 variant in one patient led to recommendations for family member screening and pulmonary hypertension screening. Another patient was diagnosed with CBL disorder and referred for cancer screening. The median age at surgery in patients with clinically actionable findings was 4.6 years compared to 9.2 years in those who were referred for genetic testing. All 3 patients who had an actionable finding had developmental delay.

CONCLUSION

It may be beneficial to refer moyamoya patients under 5 for genetic screening given the high likelihood of discovering actionable mutations.

Clinical and genetic factors associated with contralateral progression in unilateral moyamoya disease: Longitudinal and Cross-Sectional Study

Objective

This study aimed to explore the long-term outcome of unilateral moyamoya disease and predict the clinical and genetic factors associated with contralateral progression in unilateral moyamoya disease.

Methods

We retrospectively recruited unilateral moyamoya disease patients with available genetic data who underwent encephaloduroarteriosynangiosis (EDAS) surgery at our institution from January 2009 to November 2017. Long-term follow-up data, including clinical outcomes, angiographic features, and genetic information, were analyzed.

Results

A total of 83 unilateral moyamoya disease patients with available genetic data were enrolled in our study. The mean duration of clinical follow-up was 7.9 ± 2.0 years. Among all patients, 19 patients demonstrated contralateral progression to bilateral disease. Heterozygous Ring Finger Protein 213 p.R4810K mutations occurred significantly more frequently in unilateral moyamoya disease patients with contralateral progression. Furthermore, patients with contralateral progression typically demonstrated an earlier age of onset than those with non-progressing unilateral moyamoya disease. In the contralateral progression group, posterior circulation involvement was observed in 11 (11/19, 57.9%) patients compared to 12 (12/64, 18.8%) in the non-contralateral progression group (P = 0.001). The time to peak of cerebral perfusion and neurological status showed significant postoperative improvement.

Conclusion

Long-term follow-up revealed that the EDAS procedure might provide benefits for unilateral moyamoya disease patients. Ring Finger Protein 213 p.R4810K mutations, younger age, and posterior circulation involvement might predict the contralateral progression of unilateral moyamoya disease.

Recurrent Cerebral Infarction Due to Moyamoya Disease Complicated With Systemic Lupus Erythematosus: A Case Report and Literature Review

INTRODUCTION

We report a rare case of moyamoya disease caused by an RNF213 mutation, complicated with systemic lupus erythematosus.

CASE REPORT

A 32-year-old woman experienced 4 cerebral ischemia stroke events within 6 months. The main symptom was left limb weakness with blurred vision in the right eye. Results of digital subtraction angiography conducted at another hospital were consistent with moyamoya disease. On genetic testing, we found that the patient carried 2 mutations in the moyamoya disease-related gene RNF213 (p.R4810K, p.T1727M). On the basis of the laboratory immunologic indicators, such as positive antibodies and abnormal immunoglobulin levels and imaging examinations, the patient was finally diagnosed as moyamoya disease complicated with systemic lupus erythematosus. She was treated with aspirin, butylphthalide, urinary kallidinogenase, and sodium methylprednisolone.

CONCLUSIONS

This was a 32-year-old young patient diagnosed with moyamoya disease carrying RNF213 gene mutation and accompanied by lupus with cerebral ischemic event as the first occurrence. The patient's condition was complex; therefore, comprehensive analysis and in-depth consideration were needed to avoid a missed diagnosis and misdiagnosis. When the primary disease cannot be identified, genetic testing can help to clarify the diagnosis of moyamoya disease.

Adult Moyamoya Disease and Syndrome: Current Perspectives and Future Directions: A Scientific Statement From the American Heart Association/American Stroke Association

Adult moyamoya disease and syndrome are rare disorders with significant morbidity and mortality. A writing group of experts was selected to conduct a literature search, summarize the current knowledge on the topic, and provide a road map for future investigation. The document presents an update in the definitions of moyamoya disease and syndrome, modern methods for diagnosis, and updated information on pathophysiology, epidemiology, and both medical and surgical treatment. Despite recent advancements, there are still many unresolved questions about moyamoya disease and syndrome, including lack of unified diagnostic criteria, reliable biomarkers, better understanding of the underlying pathophysiology, and stronger evidence for treatment guidelines. To advance progress in this area, it is crucial to acknowledge the limitations and weaknesses of current studies and explore new approaches, which are outlined in this scientific statement for future research strategies.

Association between statin therapy and the risk of stroke in patients with moyamoya disease: a nationwide cohort study

BACKGROUND AND OBJECTIVE

Knowledge regarding the pharmacological treatment for moyamoya disease (MMD), a chronic and progressive cerebrovascular disease conferring greater stroke risk, is limited. In the present study, whether statin therapy is associated with a reduced risk of stroke in patients with MMD was investigated.

METHODS

This was a retrospective cohort study in which the occurrence of stroke in patients with newly diagnosed MMD was investigated using the nationwide health insurance database in Korea from January 2007 to March 2021. A multivariable Cox proportional hazards regression model was constructed for stroke, in which statin therapy after MMD diagnosis was treated as a time-dependent variable. Adjustment was done for sex, age, presence of comorbidities, concurrent stroke, revascularisation surgery and treatment with antiplatelets.

RESULTS

The present study included 13 373 newly diagnosed patients with MMD; 40.8% had a concurrent stroke at the time of MMD diagnosis. During the mean follow-up of 5.1±3.3 years, 631 patients (4.7%) suffered a stroke event (haemorrhagic stroke: 458 patients, ischaemic stroke: 173 patients). Statin therapy after MMD diagnosis was significantly associated with a reduced risk of stroke (adjusted HR 0.74; 95% CI 0.60 to 0.91, p=0.004). In the secondary outcome analysis, the risk of haemorrhagic stroke (adjusted HR 0.74; 95% CI 0.58 to 0.95, p=0.018) and ischaemic stroke (adjusted HR 0.75; 95% CI 0.52 to 1.08, p=0.124) were reduced with the statin treatment. Taking statins was also associated with a lower risk of all-cause mortality (adjusted HR 0.47; 95% CI 0.33 to 0.67, p<0.001).

CONCLUSION

In patients with MMD, statin therapy was associated with a reduced risk of subsequent stroke. The findings indicate statin treatment may be beneficial for patients with MMD, however the results should be confirmed in randomised controlled trials.

17q25.3 copy number changes: association with neurodevelopmental disorders and cardiac malformation

Copy number variants (CNVs) have been identified as common genomic variants that play a significant role in inter-individual variability. Conversely, rare recurrent CNVs have been found to be causal for many disorders with well-established genotype-phenotype relationships. However, the phenotypic implications of rare non-recurrent CNVs remain poorly understood. Herein, we re-investigated 18,542 cases reported from chromosomal microarray at Greenwood Genetic Center from 2010 to 2022 and identified 15 cases with CNVs involving the 17q25.3 region. We report the detailed clinical features of these subjects, and compare with the cases reported in the literature to determine genotype-phenotype correlations for a subset of genes in this region. The CNVs in the 17q25.3 region were found to be rare events, with a prevalence of 0.08% (15/18542) observed in our cohort. The CNVs were dispersed across the entire 17q25.3 region with variable breakpoints and no smallest region of overlap. The subjects presented with a wide range of clinical features, with neurodevelopmental disorders (autism spectrum disorder, intellectual disability, developmental delay) being the most common features (80%), then expressive language disorder (33%), and finally cardiovascular malformations (26%). The association of CNVs involving the critical gene-rich region of 17q25.3 with neurodevelopmental disorders and cardiac malformation, implicates several genes as plausible drivers for these events.

Prenatal and Infant Exposure to Acid-Suppressive Medications and Risk of Allergic Diseases in Children

Importance

Existing observational data have indicated positive associations of acid-suppressive medication (ASM) use in prenatal and early life with allergic diseases in children; however, no study to date has accounted for confounding by indication or within-familial factors.

Objective

To evaluate the association of prenatal or infant exposure to ASMs with risk of allergic diseases in children.

Design, Setting, and Participants

This nationwide, cohort study included data from South Korea's National Health Insurance Service mother-child-linked database from January 1, 2007, to December 31, 2020. Participants included mother-child pairs of neonates born from April 1, 2008, to December 31, 2019.

Exposures

Prenatal and infant exposure to ASMs (histamine 2 receptor antagonists [H2RAs] and proton pump inhibitors [PPIs]).

Main Outcomes and Measures

Composite and individual outcomes of allergic diseases (asthma, allergic rhinitis, atopic dermatitis, and food allergy) in children (followed up to 13 years of age) were assessed. The ASM-exposed individuals were compared with unexposed individuals in propensity score (PS)-matched and sibling-matched analyses to control for various potential confounders and within-familial factors. Hazard ratios (HRs) with 95% CIs were estimated using Cox proportional hazards regression models.

Results

The study included 4 149 257 mother-child pairs. Prenatal exposure analyses included 808 067 PS-matched pairs (763 755 received H2RAs, 36 529 received PPIs) among women with a mean (SD) age of 31.8 (4.2) years. The PS-matched HR was 1.01 (95% CI, 1.01-1.02) for allergic diseases overall (asthma: HR, 1.02 [95% CI, 1.01-1.03]; allergic rhinitis: HR, 1.02 [95% CI, 1.01-1.02]; atopic dermatitis: HR, 1.02 [95% CI, 1.01-1.02]; food allergy: HR, 1.03 [95% CI, 0.98-1.07]); in sibling-matched analyses, the HRs were similar to those of PS-matched analyses but were not significant (allergic diseases: HR, 1.01; 95% CI, 0.997-1.01). Infant exposure analyses included 84 263 PS-matched pairs (74 188 received H2RAs, 7496 received PPIs). The PS-matched HR was 1.06 (95% CI, 1.05-1.07) for allergic diseases overall (asthma: HR, 1.16 [95% CI, 1.14-1.18]; allergic rhinitis: HR, 1.02 [95% CI, 1.01-1.03]; atopic dermatitis: HR, 1.05 [95% CI, 1.02-1.08]; food allergy: HR, 1.28 [95% CI, 1.10-1.49]); asthma risk (HR, 1.13; 95% CI, 1.09-1.17) remained significantly higher among children exposed to ASMs during infancy in sibling-matched analyses. The findings were similar for H2RAs and PPIs analyzed separately and were robust across all sensitivity analyses.

Conclusions and Relevance

The findings of this cohort study suggest that there is no association between prenatal exposure to ASMs and allergic diseases in offspring. However, infant exposure to ASMs was associated with a higher risk of developing asthma, although the magnitude was more modest than previously reported. Clinicians should carefully weigh the benefits of prescribing ASMs to children, accompanied by subsequent close monitoring for any clinically relevant safety signals.

The Genetic Basis of Moyamoya Disease

Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by progressive spontaneous bilateral occlusion of the intracranial internal cerebral arteries (ICA) and their major branches with compensatory capillary collaterals resembling a “puff of smoke” (Japanese: Moyamoya) on cerebral angiography. These pathological alterations of the vessels are called Moyamoya arteriopathy or vasculopathy and a further distinction is made between primary and secondary MMD. Clinical presentation depends on age and population, with hemorrhage and ischemic infarcts in particular leading to severe neurological dysfunction or even death. Although the diagnostic suspicion can be posed by MRA or CTA, cerebral angiography is mandatory for diagnostic confirmation. Since no therapy to limit the stenotic lesions or the development of a collateral network is available, the only treatment established so far is surgical revascularization. The pathophysiology still remains unknown. Due to the early age of onset, familial cases and the variable incidence rate between different ethnic groups, the focus was put on genetic aspects early on. Several genetic risk loci as well as individual risk genes have been reported; however, few of them could be replicated in independent series. Linkage studies revealed linkage to the 17q25 locus. Multiple studies on the association of SNPs and MMD have been conducted, mainly focussing on the endothelium, smooth muscle cells, cytokines and growth factors. A variant of the RNF213 gene was shown to be strongly associated with MMD with a founder effect in the East Asian population. Although it is unknown how mutations in the RNF213 gene, encoding for a ubiquitously expressed 591 kDa cytosolic protein, lead to clinical features of MMD, RNF213 has been confirmed as a susceptibility gene in several studies with a gene dosage-dependent clinical phenotype, allowing preventive screening and possibly the  development of new therapeutic approaches. This review focuses on the genetic basis of primary MMD only.