Blood vessel organoids generated by base editing and harboring single nucleotide variation in Notch3 effectively recapitulate CADASIL-related pathogenesis

Human blood vessel organoids (hBVOs) offer a promising platform for investigating vascular diseases and identifying therapeutic targets. In this study, we focused on in vitro modeling and therapeutic target finding of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the most common form of hereditary stroke disorder caused by mutations in the NOTCH3 gene. Despite the identification of these mutations, the underlying pathological mechanism is elusive, and effective therapeutic approaches are lacking. CADASIL primarily affects the blood vessels in the brain, leading to ischemic strokes, migraines, and dementia. By employing CRISPR/Cas9 base-editing technology, we generated human induced pluripotent stem cells (hiPSCs) carrying Notch3 mutations. These mutant hiPSCs were differentiated into hBVOs. The NOTCH3 mutated hBVOs exhibited CADASIL-like pathology, characterized by a reduced vessel diameter and degeneration of mural cells. Furthermore, we observed an accumulation of Notch3 extracellular domain (Notch3ECD), increased apoptosis, and cytoskeletal alterations in the NOTCH3 mutant hBVOs. Notably, treatment with ROCK inhibitors partially restored the disconnection between endothelial cells and mural cells in the mutant hBVOs. These findings shed light on the pathogenesis of CADASIL and highlight the potential of hBVOs for studying and developing therapeutic interventions for this debilitating human vascular disorder.

First report of a p.Cys484Tyr Notch3 mutation in a CADASIL patient with acute bilateral multiple subcortical infarcts-case report and brief review

BACKGROUND

CADASIL(Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy)is an inherited small vessel disease caused by mutations in NOTCH3 gene. Although NOTCH3 has numerous hotspots of gene mutations, mutations in exons 9 are rare. The p.C484T gene mutation type associated with it has not been reported in any relevant cases yet. Furthermore, CADASIL patients rarely present with acute bilateral multiple subcortical infarcts.

CASE PRESENTATION

We report the case of a Chinese female patient with CADASIL who experienced "an acute bilateral subcortical infarction" because of"hemodynamic changes and hypercoagulability". In genetic testing, we discovered a new Cys484Tyr mutation in exon 9, which has also been found in the patient's two daughters.

CONCLUSIONS

It is important to note that this discovery not only expands the mutation spectrum of Notch3 mutations in CADASIL patients, but also examines the mechanism behind acute bilateral subcortical infarction in CADASIL patients via case reviews and literature reviews, in order to provide some clinical recommendations for early intervention, diagnosis, and treatment in similar cases in the future.

Impaired cerebral interstitial fluid dynamics in cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy, caused by cysteine-altering variants in NOTCH3, is the most prevalent inherited cerebral small vessel disease. Impaired cerebral interstitial fluid dynamics has been proposed as one of the potential culprits of neurodegeneration and may play a critical role in the initiation and progression of cerebral small vessel disease. In the present study, we aimed to explore the cerebral interstitial fluid dynamics in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy and to evaluate its association with clinical features, imaging biomarkers and disease severity of cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy. Eighty-one participants carrying a cysteine-altering variant in NOTCH3, including 44 symptomatic cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy patients and 37 preclinical carriers, and 21 age- and sex-matched healthy control individuals were recruited. All participants underwent brain MRI studies and neuropsychological evaluations. Cerebral interstitial fluid dynamics was investigated by using the non-invasive diffusion tensor image analysis along the perivascular space method. We found that cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy patients exhibited significantly lower values of diffusion tensor image analysis along the perivascular space index comparing to preclinical carriers and healthy controls. For the 81 subjects carrying NOTCH3 variants, older age and presence of hypertension were independently associated with decreased diffusion tensor image analysis along the perivascular space index. The degree of cerebral interstitial fluid dynamics was strongly related to the severity of cerebral small vessel disease imaging markers, with a positive correlation between diffusion tensor image analysis along the perivascular space index and brain parenchymal fraction and negative correlations between diffusion tensor image analysis along the perivascular space index and total volume of white matter hyperintensity, peak width of skeletonized mean diffusivity, lacune numbers and cerebral microbleed counts. In addition, diffusion tensor image analysis along the perivascular space index was a significant risk factor associated with the development of clinical symptoms of stroke or cognitive dysfunction in individuals carrying NOTCH3 variants. In cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy patients, diffusion tensor image analysis along the perivascular space index was significantly associated with Mini-Mental State Examination scores. Mediation analysis showed that compromised cerebral interstitial fluid dynamics was not only directly associated with cognitive dysfunction but also had an indirect effect on cognition by influencing brain atrophy, white matter disruption, lacunar lesions and cerebral microbleeds. In conclusion, cerebral interstitial fluid dynamics is impaired in cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy and its disruption may play an important role in the pathogenesis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy. Diffusion tensor image analysis along the perivascular space index may serve as a biomarker of disease severity for cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy.

A novel report of Cys1298Gly mutation in exon 24 of NOTCH3 gene in a Chinese family with CADASIL

OBJECTIVES

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is the most common monogenic hereditary small cerebral vessel disease, which is caused by mutation of the neurogenic locus notch homolog protein 3 gene (NOTCH3). The exon 24 encodes EGF-like repeats, variants on this exon are rare. Here, we report a novel heterozygous variant c.3892 T >G (p. Cys1298Gly) on exon 24 of NOTCH3 gene in a 57-year-old Chinese woman.

MATERIALS AND METHODS

We present a patient with clinical manifestations, laboratory examination and imaging reveal suspicion of CADASIL. The family and genetic test and pathological examination were performed.

RESULTS

Magnetic resonance imaging revealed diffuse leukoencephalopathy with hyperintense signals in the bilateral temporal poles, periventricular white matter, centrum semiovale, basal ganglia, frontal and parietal cortex and subcortical areas bilaterally. Molecular Genetic testing identified a heterozygous variant c.3892 T >G (p. Cys1298Gly) on exon 24 of NOTCH3 gene. Her brother and his son were confirmed as subclinical carriers of the variant. The skin biopsy was negative, but the pathologic role of this mutation is predicted by using the DynaMut database and results showed the stability of the NOTCH gene is decreased.

CONCLUSIONS

To the best of our knowledge, this is the second case of exon 24 mutations reported from China and the variant of c.3892 T >G (p. Cys1298Gly) on exon 24 of NOTCH3 has not been reported so far. Our report broadens the mutation spectrum of the NOTCH3 gene in CADASIL.

Recurrent generalized seizures as the prominent manifestation in a patient with CADASIL: a case report and literature review

Background

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited arteriopathy typically caused by mutations in the NOTCH-3 gene. Few detailed descriptions of recurrent generalized seizures in CADASIL has been reported.

Case presentation

This article details a case of recurrent generalized seizures, which eventually be diagnosed as CADASIL with a heterozygous variant, c.1630 C > T (p. Arg544Cys), in exon 11 of the Notch 3 gene. Here, we discussed the possible pathogenesis underlying the epilepsy associated with CADASIL through the brain magnetic resonance imaging changes and the captured epileptiform waves in the electroencephalography during the patient’s follow-up period. Related literatures were also reviewed to discuss the etiology of the epilepsy.

Conclusions

Recurrent generalized seizures may be a presenting neurological manifestation of CADASIL in the absence of other discernible causes. Clinicians should comprehensively seek the possible etiology of patients with recurrent generalized seizures, considering the possible diagnosis of CADASIL.

SARS-CoV-2 infection activating a novel variant of the NOTCH3 gene and subsequently causing development of CADASIL

Introduction

In the following study we describe the diagnostic process and further case analysis of a 30-year-old woman admitted with typical COVID-19 symptoms, who subsequently developed additional symptoms suggesting cerebral autosomal dominant arteriopathy with sub-cortical infarcts and leukoencephalopathy (CADASIL).

Material and methods

Other than the standard diagnostic procedures, whole genome sequencing (WGS) was used, which led to following findings. A new variant of the NOTCH3 gene, which led to CADASIL-like symptoms, was found, and it had been most likely activated by the SARS-CoV-2 infection. This novel variant in NOTCH3 has not been found in existing databases and has never been mentioned in research concerning CADASIL before.

Results

Furthermore, after subjecting the patient's close relatives to WGS it was found that no other examined person demonstrated the same genetic mutation.

Conclusions

It seems therefore that the new variant of NOTCH3 is of de novo origin in the patient's genome. Additionally, the relatively early onset of CADASIL and the unexpectedly severe COVID-19 infection suggest that the two occurred simultaneously: the infection with SARS-CoV-2 accelerated development of CADASIL symptoms and the unusual variant of the NOTCH3 gene contributed to the more severe course of COVID-19.

NOTCH3 mutations in a cohort of Portuguese patients within CADASIL spectrum phenotype

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common inherited cerebral small vessel disease. It is caused by mutations in the NOTCH3 gene, which encodes a membranebound receptor protein with three main distinct functional domains. Thus far, several different NOTCH3 mutations, most of them cysteine altering variants, have been described and although they tend to cluster in certain exons, their distribution varies in different geographically populations. Therefore, in this study, we describe the mutation analysis of NOTCH3 gene in 24 Portuguese families with small vessel disease suspected to have CADASIL from the central region of Portugal. The genetic analysis revealed 15 different heterozygous variants, eight pathogenic cysteine altering variants, six cysteine sparing variants and one nonsense variant, located mainly in the exons 4, 8 and 11. Thus, in our population, the genetic testing should initially be focused on these exons. In addition, the genetic findings broaden the mutational and clinical spectrum of CADASIL related phenotype and provide additional evidences for genetic counseling and clinical management.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) - Still to be Considered in the Presence of Vascular Risk Factors

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a rare hereditary vasculopathy that primarily affects the brain, caused mostly by missense mutations of the NOTCH3 gene which is located on chromosome 19. Clinically, it manifests as transient ischemic attacks and strokes in individuals under the age of 60 years without vascular risk factors. We report a 46-year-old male with a 9 and 3-month history of progressive unilateral lower limb weakness and dysarthria, respectively. He had a history of diabetes mellitus but no hypertension, hyperlipidemia, or smoking history. Both parents had a stroke at the age of 65 years. Neurological examination was significant for moderate dysarthria and reduced right upper limb dexterity. Magnetic resonance imaging (MRI) of the brain revealed extensive white matter disease, lacunar infarcts, and a few microhemorrhages. Electron microscopy of his skin biopsy showed electron-dense deposits of extracellular osmiophilic granular material adjacent to smooth muscle cells. NOTCH3 gene analysis revealed a heterozygous typical mutation in exon 6. He was commenced on aspirin and atorvastatin. Over time, he became more dysarthric and demented. MRI revealed the progression of the white matter disease and a new right subcortical infarct. His aspirin was switched to clopidogrel, and donepezil was added. CADASIL should be considered among younger stroke patients with vascular risk factors, especially in the presence of widespread white matter disease. Genetic counselling may be needed after the diagnosis is made.

Cerebral Microbleed Burdens in Specific Brain Regions Are Associated With Disease Severity of Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Background

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, caused by NOTCH3 mutations, is characterized by recurrent ischemic strokes and progressive cognitive decline. It remains unclear whether cerebral microbleeds (CMBs) can serve as a surrogate marker for disease progression in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. We aimed to investigate the CMB burdens in NOTCH3 mutation carriers at different disease stages and test their associations with cognitive performance.

Methods and Results

Forty‐nine individuals carrying NOTCH3 cysteine‐altering mutations received brain magnetic resonance imaging with T1‐weighted and susceptibility‐weighted images. Whole brain images were segmented into 14 regions using Statistical Parametric Mapping and FreeSurfer software, and semiautomatic methods were used to locate and quantify the number and volume of CMBs. In our study participants, the median of CMB counts was 13, with a wide individual variation (range, 0–286). CMBs were most frequently present in thalamus, followed by temporal lobe. In the whole brain, the CMB counts and CMB volume ratios (ie, CMB volume divided by the volume of corresponding brain region) gradually increased as the disease advanced. CMB counts in the thalamus and temporal and frontal lobes increased more rapidly than other brain regions as disease progressed. There were significant associations between Mini‐Mental State Examination scores and CMB counts in the frontal lobe, temporal lobe, and pons.

Conclusions

CMBs may have an influential role in the clinical manifestations of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. CMB burdens and their distribution in different brain regions may be capable to serve as a disease marker for monitoring the disease severity of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

A large number of cerebral microbleeds in CADASIL patients presenting with recurrent seizures: a case report

Background

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary arteriopathy associated with the NOTCH3 gene. Clinical manifestations include strokes, transient ischaemic events, psychiatric disturbances, dementia, and migraines. We report a case of a Thai man with a severe CADASIL phenotype who presented with recurrent seizures and acute ischaemic stroke and classic vascular risk factors.

Case presentation

A 50-year-old man with a history of mood disorder and progressive cognitive decline for 20 years as well as well-controlled diabetes mellitus and hypertension presented with recurrent generalized seizures and acute right-sided weakness. An MRI of the brain showed acute infarction of the left pons, a large number of cerebral microbleeds throughout the brain and white matter abnormalities without classic anterior temporal lobe lesions. Molecular genetic testing identified a homozygous pathologic variant, c.1672C > T (p. Arg558Cys), in the NOTCH3 gene. The diagnosis of CADASIL was confirmed. His clinical symptoms deteriorated, and he died of tracheobronchitis with secretion obstruction.

Conclusion

This case raises awareness of an uncommon cause of acute ischaemic stroke in patients with classic vascular risk factors and emphasizes the need for a complete evaluation in cases with unexpected clinical presentation or unexpected diagnostic study results.

The role of clinical and neuroimaging features in the diagnosis of CADASIL

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common familial cerebral small vessel disease, caused by NOTCH3 gene mutations. The aim of our study was to identify clinical and neuroradiological features which would be useful in identifying which patients presenting with lacunar stroke and TIA are likely to have CADASIL.

METHODS

Patients with lacunar stroke or TIA were included in the present study. For each patient, demographic and clinical data were collected. MRI images were centrally analysed for the presence of lacunar infarcts, microbleeds, temporal lobe involvement, global atrophy and white matter hyperintensities.

RESULTS

128 patients (mean age 56.3 ± 12.4 years) were included. A NOTCH3 mutation was found in 12.5% of them. A family history of stroke, the presence of dementia and external capsule lesions on MRI were the only features significantly associated with the diagnosis of CADASIL. Although thalamic, temporal pole gliosis and severe white matter hyperintensities were less specific for CADASIL diagnosis, the combination of a number of these factors together with familial history for stroke result in a higher positive predictive value and specificity.

CONCLUSIONS

A careful familial history collection and neuroradiological assessment can identify patients in whom NOTCH3 genetic testing has a higher yield.

Notch3 protein expression in skin fibroblasts from CADASIL patients

AIM

CADASIL is an inherited cerebrovascular disease caused by mutations in the NOTCH3 gene. Notch signaling is involved in a broad spectrum of function, from the cell proliferation to apoptosis. Thus far, because the molecular mechanism underlying the pathological alterations remains unclear and taking into account that fibroblasts contribute to the integrity of the vasculature, our aims was to establish whether fibroblasts, in subjects carrying different NOTCH3 mutations, show abnormalities in the protein expression.

METHODS

We performed the investigation on skin fibroblasts in culture obtained from three CADASIL patients and normal subjects. The patients were genetically characterized, and carried a p.R61W, a p.C174T, and p.R103X, mutation respectively. Notch3 expression was first evaluated on fibroblasts by immunofluorescence analysis, then western blot on cellular extract was utilized to validate the immunofluorescence results.

RESULTS

The Notch3 immunoreactivity was clearly detected along the cellular body and in the cellular nuclei of the control fibroblasts. We observed a marked, statistically significant, reduction of the fluorescence immunoreactivity in the fibroblasts from patient with the classical C174T cysteine mutation and a less pronounced reduction in the other two subject's samples with respect to the normal controls. These data were confirmed by the immunoblot analysis.

CONCLUSIONS

Our results show that the investigated three NOTCH3 mutations are associated with a reduction of the levels of Notch3 expression in vitro. Because the smooth muscle cells appear to be predominantly involved in this cerebrovascular disease, our result, despite the limitation of the sample size examinated, clearly suggest that also fibroblasts, directly involved in making the vascular basal lamina and in maintaining the vascular integrity, may play an important role in the mechanism responsible for the disease.

Potential New Cysteine Sparing Mutation in the NOTCH3 Gene in a Patient with Nonfamilial CADASIL-like Disease

BACKGROUND

Several different mutations have been reported in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). We present a unique case with transversion not involving cysteine on neurogenic locus notch homolog protein 3 gene.

CASE DESCRIPTION

We present a case of 65-year-old woman with new ischemic stroke resulting in right hemiparesis. She has previously suffered minor strokes at age 56, 58, and 60 years and migraine headaches between age 10 and 50 years. Magnetic resonance imaging demonstrated multifocal chronic ischemic infarctions with encephalomalacia in the left posterior parietal, parieto-occipital regions and the pons. An analysis of the protein sequence of notch 3 gene did not demonstrate any alterations characteristics of CADASIL disease. There was a deoxyribonucleic acid variant with transversion of alanine with tyrosine and change of histidine with leucine on notch 3 gene. None of the family members had any clinical manifestations suggestive of CADASIL.

CONCLUSION

We report the first report of deoxyribonucleic acid variation in notch 3 gene associated with clinical features of CADASIL without any familial component.

The spectrum of infantile myofibromatosis includes both non-penetrance and adult recurrence

Infantile myofibromatosis is characterized by benign myofibroblastic tumors within skin, muscle, bone or viscera which have a characteristic staining pattern on immunohistochemistry. The condition typically presents in infancy and the tumors often disappear by the third year of life. Mutations in the PDGFRB gene and NOTCH3 genes have been identified in familial forms of the condition. We present two families with molecularly confirmed germline mutations in the PDGFRB gene, one demonstrating a phenotype ranging from complete non-penetrance to neonatal lethality; and the other illustrating adult recurrence of the tumors.

CADASIL presenting with spontaneous intracerebral hemorrhage: report of a case and description of the first family in Northern Greece

INTRODUCTION

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), the most common inherited cause of stroke and dementia in adults, has been described in six Greek families. Common presenting manifestations include migraine with aura, brain ischemia, mood disorders and cognitive decline. Spontaneous intracerebral hemorrhage (SICH) rarely occurs in CADASIL and only exceptionally as the first clinical manifestation.

CASE DESCRIPTION

We have previously reported the sixth Greek family with CADASIL and in particular, two brothers in whom the genetic testing documented a classic mutation of the NOTCH3 gene (Arg169Cys). In this report, we describe the 30-year-old son of the second brother, who suffered a thalamic SICH as the presenting manifestation of CADASIL, in the absence of arterial hypertension or antiplatelet drug use.

CONCLUSION

Patients with acute subcortical infarcts, leukoencephalopathy, a history of migraine, mood disorders, and dementia, should always raise the suspicion of CADASIL. However, a SICH, even in the absence of classical risk factors for hemorrhage, is possible and should not exclude the diagnosis of CADACIL. Hippokratia 2016, 20(1): 76-79.

The genetic spectrum and the evaluation of CADASIL screening scale in Chinese patients with NOTCH3 mutations

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small artery disease caused by NOTCH3 gene mutation. Here we report clinical, pathological and genetic profiles of 29 newly-diagnosed CADASIL patients, evaluation of the CADASIL scale in Chinese CADASIL patients, and reanalysis of all reported mainland Chinese patients with identified NOTCH3 gene mutation. We found two novel mutations (p.C134G and p.C291Y) and 13 reported NOTCH3 mutations in the newly-diagnosed group. CADASIL scale score was less than the cutoff score in 19 of 53 Chinese patients with NOTCH3 mutation, generating only a sensitivity of 64.1%. At the time of study, the total number of genetically confirmed CADASIL cases reached 158 from 97 unrelated mainland Chinese families, with 9/97 (9.3%) sporadic patients. The NOTCH3 gene mutation profile showed 43 mutations, with hotspots in exon 4, followed by exon 3. The considerable variability in onset age and CADASIL scale score in patients carrying the same NOTCH3 missense mutation suggested no obvious phenotype-genotype correlation. In conclusion, we report two novel mutations which expand the NOTCH3 mutational spectrum. Exons 4 and 3 are hotspots in mainland Chinese patients with NOTCH3 mutation. The low sensitivity of CADASIL scale in our patients group indicated that the CADASIL scale should be refined according to the clinical characteristics of Chinese CADASIL patients when used in Chinese populations.

Two novel mutations in NOTCH3 gene causes cerebral autosomal dominant arteriopathy with subcritical infarct and leucoencephalopathy in two Chinese families

OBJECTIVE

To investigate the genetic pathogenic causes of cerebral autosomal dominant arteriopathy with subcritical infarct and leucoencephalopathy (CADASIL) in two Chinese families, to provide the molecular basis for genetic counseling and antenatal diagnosis.

METHODS

The genetic mutation of gene NOTCH3 of propositus and family members was analyzed in these two CADASIL families by polymerase chain reaction and DNA sequencing technology directly. At the same time, the NOTCH3 gene mutation point of 100 healthy collators was detected, to explicit the pathogenic mutation by function prediction with Polyphen-2 and SIFT.

RESULTS

Both propositus of the two families and patients with symptom were all accorded with the clinical features of CADASIL. It was shown by DNA sequencing that the 19(th) exon [c. 3043 T > A (p.Cys1015Ser)] in gene NOTCH3 of propositus, 2 patients (II3, III7), and a presymptomatic patient (IV1) in Family I all had heterozygosity missense mutation; and the 3(rd) exon [c.316T > G, p. (Cys106Gly)] in gene NOTCH3 of the propositus, a patient (IV3) and two presymptomatic patients (IV5, 6) in Family II all had heterozygosity missense mutation; and no mutations were detected in the 100 healthy collators. It was indicated by analyzing the function prediction that the mutation of [c. 3043 T > A (p.Cys1015Ser)] and [c.316T > G, p. (Cys106Gly)] may both influence encoding protein in NOTCH3. By analysis of the conservatism of mutation point in each species, these two basic groups were highly conserved.

CONCLUSION

The heterozygosity missense mutation of 19(th) exon [c. 3043 T > A (p.Cys1015Ser)] and the 3(rd) exon [c.316T > G, p. (Cys106Gly)] in NOTCH3 gene are the new pathogenic mutations of CADASIL, and enriches the mutation spectrum of NOTCH3 gene.

New mutations in the Notch3 gene in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL)

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a cerebrovascular small-vessel disease caused by stereotyped mutations in the Notch3 gene altering the number of cysteine residues.

METHODS

We directly sequenced exons 2-23 of the Notch3 gene in 30 unrelated Russian patients with clinical/neuroimaging picture suggestive of CADASIL. To confirm the pathogenicity of new nucleotide variants, we used the standard bioinformatics tools and screened 200 ethnically matched individuals as controls.

RESULTS

We identified 16 different point mutations in the Notch3 gene in 18 unrelated patients, including 4 new missense mutations (C194G, V252M, C338F, and C484G). All but two mutations affected the cysteine residue. The non-cysteine change V322M was shown to be associated with CADASIL-specific deposits of granular osmiophilic material in the vascular smooth-muscle cells, which confirmed the pathogenicity of this Notch3 variant. Two patients were shown to be compound-heterozygotes carrying two pathogenic Notch3 mutations. The disease was characterized by marked clinical variability, without evident phenotype-genotype correlations.

CONCLUSIONS

In our sample, 60% of Russian patients with 'clinically suspected' CADASIL received the definitive molecularly proven diagnosis. Careful assessment of genealogical, clinical, and neuroimaging data in patients with lacunar stroke can help selecting patients with a high probability of finding mutations on genetic screening.

Clinical, familial, and neuroimaging features of CADASIL-like patients

OBJECTIVES

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small vessel disease caused by NOTCH3 mutations. There are no clinical and neuroimaging findings pathognomonic of the disease. The aim of this paper was to provide a description of a group of NOTCH3-negative patients with a phenotype closely resembling that of CADASIL.

MATERIALS AND METHODS

We performed NOTCH3 analysis (exons 2-23) in 117 probands because of a clinician's suspicion of CADASIL. The CADASIL scale, a recently developed tool that allows to better select patients for NOTCH3 analysis, was retrospectively applied to NOTCH3-negative patients; the patient subgroup that scored higher than the screening cutoff for CADASIL was defined as CADASIL-like.

RESULTS

Thirty-four CADASIL-like patients (mean age at onset 57.8 years [52.1-63.4], 50% males) were identified. Compared with 25 patients with CADASIL for clinical, familial, and neuroimaging features, only the following variables were significantly (α level <0.05) different in frequency between patients with CADASIL and CADASIL-like patients: a positive family history for stroke at age ≤ 60 years, more frequent in patients with CADASIL, and hypertension, more frequent in CADASIL-like patients.

CONCLUSIONS

Our experience highlights the growing number of patients presenting with a high suspicion of a cerebral small vessel disease with an autosomal dominant pattern of inheritance and a phenotype closely similar to that of CADASIL but without NOTCH3 mutations. This group remains to be characterized from the genetic point of view. The role of other genes or NOTCH3 alterations on exons other than 2-23 or introns has to be further assessed.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: Phenotypic and mutational spectrum in patients from mainland China

AIMS

To analyze the NOTCH3 gene mutations in patients from mainland China clinically suspected to have cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and evaluate large intracranial arteries in CADASIL patients.

METHODS

We performed clinical, neuroimaging and NOTCH3 gene (exons 2-23) examinations in 47 subjects from 34 families. Large intracranial arteries were assessed using magnetic resonance angiography (MRA) in 19 cases with NOTCH3 gene variants.

RESULTS

Screening of exons 3 and 4 identified six different known mutations in eight families and two novel mutations in two families. Further screening of the remaining exons identified p.R1175W, a variant of unknown significance. The incidence of NOTCH3 mutations was 29.4% (10/34). Five cases with NOTCH3 mutations showed intracranial atherosclerosis. One patient developed cerebral infarction due to left middle cerebral artery occlusion (M2 segment).

CONCLUSIONS

The NOTCH3 mutation spectrum in our group was diverse and consistent with those in Caucasians but differed from those in Korea and Taiwan. The screening strategy used in Caucasian populations can be applied to mainland Chinese patients. Atherosclerosis of the large intracranial arteries involvement does not exclude CADASIL diagnosis.