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15 result(s) for "Guey, Stéphanie"
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Rare RNF213 variants in the C-terminal region encompassing the RING-finger domain are associated with moyamoya angiopathy in Caucasians
Moyamoya angiopathy (MMA) is a cerebral angiopathy affecting the terminal part of internal carotid arteries. Its prevalence is 10 times higher in Japan and Korea than in Europe. In East Asian countries, moyamoya is strongly associated to the R4810K variant in the RNF213 gene that encodes for a protein containing a RING-finger and two AAA+ domains. This variant has never been detected in Caucasian MMA patients, but several rare RNF213 variants have been reported in Caucasian cases. Using a collapsing test based on exome data from 68 European MMA probands and 573 ethnically matched controls, we showed a significant association between rare missense RNF213 variants and MMA in European patients (odds ratio (OR)=2.24, 95% confidence interval (CI)=(1.19-4.11), P=0.01). Variants specific to cases had higher pathogenicity predictive scores (median of 24.2 in cases versus 9.4 in controls, P=0.029) and preferentially clustered in a C-terminal hotspot encompassing the RING-finger domain of RNF213 (P<10 ). This association was even stronger when restricting the analysis to childhood-onset and familial cases (OR=4.54, 95% CI=(1.80-11.34), P=1.1 × 10 ). All clinically affected relatives who were genotyped were carriers. However, the need for additional factors to develop MMA is strongly suggested by the fact that only 25% of mutation carrier relatives were clinically affected.
The pleiotropy associated with de novo variants in CHD4, CNOT3, and SETD5 extends to moyamoya angiopathy
Moyamoya angiopathy (MMA) is a cerebrovascular disease characterized by occlusion of large arteries, which leads to strokes starting in childhood. Twelve altered genes predispose to MMA but the majority of cases of European descent do not have an identified genetic trigger. Exome sequencing from 39 trios were analyzed. We identified four de novo variants in three genes not previously associated with MMA: CHD4, CNOT3, and SETD5. Identification of additional rare variants in these genes in 158 unrelated MMA probands provided further support that rare pathogenic variants in CHD4 and CNOT3 predispose to MMA. Previous studies identified de novo variants in these genes in children with developmental disorders (DD), intellectual disability, and congenital heart disease. These genes encode proteins involved in chromatin remodeling, and taken together with previously reported genes leading to MMA-like cerebrovascular occlusive disease (YY1AP1, SMARCAL1), implicate disrupted chromatin remodeling as a molecular pathway predisposing to early onset, large artery occlusive cerebrovascular disease. Furthermore, these data expand the spectrum of phenotypic pleiotropy due to alterations of CHD4, CNOT3, and SETD5 beyond DD to later onset disease in the cerebrovascular arteries and emphasize the need to assess clinical complications into adulthood for genes associated with DD.
The Spectrum of Headaches in Moyamoya Angiopathy: From Mechanisms to Management Strategies—A Consensus Review From the NEUROVASC Working Group
Background Moyamoya angiopathy (MMA) is a rare, progressive cerebrovascular disorder characterized by stenosis or occlusion of the terminal internal carotid arteries, leading to the development of fragile collateral vessels. Headache is a common but understudied symptom of MMA, reported in up to 75% of patients. The headache phenotype often mimics migraine or tension‐type headache, although cluster headache‐like episodes have also been described. Aims to summarize current evidence on the clinical characteristics, underlying mechanisms, and treatment strategies for headache in MMA. Materials and Methods A narrative review of the literature was conducted, focusing on the prevalence, phenotype, pathophysiological mechanisms, and therapeutic options for headache in MMA. Results The pathogenesis of headache in MMA remains unclear but is likely multifactorial, involving impaired cerebrovascular autoregulation, microvascular ischemia, and collateral vessel development. No standardized treatment exists for MMA‐related headache. Antiplatelet therapy, particularly aspirin, may offer some benefit, whereas NSAIDs and triptans require caution due to cerebrovascular risks. Emerging therapies such as calcitonin gene‐related peptide (CGRP) inhibitors and Lasmiditan show potential but lack specific data in MMA patients. Surgical revascularization, mainly through direct or combined bypass, is an established intervention for stroke prevention and may also reduce headache burden. However, postoperative outcomes are heterogeneous, with reports of both headache improvement and new‐onset headache. Discussion and Conclusion Headache is a frequent and clinically relevant manifestation of MMA that significantly impacts quality of life. Evidence on optimal management remains scarce, and current strategies are largely empirical. Further studies are needed to clarify pathogenic mechanisms, refine patient selection for surgical interventions, and evaluate pharmacological treatments, including novel agents, to improve clinical outcomes. This article explores headache as a common yet underrecognized symptom of Moyamoya angiopathy (MMA), affecting up to 75% of patients. It reviews the potential pathophysiological mechanisms, including impaired autoregulation and microvascular ischemia, and discusses current and emerging treatment strategies, such as revascularization surgery and CGRP inhibitors. Recognizing and managing headache in MMA is essential to improve patients' daily functioning and overall quality of life.
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.
Biotinidase deficiency mimicking neuromyelitis optica: Initially exhibiting symptoms in adulthood
Background: Children with untreated biotinidase deficiency can experience variable symptoms depending on their age of presentation. Older children and adolescents can exhibit predominant neurological deficits including para- or tetraparesis and vision loss. Methods: We report the first case of delayed-onset biotinidase deficiency in a young adult. Results: A 22-year-old man presented with a disabling extensive myelopathy and bilateral optic neuropathy which mimicked the findings of a (seronegative) neuromyelitis optica. Imaging investigations were characterized by an MRI T2 hyper-intensity involving the spinal cord, the optic nerves, the fornix and the mammillar bodies, together with an increased 18F-FDG uptake on positron emission tomography. He was ultimately shown to have profound biotinidase deficiency due to a novel missense mutation and was partly improved by oral biotin therapy. Conclusion: This individual exemplifies the need to include biotinidase deficiency in the differential diagnosis of patients with extensive myelopathy and/or bilateral optic neuropathy and argues for newborn screening for the disorder.
Cerebral Venous Thrombosis and Nitrous Oxide Intoxication: Report of Two Cases and Review of the Literature
Background Cerebral venous thrombosis (CVT) has various risk factors, including contraception, pregnancy, neoplasia, and thrombophilia. Nitrous oxide (N₂O), historically used as an anesthetic and more recently as a recreational drug, has been associated with neurological complications such as myeloneuropathy and thromboembolic events. Here, we report two cases of CVT associated with N₂O use and provide a review of the literature on this association. Methods We describe two local cases of CVT associated with N2O use and 10 additional cases identified by literature review. Results Among the 12 patients, seven had co‐existing CVT risk factors. Most patients reported chronic N2O use. Hyperhomocysteinemia was reported in nine patients. Management included anticoagulation, vitamin supplementation, cessation of N₂O use, and support for addiction or psychiatric care. The outcome was generally favorable, although one local case experienced CVT recurrence following a relapse in N₂O use. Conclusions These cases highlight an emerging association between CVT and N₂O use. Prompt recognition of this link is critical to recommend cessation of N₂O use, alongside anticoagulation therapy and consideration of vitamin supplementation to prevent complications and recurrence. This manuscript presents two well‐characterized cases of CVT linked to N2O misuse, managed at a French reference center for rare cerebrovascular diseases. To contextualize our findings, we also provide a narrative review of the existing literature, identifying 10 additional cases of CVT associated with N2O use. Our review highlights common clinical features, mechanisms, and management strategies for this rare but significant association.
Border-Zone Cerebral Infarcts Associated with COVID-19 in CADASIL: A Report of 3 Cases and Literature Review
Abstract Introduction: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common inherited cerebral small vessel disease and is a cause of early onset ischemic lacunar stroke. COVID-19 infection may lead, in addition to acute respiratory syndrome, to vascular complications including stroke. Herein, we report three CADASIL patients presenting with cerebral border-zone infarcts concomitant to COVID-19 infection and summarize similar cases previously published in literature. Methods: Clinical and radiological features of the 3 patients were collected and described. A narrative review of literature was performed in PubMed and Google Scholar by the end of 2022 using the “CADASIL” AND “COVID-19” AND “stroke” terms. Results: In our 3 patients, aged 40–58 years, stroke symptoms occurred one to 11 days after the first COVID-19 manifestations. Pulmonary symptoms were mild or absent. One patient presented with hemodynamic failure presumably related to acute cardiomyopathy. Brain magnetic resonance imaging revealed in all cases, ischemic lesions within border-zone areas in both cerebral hemispheres, lesions in the genu of the corpus callosum or in the medium cerebellar peduncles in two cases. The watershed pattern of ischemic lesions was detected in two cases despite any blood pressure drop or severe respiratory dysfunction. Seven CADASIL patients presenting with acute brain infarcts (multiple in 4/7) in context of SARS-CoV-2 infection were identified in literature, despite no fall in blood pressure except for one of them. Conclusion: Our observations, in line with previous reports, further suggest that COVID-19 infection may alter blood flow autoregulation in the deepest cerebral white matter in CADASIL patients. The thrombocytopathy and endotheliopathy developing during COVID-19 infection may participate to the underlying vascular processes.
Biallelic variants in NOS3 and GUCY1A3, the two major genes of the nitric oxide pathway, cause moyamoya cerebral angiopathy
Background Moyamoya angiopathy (MMA) is a rare cerebrovascular condition leading to stroke. Mutations in 15 genes have been identified in Mendelian forms of MMA, but they explain only a very small proportion of cases. Our aim was to investigate the genetic basis of MMA in consanguineous patients having unaffected parents in order to identify genes involved in autosomal recessive MMA. Methods Exome sequencing (ES) was performed in 6 consecutive consanguineous probands having MMA of unknown etiology. Functional consequences of variants were assessed using western blot and protein 3D structure analyses. Results Causative homozygous variants of NOS3 , the gene encoding the endothelial nitric oxide synthase (eNOS), and GUCY1A3 , the gene encoding the alpha1 subunit of the soluble guanylate cyclase (sGC) which is the major nitric oxide (NO) receptor in the vascular wall, were identified in 3 of the 6 probands. One NOS3 variant (c.1502 + 1G > C) involves a splice donor site causing a premature termination codon and leads to a total lack of eNOS in endothelial progenitor cells of the affected proband. The other NOS3 variant (c.1942 T > C) is a missense variant located into the flavodoxine reductase domain; it is predicted to be destabilizing and shown to be associated with a reduction of eNOS expression. The GUCY1A3 missense variant (c.1778G > A), located in the catalytic domain of the sGC, is predicted to disrupt the tridimensional structure of this domain and to lead to a loss of function of the enzyme. Both NOS3 mutated probands suffered from an infant-onset and severe MMA associated with posterior cerebral artery steno-occlusive lesions. The GUCY1A3 mutated proband presented an adult-onset MMA associated with an early-onset arterial hypertension and a stenosis of the superior mesenteric artery. None of the 3 probands had achalasia. Conclusions We show for the first time that biallelic loss of function variants in NOS3 is responsible for MMA and that mutations in NOS3 and GUCY1A3 are causing fifty per cent of MMA in consanguineous patients. These data pinpoint the essential role of the NO pathway in MMA pathophysiology.
Improving methodology of radiosurgery for posterior fossa cavernomas: higher volume, lower dose
Cavernous malformations (CM) of the brain are vascular abnormalities that carry a risk of bleeding, posing significant neurological and life-threatening challenges, particularly in posterior fossa. The efficacy of radiosurgery for cavernomas still remains a matter of debate, largely due to technical and statistical limitations. In this study, we present a series of posterior fossa cavernomas treated using CyberKnife radiosurgery, employing an innovative approach that integrates both technical and statistical advancements. Patients and methods We conducted a prospective series involving 35 posterior fossa cavernomas in 33 patients treated with low-dose radiosurgery protocols (12 Gy in a single fraction or 18 Gy in 3 fractions). Compared to previously published series, our approach targeted a larger treatment volume, encompassing the entire hemosiderin ring surrounding the cavernoma. Radiosurgery was indicated for cases of hemorrhage or progressive neurological deficits in anatomically challenging, nonsurgical areas. The statistical analysis was designed to address the unknown onset time of cavernoma prior to radiosurgery, enabling a more accurate calculation of the hemorrhage incidence rate before treatment. Follow-up evaluations, including clinical assessments and MRI, were conducted at 3-6-9-12-18-24 months and subsequently on an annual basis. Results With a mean follow-up duration of 26 months, exceeding the previously described latency period, and a median [IQR] follow-up of 13 months [8.7-30.4] which represents approximately half the latency period, only one patient experienced a recurrence of hemorrhage, occurring 20 months post-treatment and remaining asymptomatic. No patients exhibited radio-induced parenchymal changes or clinical deterioration following radiosurgery. Conclusions These preliminary results support the strategy of increasing the target volume while reducing the radiation dose for cavernous malformations. We further recommend incorporating sensitivity analyses to evaluate the robustness of results, particularly in the context of uncertainties surrounding the time of onset of cavernomas.
De novo mutations in CBL causing early-onset paediatric moyamoya angiopathy
BackgroundMoyamoya angiopathy (MMA) is characterised by a progressive stenosis of the terminal part of the internal carotid arteries and the development of abnormal collateral deep vessels. Its pathophysiology is unknown. MMA can be the sole manifestation of the disease (moyamoya disease) or be associated with various conditions (moyamoya syndrome) including some Mendelian diseases. We aimed to investigate the genetic basis of moyamoya using a whole exome sequencing (WES) approach conducted in sporadic cases without any overt symptom suggestive of a known Mendelian moyamoya syndrome.MethodsA WES was performed in four unrelated early-onset moyamoya sporadic cases and their parents (trios). Exome data were analysed under dominant de novo, autosomal recessive and X-linked hypotheses. A panel of 17 additional sporadic cases with early-onset moyamoya was available for mutation recurrence analysis.ResultsWe identified two germline de novo mutations in CBL in two out of the four trio probands, two girls presenting with an infancy-onset severe MMA. Both mutations were predicted to alter the ubiquitin ligase activity of the CBL protein that acts as a negative regulator of the RAS pathway. These two germline CBL mutations have previously been described in association with a developmental Noonan-like syndrome and susceptibility to juvenile myelomonocytic leukaemia (JMML). Notably, the two mutated girls never developed JMML and presented only subtle signs of RASopathy that did not lead to evoke this diagnosis during follow-up.ConclusionsThese data suggest that CBL gene screening should be considered in early-onset moyamoya, even in the absence of obvious signs of RASopathy.