Moyamoya Syndrome: A Window of Moyamoya Disease

Moyamoya-like vasculopathy develops in association with various systemic diseases and conditions, which is termed moyamoya syndrome. Relatively common diseases and conditions are related to moyamoya syndrome, including neurofibromatosis type 1, Down syndrome, thyroid disease, and cranial irradiation. Moyamoya syndrome shares phenotypical characteristics with idiopathic moyamoya disease. However, they differ in other details, including clinical presentations, natural history, and treatment considerations. The study of moyamoya syndrome can provide clinicians and researchers with valuable knowledge and insight. Although it is infrequently encountered in clinical practice, moyamoya-like vasculopathy can severely complicate outcomes for patients with various underlying diseases when the clinician fails to expect or diagnose moyamoya syndrome development. Furthermore, moyamoya syndrome could be used as a doorway to more enigmatic moyamoya disease in research. More comprehensive survey and investigation are required to uncover the secrets of all the moyamoya-like phenomena.     

Hypomelanosis of Ito and Moyamoya disease

Moyamoya disease is a cerebrovascular disease characterized by stenosis and occlusion of the arteries of the circle of Willis, with abnormal telangiectatic collateral circulation at the base of the brain. An association between moyamoya disease and neurofibromatosis 1, a neurocutanoeus disorder, is well established in the literature. However, its association with other neurocutaneous syndromes is infrequently reported. Hypomelanosis of Ito, another neurocutaneous syndrome, is characterized by macular hypopigmented skin whorls and variable neurologic involvement. Only one case study of an association between hypomelanosis of Ito and moyamoya disease has been reported in the English literature. We report a 17-year-old girl with both hypomelanosis of Ito and angiographic moyamoya disease. She presented with intractable seizures, progressive left hemiparesis, and skin manifestations of hypomelanosis of Ito. Although one might consider a coincidental association, this second case points to an association between the two disorders. Detailed neuroimaging, in particular angiography, should be considered in children with hypomelanosis of Ito and abnormal neurologic findings.     

Renal agenesis and external iliac artery stenosis in an infant with moyamoya disease

We describe a 14-month-old girl who presented with arterial ischemic stroke due to moyamoya disease, unilateral renal agenesis and external iliac artery stenosis. The association of moyamoya disease with renal agenesis and external iliac artery stenosis has not been described before. This report expands the spectrum of moyamoya disease and suggests that moyamoya disease may have an intrauterine onset.     

Elastosis perforans serpiginosa, Down syndrome, and moyamoya disease

A 16-year-old girl with Down syndrome, moyamoya disease, and history of a previous stroke presented with acute onset of left hemiparesis and elastosis perforans serpiginosa. Elastosis perforans serpiginosa in a patient with Down syndrome and moyamoya disease is a novel finding. Development of elastosis perforans serpiginosa in association with progressive vaso-occlusive disease may be a biological marker of progression of moyamoya disease.     

Cerebral oxygenation state in childhood moyamoya disease: a near-infrared spectroscopy study

Near-infrared spectroscopy was used to measure the relative concentration changes of oxygenated hemoglobin (HbO₂), deoxygenated hemoglobin (HbR), and total hemoglobin (t-Hb) before, during, and after hyperventilation in eight patients with childhood moyamoya disease who underwent surgery. The patients were divided into the following two groups: those with and those without re–build-up phenomenon on electroencephalography. All patients except one exhibited decreased concentrations of HbO₂ and t-Hb during hyperventilation and decreased concentrations of HbO₂ and increased concentrations of HbR after hyperventilation. The difference between the hemoglobin concentration during and after hyperventilation was significantly greater in the group with the re–build-up phenomenon than the group without it (P <0.03, Mann-Whitney U test). The patients with the re–build-up phenomenon had lower HbO₂ and higher HbR concentrations after hyperventilation. The concentrations of HbO₂ and HbR reflect an alteration in the oxygenated blood supply and/or oxygen use. Thus, it is strongly suggested that regional cerebral hypoxia and metabolic oxygen disturbances play an important role in the occurrence of the re–build-up phenomenon. Near-infrared spectroscopy is a useful noninvasive method to evaluate the efficacy of surgical treatment in childhood moyamoya disease.     

Moyamoya disease and Down syndrome: case report and review of the literature

We present the case of a 29-year-old woman with Down syndrome who developed bilateral frontal ischemic stroke. Cerebral angiography demonstrated an occlusion of the both supraclinoid internal carotid arteries associated with dilated collateral vessels, consistent with moyamoya disease. We review the clinical and radiological features of moyamoya disease associated with Down syndrome and discuss a few major physiopathologic hypotheses to explain this association.     

Linkage analysis of moyamoya disease on chromosome 6

Genetic factors have been suggested to contribute to the etiology of moyamoya disease. The authors have previously reported an association between moyamoya disease and several alleles for human leukocyte antigens (HLA). To further specify the genetic component of moyamoya disease, a linkage study of moyamoya disease using markers on chromosome 6, where the HLA gene is located, was performed. The 15 microsatellite markers of chromosome 6 were studied in 20 affected sibling pairs. From an identical-by-descent analysis of these markers, an allele with possible linkage to moyamoya disease was identified. Sharing of the allele among affected members in 19 families was investigated, considering the haplotype. The marker, D6S441, might be linked to moyamoya disease. Considering the haplotype, the allele was shared among the affected members in 16 (82%) of the 19 families, but not in two others. In one family, sharing of the allele could not be determined because of low heterozygosity. Further studies are necessary to clarify multiple genetic factors that are definitely linked with moyamoya disease.     

Moyamoya and extracranial vascular involvement: fibromuscular dysplasia? A report of two children

We present two patients with moyamoya syndrome and the unusual involvement of extracranial vessels. The first case illustrates the rare association between moyamoya and primary pulmonary hypertension. In the second patient, moyamoya was complicated by stenoses of vertebral, renal, and mesenteric arteries. In both cases, a systemic intima-proliferative disease, such as fibromuscular dysplasia (FMD), was suspected to be the cause of both intracranial and extracranial arterial disease.     

Early-onset Moyamoya syndrome in a patient with Down syndrome: case report and review of the literature

Moyamoya disease is a chronic occlusive cerebrovascular disorder. It can occur as a primary disease or as a syndrome associated with a variety of conditions. Usually it takes 1 to 2 years to develop a classic moyamoya pattern. We report a 20-month-old girl with Down syndrome and moyamoya syndrome who presented with seizure and hemiparesis. To our knowledge, this is the youngest case reported with moyamoya syndrome and Down syndrome. The prognosis and current treatment of moyamoya syndrome and its relation to Down syndrome are reviewed. There is some reason to speculate that the abnormalities associated with Down syndrome might create a vulnerability for the development of moyamoya syndrome.     

Lipohyalinosis and miliary microaneurysms causing cerebral hemorrhage in a patient with moyamoya. A clinicopathological study

Moyamoya is an intriguing and controversial syndrome. This patient study serves to align the pathophysiology of intracranial hemorrhage in moyamoya with the cerebral vascular disease seen with hypertension, or aging. The historical evidence linking lipohyalinosis and microaneurysms to cerebral hemorrhage is reviewed, the pathogenesis of this angiopathy is discussed, and explanations considered for its association with the vascular pattern of moyamoya. We propose that hemodynamics, genetics or both are among the primary operant etiologic factors.     

On the association of moyamoya disease with Down's syndrome

The occurrence of moyamoya disease in a child with Down's syndrome is reported. Ten previously published instances of this association are briefly reviewed, with comments on its possible significance.     

Moyamoya Syndrome in a Child with Noonan Syndrome

Previous studies have rarely described the association between Noonan syndrome and moyamoya syndrome. Although most affected children with moyamoya exhibit ischemic symptoms, headache is also a frequent symptom. We report the case of a 9-year-old girl with Noonan syndrome and moyamoya syndrome that manifested as recurrent headaches without history of transient ischemic attack. Brain magnetic resonance imaging and magnetic resonance angiography revealed bilateral moyamoya syndrome and mild ventriculomegaly with focal encephalomalacia at right peritrigonal region. Disruption of vascular development during the prenatal stage has been proposed as the cause of cerebrovascular disease in Noonan syndrome. However, genetic factors may also contribute.     

Cerebral hypoxia after hyperventilation causes “re-build-up” phenomenon and TIA in childhood moyamoya disease

Near-infrared spectros-copy was used to monitor the sequential changes in the cerebral oxygenation state during and after hyperventilation in two children with moyamoya disease. Hyperventilation induced the build-up phenomenon and a decrease in the concentration of oxy-hemoglobin ([oxy-Hb]) and total hemoglobin ([t-Hb]). The termination of hyperventilation was followed by partial recovery of [oxy-Hb] and [t-Hb]. Subsequently, however, [oxy-Hb] and [t-Hb] decreased again and cytochrome oxidase was reduced. These impairments of the cerebral hemodynamics and oxygen metabolism were closely associated with the re-build-up phenomenon on EEG and with transient ischemic attacks (TIA). The present study implies that cerebral hypoxia after hyperventilation is closely related to the re-build-up phenomenon and ischemic attacks in children with moyamoya disease.     

A 10-year-old girl with coexistent moyamoya disease and Graves' disease

There are rare reports of young women with moyamoya disease associated with Graves' disease; we are unaware of any previous reports of this association in prepubescent girls. We report a 10-year-old girl who presented with multiple bilateral strokes. Cerebral angiography demonstrated moderate to severe stenosis of her bilateral distal internal carotid arteries and proximal anterior and middle cerebral arteries, which was greater on the right. Thyroid function tests demonstrated suppressed thyroid-stimulating hormone and elevated thyroid hormone levels. Serum antiphospholipid antibody screen demonstrated mild elevations of antiocardiolipin IgG. Possible mechanisms predisposing individuals to concurrent moyamoya and Graves' disease are discussed.     

The moyamoya syndrome associated with irradiation of an optic glioma in children: Report of two cases and review of the literature

We report two cases of the moyamoya syndrome which became clinically apparent after irradiation of an optic glioma during childhood. A summary of 14 cases of this syndrome following irradiation of intracranial tumors is also presented. Nine of these cases were optic gliomas; five were found in children with neurofibromatosis, another disorder that has a strong association with the moyamoya syndrome. The effectiveness of irradiation of optic gliomas in childhood is not definitely established. The possibility of inducing serious vascular disease is a further reason for caution when considering irradiating these tumors.     

De novo appearance of cerebellar cavernous malformation in a patient with moyamoya disease: case report and review of the literature

The authors report a case of cerebellar cavernous malformation associated with moyamoya disease. An adolescent male with moyamoya disease had undergone bilateral direct and indirect extracranial-intracranial anastomosis at 11 years of age, and the course had been uneventful until MRI detected the appearance of a cavernous malformation in the cerebellum 3 years later. The lesion had grown, bled, and caused headache and disturbance of consciousness 2 years after the initial detection. The cavernous malformation was removed surgically and pathologically verified. The patient has recovered without any neurological deficits. This is a quite rare case with cavernous malformation which appeared in a moyamoya disease patient. The association of the two different vascular disorders in a young patient may suggest the existence of some interaction in the pathogenesis of these diseases. Since cavernous malformations with a de novo appearance may grow and become clinically significant, careful observation is necessary.     

Caucasian Familial Moyamoya Syndrome With Rare Multisystemic Malformations

Moyamoya disease is an idiopathic progressive steno-occlusive disorder of the intracranial arteries located at the base of the brain. It is associated with the development of compensatory extensive network of fine collaterals. Moyamoya disease is considered syndromic when certain genetic or acquired disorders such as polycystic kidney disease, neurofibromatosis, or meningitis are also present. Although the genetic contribution in moyamoya is indisputable, its cause and pathogenesis remain under discussion. Herein, we report a rare occurrence of moyamoya syndrome in two European Caucasian siblings in association with unusual multisystemic malformations (polycystic kidney disease in one, and intestinal duplication cyst in the other). The karyotype was normal. No mutation in the RFN213 gene was found, and none of the HLA types linked to moyamoya disease or described in similar familial cases were identified. By describing these multisystemic associations, polycystic kidney disease for the second time, and intestinal malformation for the first time in the literature, our report expands the phenotypic variability of moyamoya syndrome. The coexistence of disparate malformations among close relatives suggests an underlying common genetic background predisposing to structural or physiological abnormalities in different tissues and organs.     

Disappearance of aneurysms associated with moyamoya disease after STA-MCA anastomosis with encephaloduro myosynangiosis

Moyamoya disease is a rare cerebrovascular disease characterized by steno-occlusive vasculopathy affecting the terminal internal carotid arteries. Although the effect of direct arterial bypass on the prevention of recurrent haemorrhage or ischemic events in patients with hemorrhagic moyamoya disease has been demonstrated, disappearance of aneurysms associated with moyamoya disease has rarely been reported. In this study, we present two patients with aneurysms associated with moyamoya disease. After superficial temporal artery to middle cerebral artery anastomosis combined with encephaloduro myosynangiosis, the aneurysms on the moyamoya vessels disappeared, which was confirmed by follow-up angiography.     

单侧烟雾病的最新研究进展

单侧烟雾病是以一侧颈内动脉末端及其主要分支进行性狭窄、闭塞以致脑底出现烟雾状血管的慢性血管病。单侧烟雾病的发病率最高达17．8％,其家族发病率占6．7％。发病年龄的双峰分布、儿童及成人的两种首发症状均与典型烟雾病基本一致,但成人单侧烟雾病患者的脑出血发生率较高,且主要为脑室出血。单侧烟雾病进展勾典型烟雾病的发生率最高可达58．8％。手术治疗可有效地降低缺血性卒中的发生,提高预后,但其适应证有待进一步研究。本文就单侧烟雾病的流行病学、病因学、临床特征、影像学特征、手术及预后等最新研究进展做一综述,增强认识,为诊断及治疗打下基础。     

甲状腺功能亢进与moyamoya综合征的研究进展

与moyamoya病相比,moyamoya综合征尚未形成典型的异常血管网,moyamoya综合征中颅内 动脉狭窄可能是moyamoya病的一个亚型或早期表现,且与moyamoya病存在相同的病理生理学机制。甲 状腺功能亢进相关的moyamoya综合征的病理生理学机制包括自身免疫性破坏、血流动力学异常、动脉 粥样硬化及交感神经兴奋性增加等,诊断和治疗上,应密切关注甲状腺素水平的变化。本文对甲状腺 功能亢进相关的moyamoya综合征的病理生理学机制及临床诊断治疗中应注意的问题做一综述。