Clinical features of familial moyamoya disease

Risk Factors for Preoperative Cerebral Infarction in Infants with Moyamoya Disease

There have been few reports on the risk factors for preoperative cerebral infarction in childhood moyamoya disease (MMD) in infants under 4 years. The aim of this retrospective study is to identify clinical and radiological risk factors for preoperative cerebral infarction in infants under 4 years old with MMD, and the optimal timing for EDAS was also considered. We retrospectively analyzed the risk factors for preoperative cerebral infarction, confirmed by magnetic resonance angiography (MRA), in pediatric patients aged ˂4 years who underwent encephaloduroarteriosynangiosis between April 2005 and July 2022. The clinical and radiological outcomes were determined by two independent reviewers. In addition, potential risk factors for preoperative cerebral infarction, including infarctions at diagnosis and while awaiting surgery, were analyzed using a univariate model and multivariate logistic regression to identify independent predictors of preoperative cerebral infarction. A total of 160 hemispheres from 83 patients aged <4 years with MMD were included in this study. The mean age of all surgical hemispheres at diagnosis was 2.17±0.831 years (range 0.380-3.81 years). In the multivariate logistic regression model, we included all variables with P<0.1 in the univariate analysis. The multivariate logistic regression analysis indicated that preoperative MRA grade (odds ratio [OR], 2.05 [95% confidence interval [CI], 1.3-3.25], P=0. 002), and age at diagnosis (OR, 0.61 [95% CI, 0.4-0.92], P=0. 018) were predictive factors of infarction at diagnosis. The analysis further indicated that the onset of infarction (OR, 0.01 [95% CI, 0-0.08], P<0.001), preoperative MRA grade (OR, 1.7 [95% CI, 1.03-2.8], P=0.037), and duration from diagnosis to surgery (Diag-Op) (OR, 1.25 [95% CI, 1.11-1.41], P<0.001) were predictive factors for infarction while awaiting surgery. Moreover, the regression analysis indicated that family history (OR, 8.88 [95% CI, 0.91-86.83], P=0.06), preoperative MRA grade (OR, 8.72 [95% CI, 3.44-22.07], P<0.001), age at diagnosis (OR, 0.36 [95% CI, 0.14-0.91], P=0.031), and Diag-Op (OR, 1.38 [95% CI, 1.14-1.67], P=0.001) were predictive factors for total infarction. Therefore, during the entire treatment process, careful observation, adequate risk factor management, and optimal operation time are required to prevent preoperative cerebral infarction, particularly in pediatric patients with a family history, higher preoperative MRA grade, duration from diagnosis to operation longer than 3.53 months, and aged ˂3 years at diagnosis.

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.

Genome-wide association study identifies novel susceptibilities to adult moyamoya disease

Genome-wide association study has limited to discover single-nucleotide polymorphisms (SNPs) in several ethnicities. Here, we investigated an initial GWAS to identify genetic modifiers predicting with adult moyamoya disease (MMD) in Koreans. GWAS was performed in 216 patients with MMD and 296 controls using the large-scale Asian-specific Axiom Precision Medicine Research Array. A subsequent fine-mapping analysis was conducted to assess the causal variants associated with adult MMD. A total of 489,966 out of 802,688 SNPs were subjected to quality control analysis. Twenty-one SNPs reached a genome-wide significance threshold (p = 5 × 10-8) after pruning linkage disequilibrium (r2 < 0.8) and mis-clustered SNPs. Among these variants, the 17q25.3 region including TBC1D16, CCDC40, GAA, RNF213, and ENDOV genes was broadly associated with MMD (p = 3.1 × 10-20 to 4.2 × 10-8). Mutations in RNF213 including rs8082521 (Q1133K), rs10782008 (V1195M), rs9913636 (E1272Q), rs8074015 (D1331G), and rs9674961 (S2334N) showed a genome-wide significance (1.9 × 10-8 < p < 4.3 × 10-12) and were also replicated in the East-Asian populations. In subsequent analysis, RNF213 mutations were validated in a fine-mapping outcome (log10BF > 7). Most of the loci associated with MMD including 17q25.3 regions were detected with a statistical power greater than 80%. This study identifies several novel and known variations predicting adult MMD in Koreans. These findings may good biomarkers to evaluate MMD susceptibility and its clinical outcomes.

Identification of a Novel Hypoxia-induced Inflammatory Cell Death Pathway

Hypoxic cancer cells resist many anti-neoplastic therapies and can seed recurrence. We found previously that PTP1B deficiency promotes HER2+ breast cancer cell death in hypoxia by activating RNF213, an ∼600kDa protein containing AAA-ATPase domains and two ubiquitin ligase domains (RING and RZ) that also is implicated in Moyamoya disease (MMD), lipotoxicity, and innate immunity. Here we report that PTP1B and ABL1/2 reciprocally control RNF213 phosphorylation on tyrosine-1275. This phosphorylation promotes RNF213 oligomerization and RZ domain activation. The RZ domain ubiquitylates CYLD/SPATA2, and together with the LUBAC complex, induces their degradation. Decreased CYLD/SPATA2 causes NF-κB activation, which together with hypoxia-induced ER-stress triggers GDSMD-dependent pyroptosis. Mutagenesis experiments show that the RING domain negatively regulates the RZ domain. CYLD -deleted HER2+ cell-derived xenografts phenocopy the effects of PTP1B deficiency, and reconstituting RNF213 knockout lines with RNF213 mutants shows that the RZ domain mediates PTP1B-dependent tumor cell death. Our results identify a novel, potentially targetable PTP1B/RNF213/CYCLD/SPATA pathway critical for controlling inflammatory cell death in hypoxic tumors that could be exploited to target hypoxic tumor cells, potentially turning "cold" tumors "hot". Our findings also reveal new insights into RNF213 regulation, and have potentially important implications for the pathogenesis of MMD, atherosclerosis, and inflammatory and auto-immune disorders.

MMD-associated RNF213 SNPs encode dominant-negative alleles that globally impair ubiquitylation

MMD-associated SNPs of RNF213 encode dominant-negative alleles that globally impair ubiquitylation by RNF213-UBE2D2.

Single-nucleotide polymorphisms (SNPs) in RNF213, which encodes a 591-kD protein with AAA+ ATPase and RING E3 domains, are associated with a rare, autosomal dominant cerebrovascular disorder, moyamoya disease (MMD). MMD-associated SNPs primarily localize to the C-terminal region of RNF213, and some affect conserved residues in the RING domain. Although the autosomal dominant inheritance of MMD could most easily explained by RNF213 gain-of-function, the type of ubiquitylation catalyzed by RNF213 and the effects of MMD-associated SNPs on its E3 ligase activity have remained unclear. We found that RNF213 uses the E2-conjugating enzymes UBE2D2 and UBE2L3 to catalyze distinct ubiquitylation events. RNF213-UBED2 catalyzes K6 and, to a lesser extent, K48-dependent poly-ubiquitylation in vitro, whereas RNF213-UBE2L3 catalyzes K6-, K11-, and K48-dependent poly-ubiquitylation events. MMD-associated SNPs encode proteins with decreased E3 activity, and the most frequent MMD allele, RNF213^R4810K, is a dominant-negative mutant that decreases ubiquitylation globally. By contrast, MMD-associated RNF213 SNPs do not affect ATPase activity. Our results suggest that decreased RNF213 E3 ligase activity is central to MMD pathogenesis.

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.

N. S. Ethnic variation and the relevance of homozygous RNF 213 p.R4810.K variant in the phenotype of Indian Moya moya disease

Background and purpose

Polymorphisms in Ring Finger Protein 213 (RNF 213) gene have been detected to confer genetic susceptibility to Moya moya disease (MMD) in the East Asian population. We investigated the frequency of RNF 213 gene polymorphism and its association with MMD phenotypes in the Indian population.

Materials and methods

A case-control study for RNF 213 polymorphism involving 65 MMD patients, 75 parents, and 120 controls were performed. A total of 21 SNPs were screened, of which 17 SNPs were monomorphic. Allelic and genotypic frequency of all polymorphic SNPs were assessed and its association with MMD phenotypes was evaluated.

Results

The median age of symptom onset was 9 (range 2–17) and 37 years (range 20–58) in paediatric and adult patients respectively. A strong association was observed with RNF 213 rs112735431(p.R4810K) and MMD. Out of 65 patients with MMD, five patients carried the homozygous risk AA genotype. None of the healthy controls carried this homozygous mutation. The mutant allele was detected in MMD patients from Tamil Nadu and North eastern states of India (p = <0.0001). All the patients carrying the mutant allele had an early age of onset (p = <0.0001), higher incidence of bilateral disease (p = <0.002), positive family history (p = 0.03), higher Suzuki angiographic stage (≥3) (p<0.0006) and recurrent neurological events (ischemic strokes and TIAs) (p = <0.009).

Conclusion

The homozygous rs112735431(p.R4810K) variant in RNF 213 variant not only predicts the risk for MMD but can also predict the phenotypic variants.

Moyamoya Disease: A Review of Current Literature

Moyamoya disease (MMD) is an infrequent disease of cerebral vasculature characterized by long-standing and progressive occlusion of large intracranial arteries. It is seen predominantly in the East Asian population. Most of the cases of MMD are sporadic, but there is a small percentage that is familial. The mode of inheritance is reported to be autosomal dominant with incomplete penetrance. Studies show that the susceptibility gene of MMD is located on chromosome 17. The clinical presentation is variable and is influenced by the age and geographic region of the patient. Children mainly present with ischemia-related neurologic episodes whereas MMD in adults can manifest as either an ischemic event or an intracranial hemorrhage (ICH). The gold standard investigation for diagnosis is cerebral angiography which reveals a smoky appearance of arteries at the base of the skull, thus granting the disease its name. The treatment is mostly surgical and includes direct and indirect revascularization procedures, which prevent the recurrence of both ischemic and hemorrhagic strokes. However, combination revascularization procedures are now on the rise due to studies showing better long-term outcomes. The aim of the article is to critically analyze the current literature and updates on various aspects of MMD including, but not limited to, etiology, diagnosis, and treatment.

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

BACKGROUND AND PURPOSE

Genetic factors have been known to play a role in the etiology of moyamoya disease (MMD); however, population-level studies quantifying familial risk estimates are unavailable. We aimed to quantify familial incidence and risk for MMD in first-degree relatives (FDR) in the general population of Korea.

METHODS

By using the Korean National Health Insurance database which has complete population coverage and confirmed FDR information, we constructed a cohort of 21 940 795 study subjects constituting 12 million families with blood-related FDR and followed them for a familial occurrence of MMD from 2002 to 2017. Incidence risk ratios were calculated as MMD incidence in individuals with affected FDR compared with those without affected FDR, according to age, sex, and family relationships.

RESULTS

Among total study subjects, there were 22 459 individuals with affected FDR, of whom 712 familial cases developed MMD with an incidence of 21.8/10⁴ person-years. Overall, the familial risk for MMD was 132-fold higher in individuals with versus without affected FDR. Familial risk (incidence risk ratio; incidence/10⁴ person-years) increased with the degree of genetic relatedness, being highest in individuals with an affected twin (1254.1; 230.0), followed by a sibling (212.4; 35.6), then mother (87.7; 14.4) and father (62.5; 10.4). Remarkably, there was no disease concordance between spouses. The risks were age-dependent and were particularly high in younger age groups. Familial risks were similar in males and females, and the risk of disease transmission was higher in same-sex parent-offspring and sibling pairs.

CONCLUSIONS

Our study indicates that genetic predisposition is the predominant driver in MMD pathogenesis, with minimal contribution of environmental factors. These results could be utilized to direct future genetic studies and clinical risk counseling.

Childhood Moyamoya: Looking Back to the Future

Moyamoya is a chronic, progressive steno-occlusive arteriopathy that typically affects the anterior circulation arteries of the circle of Willis. A network of deep thalamoperforating and lenticulostriate collaterals develop to by-pass the occlusion giving rise to the characteristic angiographic "puff of smoke" appearance. Moyamoya confers a lifelong risk of stroke and neurological demise, with peak age of presentation in childhood ranging between five and 10 years. Moyamoya disease refers to patients who do not have a comorbid condition, whereas moyamoya syndrome refers to patients in whom moyamoya occurs in association with an acquired or inherited disorder such as sickle cell disease, neurofibromatosis type-1 or trisomy 21. The incidence of moyamoya disease and moyamoya syndrome demonstrates geographic and ethnic variation, with a predominance of moyamoya disease in East-Asian populations. Antiplatelet therapy and surgical revascularization procedures are the mainstay of management, as there are no available treatments to slow the progression of the arteriopathy. Future research is required to address the major gaps that remain in our understanding of the pathologic basis, optimal timing for surgery, and determinants of outcome in this high-stroke risk condition of childhood.

Mitochondrial abnormalities related to the dysfunction of circulating endothelial colony-forming cells in moyamoya disease

The authors performed morphological and functional studies of the mitochondria in particular blood cells, i.e., endothelial colony-forming cells (ECFCs), from patients with moyamoya disease. The results indicated that the mitochondria of these ECFCs exhibit morphological and functional abnormalities, which may present new insights into the pathogenesis of moyamoya disease.

The Role of RNF213 4810G>A and 4950G>A Variants in Patients with Moyamoya Disease in Korea

Although a founder variant of RNF213 4810G>A is a major genetic risk factor for moyamoya disease (MMD) in East Asians, the frequency and disease susceptibility of RNF213 variants remain largely unknown. This study investigated the mutation analysis of RNF213 (4448, 4810, 4863, and 4950) between Korean MMD and healthy controls. We performed a polymerase chain reaction-restriction fragment length polymorphism analysis. To identify the association between RNF213 gene polymorphisms and MMD disease, we performed statistical analyses such as multivariable logistic regression and Fisher’s exact test. Genetic data from 117 MMD patients were analyzed and compared with 253 healthy controls. We assessed and compared single nucleotide polymorphisms of RNF213 (4448, 4810, 4863, and 4950) between MMD and control groups. We performed genome-wide association studies to investigate the genetic pathophysiology of MMD. Among the RNF213 variants (4448G>A, 4810G>A, 4863G>A, and 4950G>A), RNF213 4810G>A and 4950G>A variants were more frequent in MMD patients. In a subgroup analysis, the RNF213 4810G>A was more frequent in moyamoya disease, and the comparison with GG+AA genotype was also significantly different in moyamoya patients. These results confirm that RNF213 4810G>A and RNF213 4950G>A were more frequent in MMD patients. We have confirmed that RNF213 4810G>A and 4950G>A are strongly associated with Korean MMD in children and adults as well as for the ischemic and hemorrhagic types.

RNF213 variants in a child with PHACE syndrome and moyamoya vasculopathy

Segmental infantile hemangiomas (IH) can be associated with congenital anomalies in a regional distribution. PHACE refers to large cervicofacial segmental IH in association with congenital anomalies of the aortic arch and medium-sized arteries of the head and neck, as well as structural anomalies of the posterior fossa and eye. A subset of PHACE patients have arterial anomalies that progress to moyamoya vasculopathy (MMV). MMV is defined as stenosis of the supraclinoid segment of the internal carotid arteries and/or their major branches, with subsequent development of a compensatory collateral vessel network. We describe a patient with MMV and segmental IH on the back and lower body who meets diagnostic criteria for PHACE based on a posterior segment eye anomaly and cerebral arterial anomalies. Whole exome sequencing demonstrated two inherited heterozygous variants in RNF213. Variants in RNF213 are associated with increased susceptibility to MMV. Our findings suggest that RNF213 variants may play a role in the development of MMV in patients with hemangioma syndromes associated with congenital cerebral arterial anomalies.

Incidence, clinical features, and treatment of familial moyamoya in pediatric patients: a single-institution series

OBJECTIVE Limited data exist on familial moyamoya in children. The purpose of this study was to characterize presentation and outcomes of pediatric moyamoya patients who have relatives diagnosed with moyamoya. METHODS The authors performed a single-institution retrospective analysis of a case series including all surgically treated children with moyamoya with first- or second-degree relatives with moyamoya. Clinical and radiographic characteristics were analyzed, along with surgical outcomes. RESULTS A total of 537 patients underwent surgery for moyamoya during the study period. Eighteen of those patients (3.4% of the total series) had moyamoya and a family history of moyamoya and were included in this study. Of these 18 patients, 14 were non-twin siblings, and the remaining 4 represented 2 pairs of identical (affected) twins. The presentation was predominantly ischemic (72%), but 4 patients (33%) were asymptomatic when they were found to have moyamoya. Bilateral disease was present in 13 patients (72%). Radiographic stroke prevalence (67%), Suzuki grade (3.3), and angiographic findings were comparable to findings in nonfamilial moyamoya patients. Thirty revascularization procedures were performed, with a 3.3% operative stroke rate per hemisphere and no new strokes in an average follow-up period of 4.5 years. CONCLUSIONS In a North American surgical series, familial moyamoya existed in 3.4% of cases, and was distinguished by manifesting in a broad range of ethnic groups, with a higher proportion of male patients and increased rates of asymptomatic and unilateral disease in comparison to nonfamilial moyamoya. Screening indications remain controversial and the current data are used to suggest guidelines. Surgical therapy is warranted, effective, and durable in these patients, but patients should be carefully selected.

Etiology and pathogenesis of Moyamoya Disease: An update on disease prevalence

Moyamoya disease is a chronic cerebrovascular occlusive disease that is characterized by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The occurrence of Moyamoya disease is related to immune, genetic, and other factors. Though the research of Moyamoya disease has made great strides in the past 60 years, the etiology and pathogenesis are largely unknown. This review will focus on the genetic pathogenic and inflammation factors of Moyamoya disease.

Association between the rs112735431 polymorphism of the RNF213 gene and moyamoya disease: A case-control study and meta-analysis

Ring finger protein 213 (RNF213) gene polymorphisms are thought to be significant in the etiology and pathogenesis of moyamoya disease (MMD). Due to the rarity of MMD patients, their ethnic diversity, and the use of varying methodologies, studies of the association between these polymorphisms and MMD have not been repeatable. This lack of reproducibility affects the strength of the conclusions drawn from their results. We conducted the present case-control study and meta-analysis to provide more precise estimates of the association between the rs112735431 (c.14576G>A) polymorphism and the risk of MMD. A total of 81 MMD patients and 100 healthy controls were enrolled in our case-control study. The RNF213 rs112735431 (c.14576G>A) polymorphism was genotyped using Sanger sequencing after amplification with polymerase chain reaction (PCR). The genetic algorithm (GA) genotype and A allele frequencies of RNF213 rs112735431 (c.14576G>A) (odds ratio, OR=7.10, 95% confidence interval, CI=1.51-33.43, p=0.006; OR=9.37, 95% CI=2.10-41.84, p<0.001, respectively) were significantly higher in the MMD group than those in the control group. In our meta-analysis, we assessed a total of eight case-control studies, including 985 patients and 2335 controls. Pooled ORs indicated a significant association between the presence of the rs112735431 (c.14576G>A) polymorphism and MMD risk (dominant model: OR=74.55, 95% CI=35.86-154.98, p<0.00001). Subgroup analysis based on country and sensitivity analysis verified these results. Our case-control study and meta-analysis both provide evidence of an association between the rs112735431(c.14576G>A) polymorphism in the RNF213 gene and MMD risk.

Moyamoya angiopathy - Is there a Western phenotype?

Moyamoya disease (MMD) is a chronic cerebrovascular disease involving progressive bilateral stenosis of the intracranial segments of the internal carotid arteries. It results in the development of a rich, but friable collateral supply, prone to rupture. The disease is well described in Japanese literature and was originally thought to be a predozminantly Eastern disease. However, the recent literature describes a Western phenotype that may present with a different clinical course. This review aims to describe the variations in the epidemiology of the MMD between Eastern and Western populations, the possible reasons for them and highlight their implications for clinical practise and future research.

Single Nucleotide Polymorphism in Patients with Moyamoya Disease

Moyamoya disease (MMD) is a chronic, progressive, cerebrovascular occlusive disorder that displays various clinical features and results in cerebral infarct or hemorrhagic stroke. Specific genes associated with the disease have not yet been identified, making identification of at-risk patients difficult before clinical manifestation. Familial MMD is not uncommon, with as many as 15% of MMD patients having a family history of the disease, suggesting a genetic etiology. Studies of single nucleotide polymorphisms (SNPs) in MMD have mostly focused on mechanical stress on vessels, endothelium, and the relationship to atherosclerosis. In this review, we discuss SNPs studies targeting the genetic etiology of MMD. Genetic analyses in familial MMD and genome-wide association studies represent promising strategies for elucidating the pathophysiology of this condition. This review also discusses future research directions, not only to offer new insights into the origin of MMD, but also to enhance our understanding of the genetic aspects of MMD. There have been several SNP studies of MMD. Current SNP studies suggest a genetic contribution to MMD, but further reliable and replicable data are needed. A large cohort or family-based design would be important. Modern SNP studies of MMD depend on novel genetic, experimental, and database methods that will hopefully hasten the arrival of a consensus conclusion.

Moyamoya disease and syndromes: from genetics to clinical management

Moyamoya angiopathy is characterized by a progressive stenosis of the terminal portion of the internal carotid arteries and the development of a network of abnormal collateral vessels. This chronic cerebral angiopathy is observed in children and adults. It mainly leads to brain ischemic events in children, and to ischemic and hemorrhagic events in adults. This is a rare condition, with a marked prevalence gradient between Asian countries and Western countries. Two main nosological entities are identified. On the one hand, moyamoya disease corresponds to isolated moyamoya angiopathy, defined as being “idiopathic” according to the Guidelines of the Research Committee on the Pathology and Treatment of Spontaneous Occlusion of the Circle of Willis. This entity is probably multifactorial and polygenic in most patients. On the other hand, moyamoya syndrome is a moyamoya angiopathy associated with an underlying condition and forms a very heterogeneous group with various clinical presentations, various modes of inheritance, and a variable penetrance of the cerebrovascular phenotype. Diagnostic and evaluation techniques rely on magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) conventional angiography, and cerebral hemodynamics measurements. Revascularization surgery can be indicated, with several techniques. Characteristics of genetic moyamoya syndromes are presented, with a focus on recently reported mutations in BRCC3/MTCP1 and GUCY1A3 genes. Identification of the genes involved in moyamoya disease and several monogenic moyamoya syndromes unraveled different pathways involved in the development of this angiopathy. Studying genes and pathways involved in monogenic moyamoya syndromes may help to give insights into pathophysiological models and discover potential candidates for medical treatment strategies.

Nationwide survey on quasi-moyamoya disease in Japan

OBJECTIVES

Moyamoya disease (MMD) is a unique occlusive disease of the bilateral internal carotid arteries with moyamoya vessels. Inherited or acquired disorders and conditions may present in conjunction with MMD. This condition is known as quasi-moyamoya disease. To identify the clinical features of quasi-MMD in Japan, a nationwide survey was conducted.

PATIENTS AND METHODS

A questionnaire was mailed directly to 241 departments that had acknowledged treating quasi-MMD patients in the primary survey. We ascertained the sex, age, family history, clinical manifestation, radiological findings, treatments, course of the disease, and daily activity of the patients.

RESULTS

A total of 114 departments replied to the questionnaire. The data of 108 patients (66 female and 42 male; female to male ratio 1.57) were registered and analyzed. Mean age was 30.6 years old, with a peak in children. Seven patients (7 %) exhibited familial MMD. The initial clinical manifestation was motor weakness, followed by transient ischemic attack and headache. Their imaging study type included ischemic type in 64 patients (63.4 %), bleeding type in seven (6.9 %), and normal in 27 (26.7 %). Stenoocclusive lesion was seen in the internal carotid artery in more than half of the patients. Development of moyamoya vessels was mild in approximately 40 % of the patients. Almost all cases were accompanied by cerebral hypoperfusion. About half of them were unilateral lesion. Vascular reconstruction was employed for the approximately 60 % patients. The prognosis did not change significantly.

CONCLUSION

Clinical features of quasi-MMD were revealed in the nationwide study. In quasi-MMD, unilateral lesion is dominant, and the development of moyamoya vessels and intracranial hemorrhage are less dominant.

Long-term Outcome of Motor Function in a Child with Moyamoya Disease: A Case Report

[Purpose] This observational study provides a retrospective description of changes in motor function of a 10 year old child who suffered from motor weakness caused by Moyamoya disease (MMD) over an approximately 3 year follow-up observation period. [Methods] The child was diagnosed as MMD due to multifocal encephalomalacia in both frontal and parietal cortices. After the ischemic attack, the child received physical therapy the based on stroke rehabilitation, including muscle strengthening exercises, training of functional activity/ADL, and neurodevelopmental treatment. [Results] The child’s MRI showed areas of ischemic infarction in both the frontal and parietal lobes. Steno-occlusive findings for both the anterior cerebral artery and middle cerebral artery were observed on cerebral angiography. Regarding changes of motor function during the three-year follow-up, significant improvements, in the Motricity index, Modified Brunnstrom Classification, manual function test, and functional ambulatory category were observed. [Conclusion] The basic motor function and functional abilities of the child showed improvement with conservative treatment over approximately three years. The functional motor ability of children with MMD may be similar to the recovery progression of pediatric stroke patients, if there is no re-occurrence of ischemia.

Is there a role for treating inflammation in moyamoya disease?: a review of histopathology, genetics, and signaling cascades

Moyamoya disease is a slowly progressing steno-occlusive condition affecting the cerebrovasculature. Affecting the terminal internal carotid arteries (ICA) and there branches, bilaterally, a resulting in a fine vascular network in the base of the brain to allow for compensation of the stenosed vessels. While there is obvious evidence of the involvement of inflammatory proteins in the condition, this has historically not been acknowledged as a causal factor. Here we describe the fundamental histopathology, genetics, and signaling cascades involved in moyamoya and debate whether these factors can be linked as causal factor for the condition or whether they are simply a secondary result of the ischemia described in the condition. A particular focus has been placed on the multitude of signaling cascades linked to the condition as these are viewed as having the greatest therapeutic potential. As such we hope to draw some novel insight into potential diagnostic and therapeutic inflammatory targets in the condition.

Clinical features of familial juvenile cases of moyamoya disease: analysis of patients treated in a single institute over a 28-year period

OBJECT

The authors compared the clinical features between familial and sporadic cases of moyamoya disease (MMD) by retrospectively analyzing data on patients with MMD registered in the database of Tokyo Medical and Dental University over a period of 28 years.

METHODS

In total, 383 patients with hospital records at Tokyo Medical and Dental University from 1980 to 2007 were registered into the database. The data on all of these patients were retrospectively reviewed to clarify the occurrence of familial cases. Clinical features of child or adolescent patients (< 20 years of age) with MMD were compared between familial and sporadic cases in a subgroup of patients who were registered after 1995, initially diagnosed using MR angiography, and assessed using an intelligence scale.

RESULTS

Familial occurrence was observed in 59 patients (15.4%) in 40 pedigrees. The clinical features of juvenile patients were analyzed in 124 patients, 22 (17.7%) of whom had familial histories. In comparison with the sporadic cases, patients with familial histories were significantly younger at onset (4.7 vs 6.6 years old), had significantly more cortical infarction (59.1% vs 25.5%), and had significantly more stenoocclusive lesions in the posterior cerebral artery (45.4% vs 24.5%). The rate of patients with intellectual disturbance (intelligence quotient < 75) was significantly larger in the familial cases (47.4%) than in the sporadic cases (17.8%).

CONCLUSIONS

This survey of the clinical features of familial MMD suggests that patients with familial MMD had a more serious clinical course in childhood than the sporadic MMD cases.

Sex differences in clinical presentation and treatment outcomes in Moyamoya disease

BACKGROUND

Moyamoya (MM) disease is an idiopathic steno-occlusive angiopathy occurring more frequently in females.

OBJECTIVE

To evaluate sex differences in preoperative symptoms and treatment outcomes after revascularization surgery.

METHODS

We analyzed 430 MM disease patients undergoing 717 revascularization procedures spanning 19 years (1991-2010) and compared gender differences in preoperative symptoms and long-term outcomes after surgical revascularization.

RESULTS

A total of 307 female and 123 male patients (ratio, 2.5:1) with a mean age of 31.0 ± 16.7 years and adults-to-children ratio of 2.5:1 underwent 717 revascularization procedures. Female patients were more likely to experience preoperative transient ischemic attacks (odds ratio: 2.1, P = .001) and less likely to receive a diagnosis of unilateral MM disease (odds ratio: 0.6, P = .04). No association was observed between sex and risk of preoperative ischemic or hemorrhagic stroke. There was no difference in neurological outcome because both male and female patients experienced significant improvement in the modified Rankin Scale score after surgery (P < .0001). On Kaplan-Meier survival analysis, 5-year cumulative risk of adverse postoperative events despite successful revascularization was 11.4% in female vs 5.3% in male patients (P = .05). In multivariate Cox proportional hazards analysis, female sex trended toward an association with adverse postoperative events (hazard ratio: 1.9, P = .14).

CONCLUSION

Female patients are more susceptible to the development of preoperative transient ischemic attack and may be at higher risk of adverse postoperative events despite successful revascularization. There is, however, no sex difference in neurological outcome because patients of both sexes experience significant improvement in neurological status with low risk of the development of future ischemic events after surgical revascularization.

Surgical revascularisation for childhood moyamoya

PURPOSE

Children with moyamoya disease/syndrome (MM) have a high rate of recurrent arterial ischaemic stroke (AIS) and associated neurological morbidity; surgical revascularisation (SR) has the potential to prevent this. Here we describe our experience of SR for childhood mm.

METHODS

This study is a retrospective review of case notes and radiology of children with moyamoya who underwent SR at our centre.

RESULTS

Seventy-three children with MM and who had SR were identified, with median age at presentation of 4.75 years (range 0.6-14.5). Children with >1 AIS or transient ischaemic attack (TIA) and who had not infarcted the whole territory of the diseased carotid artery were offered SR, with the primary aim of preventing further AIS. One hundred and thirty-four SR procedures were undertaken: 82 indirect (62.4 %) and 49 (37.6 %) direct procedures with 3 second SR procedures following initial SR. Median age at surgery was 7.3 (1-18.2) years. There was no perioperative mortality. One anticoagulated child developed an intracranial haemorrhage on the fifth post-operative day. Median duration of follow-up was 34 (5-166) months. Three children (4.1 %) had recurrent AIS (one silent) after SR; two with sickle cell disease had intracranial haemorrhage 1.5 and 11 months post-SR. TIAs improved in 42 out of 53 (79.2 %).

CONCLUSION

Our experience of SR for paediatric MM is comparable to other large series. SR is safe, and the rate of recurrent AIS after SR is lower than would be anticipated, on the basis of known natural history of MM. There was no observed difference in outcome of recurrent AIS for direct versus indirect procedures in this series.

Early diagnosis and surgical revascularization for a predictive case of moyamoya disease in a boy born to a moyamoya mother

Among patients with moyamoya disease, familial occurrence is observed in about 20%, suggesting the involvement of genetic factors. In this report, we describe the first predictive case of moyamoya disease in a boy born to a woman who underwent surgical revascularization for moyamoya disease when she was 3 years old. We educated the mother and her family not to miss his initial signs of the disease. His family could easily notice his brief episode of ischemic attack when he was 6 years old. He underwent superficial temporal artery-to-middle cerebral artery anastomosis and indirect bypass on both sides. The postoperative course was uneventful. In conclusion, it is quite important to educate the family not to miss the initial signs of disease in their offspring, at least when they have a genetic background of the disease, because early diagnosis and effective treatment are essential to improve the long-term outcome in pediatric patients.

Moyamoya disease in children

Moyamoya disease is an uncommon cerebrovascular disease characterized by progressive steno-occlusive changes in the terminal internal carotid arteries (ICA) and their main branches, associated with the development of moyamoya vessels. The incidence of the disease is high in east Asia, especially in Japan and Korea. The familial form accounts for 10-15%. Moyamoya disease has two age distribution peaks at around 5 and 40years. Most pediatric patients exhibit transient ischemic attacks or infarction. Headache and involuntary movements are serious symptoms associated with pediatric moyamoya disease. MRI and MR angiography (MRA) are useful and non-invasive methods for diagnosing or monitoring moyamoya disease. Cerebral angiography is still the gold standard for a diagnosis, however, it is not mandatory when MRI and MRA show typical findings of moyamoya disease; steno-occlusive changes at the ends of ICA and an abnormal vascular network in the basal ganglia. Other MRI findings have been reported, including T2 shortening in the white matter, the ivy sign on fluid-attenuated inversion recovery (FLAIR) images, and medullary streaks on FLAIR or enhanced T1-weighted images.

Clinical features and long-term follow-up of quasi-moyamoya disease in children

BACKGROUND

Inherited or acquired disorders and conditions may present in conjunction with moyamoya disease. This condition is known as quasi-moyamoya disease.

METHODS

A retrospective review of 69 moyamoya disease patients treated for the past 20 years identified 7 patients with quasi-moyamoya disease and 5 of them were pediatric patients.

RESULTS

The mean age at initial diagnosis was 6.4 years (range 5-9). Associated disorders were: craniosynostosis, dwarfism with coarctation of aorta, Proteus syndrome, and cranial irradiation for brain tumor. Their clinical type included cerebral ischemia in 3 patients, cerebral bleeding with ischemia in 1 and epilepsy in 1. The 3 patients with cerebral ischemia underwent bypass surgery and their ischemia was improved. One patient died of brain tumor recurrence and the activities of daily living in the remaining patients were affected by mental retardation.

CONCLUSIONS

The clinical course and radiological finding of quasi-moyamoya disease are diverse because of associated disorders, distinguishing definite moyamoya disease.

Movement disorders associated with moyamoya disease: a report of 4 new cases and a review of literatures

The aim of this study was to define the clinical characteristics of patients who developed movement disorders in association with moyamoya disease (MMD). Using PubMed and medical records of our hospital from 1985 to 2008, we searched for patients who developed movement disorders in association with MMD. This study included 38 patients described in previous studies and 4 patients found in the medical records. The onset of movement disorders was thought to be sudden. In 13 patients, the movement disorders were precipitated by hyperventilation or emotional stress. Twenty-seven of the 42 patients developed chorea, 4 patients developed dystonia, and 4 developed a mixture of both. The movement disorders of the remaining 7 patients were described as dyskinesia. A third of the 42 patients developed bilateral movement disorders, and their mean age was younger than that of those with unilateral movement disorders. In 37 of the 42 patients, brain imaging studies showed ischemic lesions, but the remaining 5 patients showed no parenchymal lesions. Cerebral perfusion studies showed hypoperfusion in the basal ganglia and in the cerebral cortical areas. Most patients improved whether they were treated or not. MMD must be included in the differential diagnosis of the sudden onset of dyskinesias, particularly chorea and focal dystonia. Even in patients with no parenchymal lesion in brain imaging studies, cerebral angiography and cerebral blood perfusion studies must be performed, if they develop a sudden onset or recurrent movement disorders preceded by emotional stress or hyperventilation.

Genetics of Moyamoya disease

Moyamoya disease (MMD) is a disease pattern consisting of bilateral stenosis of the intracranial internal carotid arteries (ICA) accompanied by a network of abnormal collateral vessels that bypass the stenosis. Once symptomatic, insufficient cerebral blood flow or rupture of the fragile collaterals may cause stroke or hemorrhage, resulting in severe neurological dysfunction or death. The etiology of MMD is still unknown, although few associations with other diseases and environmental factors have been described. Strong regional differences in epidemiological data, as well as known familial cases, turned the focus to genetics for the insight into the disease's pathogenesis. Thus far, several reports have suggested specific genetic loci and individual genes as predisposing to MMD, but none have demonstrated reproducible results in independent cohorts. Small sample sizes, as well as a likely multifactorial origin, seem to be the most challenging tasks in identifying the disease-causing mechanisms. Once identified, susceptibility genes may allow preventive screening and a possible development of novel therapeutic options.

Moyamoya disease: current concepts and future perspectives

Moyamoya disease is an uncommon cerebrovascular disease that is characterised by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The disease is associated with the development of dilated, fragile collateral vessels at the base of the brain, which are termed moyamoya vessels. The incidence of moyamoya disease is high in east Asia, and familial forms account for about 15% of patients with this disease. Moyamoya disease has several unique clinical features, which include two peaks of age distribution at 5 years and at about 40 years. Most paediatric patients have ischaemic attacks, whereas adult patients can have ischaemic attacks, intracranial bleeding, or both. Extracranial-intracranial arterial bypass, including anastomosis of the superficial temporal artery to the middle cerebral artery and indirect bypass, can help prevent further ischaemic attacks, although the beneficial effect on haemorrhagic stroke is still not clear. In this Review, we summarise the epidemiology, aetiology, clinical features, diagnosis, surgical treatment, and outcomes of moyamoya disease. Recent updates and future perspectives for moyamoya disease will also be discussed.

The influence of genetics on intracranial aneurysm formation and rupture: current knowledge and its possible impact on future treatment

The etiology of intracranial aneurysm formation and rupture remains mostly unknown, but lately several studies have increasingly supported the role of genetic factors. In reports so far, genome-wide linkage studies suggest several susceptibility loci that may contain one or more predisposing genes. Depending on the examined ethnic population, several different non-matching chromosomal regions have been found. Studies of several candidate genes report association with intracranial aneurysms. To date, no single gene has been identified as responsible for intracranial aneurysm formation or rupture. In addition to the well-published environmental factors, such as alcohol intake, hypertension and smoking, only the recent progress in molecular genetics enables us to investigate the possible genetic determinants of this disease. Although a familial predisposition is the strongest risk factor for the development of intracranial aneurysms, the mode of Mendelian inheritance is uncertain in most families. Therefore, multiple genetic susceptibilities in conjunction with the environmental factors are considered to act together in the disease's etiology. Accordingly, researchers performed linkage studies and case-control association studies for the genetic analysis and have identified several genes to be susceptible to intracranial aneurysms. The identification of susceptible genes may lead to the understanding of the mechanism of formation and rupture and possibly lead to the development of a pharmacological therapy. Furthermore, should it be possible to identify a genetic marker associated with an increased risk of formation and rupture of an intracranial aneurysm, the necessity for screening and urgency of treatment could be determined more easily. In this review we summarize the current knowledge of intracranial aneurysm genetics and also discuss the method to detect the causalities. In view of the recent advances made in this field, we also give an outlook on possible future genetically engineered therapies, whose development are well underway.

Smith–Magenis syndrome and moyamoya disease in a patient with del(17)(p11.2p13.1)

Chromosomal rearrangements causing microdeletions and microduplications are a major cause of congenital malformation and mental retardation. Because they are not visible by routine chromosome analysis, high resolution whole-genome technologies are required for the detection and diagnosis of small chromosomal abnormalities. Recently, array-comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MLPA) have been useful tools for the identification and mapping of deletions and duplications at higher resolution and throughput. Smith-Magenis syndrome (SMS) is a multiple congenital anomalies/mental retardation syndrome caused by deletion or mutation of the retinoic acid induced 1 (RAI1) gene and is often associated with a chromosome 17p11.2 deletion. We report here on the clinical and molecular analysis of a 10-year-old girl with SMS and moyamoya disease (occlusion of the circle of Willis). We have employed a combination of aCGH, FISH, and MLPA to characterize an approximately 6.3 Mb deletion spanning chromosome region 17p11.2-p13.1 in this patient, with the proximal breakpoint within the RAI1 gene. Further, investigation of the genomic architecture at the breakpoint intervals of this large deletion documented the presence of palindromic repeat elements that could potentially form recombination substrates leading to unequal crossover.