Population-specific spectrum of NOTCH3 mutations, MRI features and founder effect of CADASIL in Chinese

Expanding the Neurological Phenotype of Anderson-Fabry Disease: Proof of Concept for an Extrapyramidal Neurodegenerative Pattern and Comparison with Monogenic Vascular Parkinsonism

Anderson-Fabry disease (AFD) is a genetic sphingolipidosis involving virtually the entire body. Among its manifestation, the involvement of the central and peripheral nervous system is frequent. In recent decades, it has become evident that, besides cerebrovascular damage, a pure neuronal phenotype of AFD exists in the central nervous system, which is supported by clinical, pathological, and neuroimaging data. This neurodegenerative phenotype is often clinically characterized by an extrapyramidal component similar to the one seen in prodromal Parkinson's disease (PD). We analyzed the biological, clinical pathological, and neuroimaging data supporting this phenotype recently proposed in the literature. Moreover, we compared the neurodegenerative PD phenotype of AFD with a classical monogenic vascular disease responsible for vascular parkinsonism and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). A substantial difference in the clinical and neuroimaging features of neurodegenerative and vascular parkinsonism phenotypes emerged, with AFD being potentially responsible for both forms of the extrapyramidal involvement, and CADASIL mainly associated with the vascular subtype. The available studies share some limitations regarding both patients' information and neurological and genetic investigations. Further studies are needed to clarify the potential association between AFD and extrapyramidal manifestations.

Most common NOTCH3 mutations causing CADASIL or CADASIL-like cerebral small vessel disease: A systematic review

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a monogenic disorder caused by mutations in the NOTCH3 gene. The main aim of our survey was to determine if there is an association between phenotypes and genotypes across the most common NOTCH3 mutations found in CADASIL patients. We systematically searched clinical studies and genomic databases from 1996 to 2023 to first identify the most common mutations responsible for CADASIL. We found the six most common NOTCH3 missense mutations globally were the p.R75P, p.R133C, p.R141C, p.R169C, p.R182C, and p.R544C, of which p.R133C was described to occur most often. Focusing on studies with comprehensive clinical records, our analysis further suggested that the p.R75P, p.R141C, p.R182C and p.R544C genotypes were highly congruent with the presence of white matter hyperintensities on magnetic resonance imaging (MRI), which was the most common phenotypic characteristic across all four mutations. We found the p.R141C mutation was associated with increased severity of disease. We also found the average age of onset in p.R544C carriers was more than a decade later compared to the p.R141C carriers. However, statistical analysis showed there were no overall differences between the phenotypic characteristics of the two common mutations, p.R141C and p.R544C. Geographically, China and Japan were the only two countries to report all the four common mutations vis a vis p.R75P, p.R141C, p.R182C and p.R544C. There is a possibility that this is due to a combination of a founder effect, but there also could be sampling biases.

Prevalence, clinical characteristics, and risk factors of intracerebral haemorrhage in CADASIL: a case series and systematic review

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of stroke and is characterised by early onset stroke and dementia. Most strokes are lacunar ischaemic strokes, but intracerebral haemorrhage (ICH) has also been reported, although there are limited published data on its frequency and characteristics.

METHODS

A retrospective review of a prospectively recruited CADASIL register from the British National Referral clinic was performed to identify acute ICH cases and their characteristics. In addition, a systematic review of ICH in CADASIL was performed. MEDLINE (Pubmed), Embase, and Web of Science were searched for articles published from inception until 31/05/2023.

RESULTS

Ten cases of ICH were identified from the National clinic register of 516 symptomatic patients, giving an estimated point prevalence of 1.9%. An additional 119 cases were identified from the systematic review, comprising 129 cases and 142 ICH events in total. Including all identified cases, the mean age at onset of ICH was 56.6 ± 15.7 (SD) years, and 74 (57.4%) were male. ICH was the first manifestation of the disease in 32 patients (38.1%), and ICH recurrence occurred in 16 (12.4%). Most ICHs were subcortical, with the thalamus, 58 (40.8%), and basal ganglia, 34 (23.9%), being the commonest sites. Anticoagulation, but not antiplatelet agents, was associated with an increased risk of ICH (20.0% vs. 1.9%, p = 0.006).

CONCLUSIONS

ICH is a relatively rare manifestation of CADASIL, occurring in about 2% of symptomatic cases. Most of the haemorrhages occurred in the subcortical regions.

Monogenic causes of cerebral small vessel disease and stroke

Cerebral small vessel disease (cSVDs) account for 25% of stroke and are a frequent cause of cognitive or motor disability in adults. In a small number of patients, cSVDs result from monogenic diseases, the most frequent being cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). An early disease onset, a suggestive family history, and a low vascular risk profile contrasting with a high load of cSVD imaging markers represent red flags that must trigger molecular screening. To date, a dozen of genes is involved in Mendelian cSVDs, most of them are responsible for autosomal dominant conditions of variable penetrance. Some of these mendelian cSVDs (CADASIL, HTRA1-related cSVD, pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), cathepsin-A related arteriopathy with strokes and leukoencephalopathy (CARASAL), and cSVD related to LAMB1 mutations) are causing ischemic stroke. Others (COL4A1/COL4A2-related angiopathy and hereditary cerebral amyloid angiopathy) preferentially lead to intracerebral hemorrhages. The clinical features of different Mendelian cSVDs can overlap. Therefore, the current approach is based on simultaneous screening of all genes involved in these conditions through a panel-targeted sequencing gene or exome sequencing. Nevertheless, a pathogenic variant is identified in less than 15% of patients with a suspected genetic cerebrovascular disease, suggesting that many additional genes remain to be identified.

Headache and NOTCH3 Gene Variants in Patients with CADASIL

Autosomal dominant cerebral arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited vascular disease characterized by recurrent strokes, cognitive impairment, psychiatric symptoms, apathy, and migraine. Approximately 40% of patients with CADASIL experience migraine with aura (MA). In addition to MA, CADASIL patients are described in the literature as having migraine without aura (MO) and other types of headaches. Mutations in the NOTCH3 gene cause CADASIL. This study investigated NOTCH3 genetic variants in CADASIL patients and their potential association with headache types. Genetic tests were performed on 30 patients with CADASIL (20 women aged 43.6 ± 11.5 and 10 men aged 39.6 ± 15.8). PCR-HRM and sequencing methods were used in the genetic study. We described three variants as pathogenic/likely pathogenic (p.Tyr189Cys, p.Arg153Cys, p.Cys144Arg) and two benign variants (p.Ala202=, p.Thr101=) in the NOTCH3 gene and also presented the NOTCH3 gene variant (chr19:15192258 G>T), which has not been previously described in the literature. Patients with pathogenic/likely pathogenic variants had similar headache courses. People with benign variants showed a more diverse clinical picture. It seems that different NOTCH3 variants may contribute to the differential presentation of a CADASIL headache, highlighting the diagnostic and prognostic value of headache characteristics in this disease.

A case of recurrent intracranial hemorrhage in CADASIL caused by NOTCH3 c.1759C>T heterozygous mutation

BACKGROUND

Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a cerebrovascular disease that is closely related to the NOTCH3 gene. Recurrent ischemic stroke, progressive cognitive dysfunction, and mental symptoms are the main clinical manifestations, whereas symptomatic intracranial hemorrhage is rare.

METHODS

We detected a heterozygous mutation of c.1759C>T in exon 11 of the NOTCH3 gene that caused recurrent intracranial hemorrhage in CADASIL.

RESULTS

Second-generation sequencing of a sample of the patient's genome revealed a heterozygous mutation of c.1759C>T in exon 11 of NOTCH3, which resulted in amino acid changes (p.R587C). This variation may be rated as a CADASIL clinical variation.

CONCLUSION

The discovery of this mutation site provides an important theoretical basis for a gene-based diagnosis and treatment of recurrent intracranial hemorrhage.

Occurrence of Intracranial Hemorrhage and Associated Risk Factors in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy: A Systematic Review and Meta-Analysis

Background and Purpose

Intracranial hemorrhage (ICH) is thought to be a rare but probably underestimated presentation of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). We conducted a systematic review and meta-analysis with the aim of comprehensively revealing the occurrence of ICH in patients with CADASIL.

Methods

English-language studies published up to September 30, 2021 were searched for in the MEDLINE (PubMed), Web of Science, and Cochrane Library databases. The design, patient characteristics, occurrence rate of ICH, and associated risk factors were retrieved for each identified relevant study.

Results

We enrolled 13 studies in the final meta-analysis, which included 1,310 patients with CADASIL. The probability of ICH occurrence in patients with CADASIL was 10.1% (95% confidence interval [CI]=5.6%–18.0%, I²=85.1%). When stratified by geographic region, the occurrence rate of ICH was much higher in Asians (17.7%; 95% CI=11.0%–28.5%, I²=76.3%) than in Europeans (2.0%; 95% CI=0.4%–10.8%, I²=82.8%). A higher burden of cerebral microbleeds (CMBs) and a history of hypertension were the most commonly recorded risk factors for ICH, which were available for three and two of the included studies, respectively.

Conclusions

Our study suggests that ICH is an important clinical manifestation of CADASIL, especially in Asians. A higher burden of CMBs and the existence of hypertension were found to be associated with a higher probability of ICH occurrence in patients with CADASIL.

R558C NOTCH3 Mutation in a CADASIL Patient with Intracerebral Hemorrhage: A Case Report with Literature Review

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic cerebral small-vessel disease, which is characterized by migraine, recurrent ischemic strokes, psychiatric disorder, progressive cognitive decline, and occasionally intracerebral hemorrhage (ICH). ICH events have been reported in a high proportion of East Asian CADASIL patients with R544C mutation in exon 11 of NOTCH3; however, whether any other specific NOTCH3 mutation determines the ICH phenotype has yet to be explored.

CASE PRESENTATION

We report the case of a 60-year-old male CADASIL patient with a novel R558C mutation in exon 11 of the NOTCH3 gene, who presented with ICH in the basal ganglia and cerebellum. Brain imaging revealed multiple confluent white matter hyperintensities and abundant cerebral microbleeds (CMBs) in the bilateral basal ganglia, thalamus, and cerebellum. The patient had been having recurrent ischemic strokes prior to this ICH event, and had taken antiplatelet and antihypertensive agents for six months. We analyzed the possible reasons for ICH onset in the patient to recommend certain guidelines for the clinic.

CONCLUSIONS

Novel R558C mutation-related CADASIL vasculopathy and numerous CMBs, uncontrolled hypertension, and antiplatelet therapy could collectively contribute to ICH onset in the patient with CADASIL. These findings suggest that a diagnosis of CADASIL should also be considered when patients present with ICH, whenever MRI imaging reveals typical white matter abnormalities. Furthermore, this case report emphasizes the importance of CMB assessment, appropriate blood pressure control, and cautious assessment of the risk-benefits of antiplatelet medication in patients with CADASIL.

CADASIL in Greece: Mutational spectrum and clinical characteristics based on a systematic review and pooled analysis of published cases

BACKGROUND

Differences have been noted in the clinical presentation and mutational spectrum of CADASIL among various geographical areas. The aim of the present study was to investigate the mode of clinical presentation and genetic mutations reported in Greece.

METHODS

After a systematic literature search, we performed a pooled analysis of all published CADASIL cases from Greece.

RESULTS

We identified 14 studies that reported data from 14 families comprising 54 patients. Migraine with aura was reported in 39%, ischemic cerebrovascular diseases in 68%, behavioral-psychiatric symptoms in 47% and cognitive decline in 60% of the patients. The mean (±SD) age of onset for migraine with aura, ischemic cerebrovascular diseases, behavioral-psychiatric symptoms and cognitive decline was 26.2 ± 8.7, 49.3 ± 14.6, 47.9 ± 9.4 and 42.9 ± 10.3, respectively; the mean age at disease onset and death was 34.6 ± 12.1 and 60.2 ± 11.2 years. With respect to reported mutations, mutations in exon 4 were the most frequently reported (61.5% of all families), with the R169C mutation being the most common (30.8% of all families and 50% of exon 4 mutations), followed by R182C mutation (15.4% of all families and 25% of exon 4 mutations).

CONCLUSIONS

The clinical presentation of CADASIL in Greece is in accordance with the phenotype encountered in Caucasian populations, but differs from the Asian phenotype, which is characterized by a lower prevalence of migraine and psychiatric symptoms. The genotype of Greek CADASIL pedigrees is similar to that of British pedigrees, exhibiting a high prevalence of exon 4 mutations, but differs from Italian and Asian populations, where mutations in exon 11 are frequently encountered.

Mutation spectrum and genotype-phenotype correlations in 157 Korean CADASIL patients: a multicenter study

CADASIL is an inherited disease caused by mutations in the NOTCH3 gene. We aimed to investigate the mutation and clinical spectrum, and genotype-phenotype correlations of Korean CADASIL patients. Samples from 492 clinically suspicious patients were collected from four hospitals. Sanger sequencing was performed to screen exons 2 to 25 of the NOTCH3 gene and variants of unknown significance (VUS) were analyzed using the ACMG guidelines. The medical records and MRI data were received from each hospital, for comprehensive analysis of genotype-phenotype correlations. Previously reported NOTCH3 variants were most commonly detected in exon 11 whereas exon 4 was the most common in European studies. The variants were detected equally between the EGFr domains 1-6 and 7-34, which was different from EGFr 1-6 predominant European studies. The average age-of-onset of patients with EGFr 1-6 variants were 4.81 ± 1.95 years younger than patients with EGFr 7-34 variants. Overall, it took Korean patients 51.2 ± 10 years longer to develop CADASIL in comparison to European patients. The most common mutation was p.R544C, which was associated with a later onset of stroke and a significant time-to-event curve difference. We verified four atypical phenotypes of p.R544C that had been reported in previous studies. Eight novel variants in 15 patients were detected but remained a VUS based on the ACMG criteria. This study reported a different EGFr distribution of Korean patients in comparison to European patients and its correlation with a later age-of-onset. An association between a later onset of stroke/TIA and p.R544C was observed.

A Chinese CADASIL Family with a Novel Mutation on Exon 10 of Notch3 Gene

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), which is caused by the Notch3 gene mutation, has its unique clinical and imaging characteristics. Here we present a Chinese family with a novel mutation on exon 10 of Notch3 gene.

METHODS

Clinical and MRI data of the three patients in the family during the 7-year follow-up were collected. The CADASIL Scale Score was calculated to evaluate the disease risk of the three patients at their first admission or clinic visit. Five family members underwent genetic test.

RESULTS

Genetic test confirmed the diagnosis of CADASIL in this family. A novel mutation of p.C533S on exon 10 of Notch3 gene was detected. The CADASIL score of the proband and her sister was both 17 and that of her brother was 14.

CONCLUSIONS

Our report not only expands the mutation spectrum of Notch3 gene in CADASIL, but also shows the distinct heterogeneity of CADASIL patients in the same family with the same mutation.

Genotypic and Phenotypic Characteristics of Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy from China

BACKGROUND AND PURPOSE

Studies have shown characteristics of genotypes and phenotypes in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). This study aimed to describe the clinical and genetic characteristics of and correlations between the genotypes and phenotypes observed in CADASIL in China on the basis of exon classification.

METHODS

Consecutive Chinese patients with CADASIL were evaluated. The detailed clinical and genetic features of CADASIL patients were collected. Genotypic and phenotypic characteristics were compared among 3 CADASIL groups: group 1 included patients with NOTCH3 mutations in exons 3-4, group 2 included those with NOTCH3 mutations in exon 11, and group 3 included those with NOTCH3 mutations in other exons.

RESULTS

A total of 46 patients with CADASIL were evaluated. A comparison of 3 groups with mutations in different NOTCH3 exons revealed that individuals with exon 11 mutations were diagnosed at the oldest age, had the lowest modified Rankin Scale (mRS) scores, and were most likely to have basal ganglia (BG) enlarged perivascular spaces (EPVS) > 20 and atrophy. There were no significant clinical or neuroimaging differences between patients with mutations in exons 3-4 and those with mutations in other exons.

CONCLUSIONS

Clinical and neuroimaging features are different among Chinese patients with mutations in exons 3-4, exon 11, or other exons. Exon 11 showed characterized phenotype (the oldest age at diagnosis, the lowest mRS scores, and were most likely to have BG EPVS > 20 and atrophy), there were no significant differences between exons 3-4 and other exons.

Intracerebral Hemorrhage in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy: Prevalence, Clinical and Neuroimaging Features and Risk Factors

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic cerebral small vessel disease. The role of intracerebral hemorrhage (ICH) in CADASIL remains elusive. The present study aims to investigate the prevalence, characteristics, and risk factors for ICH in CADASIL.

METHODS

This retrospective cross-sectional study investigated ICH and cerebral microbleeds (CMBs) in brain susceptibility-weighted imaging or T2*-weighted gradient-recalled echo images of 127 Taiwanese patients with genetically confirmed CADASIL. We analyzed CMBs, lacunes, white matter hyperintensity, and perivascular space. The total small vessel disease score (range, 0-4) was calculated to estimate the overall magnetic resonance imaging burden of small vessel disease. Multivariate regression analysis was performed to identify factors related to ICH lesions in CADASIL.

RESULTS

Thirty-seven ICH lesions, including 15 symptomatic and 22 asymptomatic lesions, were found in 27 (21.3% [95% CI, 14.0%-30.9%]) of the 127 patients with CADASIL. The thalamus and lobar regions were the most common ICH locations, and 72.7% of the lobar hemorrhages occurred silently. Patients with CADASIL with ICH lesions more often had hypertension and a higher total small vessel disease score than those without ICH (odds ratio [95% CI]: 3.22 [1.25-8.30] and 3.79 [1.51-9.51]). The presence of CMBs in the brain stem and a total CMB count >10 were independently associated with ICH lesions in patients with CADASIL, with odds ratio (95% CI) of 5.82 (1.80-18.80) and 3.83 (1.08-13.67), respectively.

CONCLUSIONS

ICH is an underestimated but important manifestation of CADASIL. The location and number of CMBs are associated with the presence of ICH lesions in patients with CADASIL.

Intracerebral hemorrhage in CADASIL

BACKGROUND

Intracerebral hemorrhage (ICH) has been reported in few cases of Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), mostly in hypertensive patients. We aimed to assess the clinical and radiological characteristics of patients with CADASIL who presented with ICH.

METHODS

A retrospective analysis of all neuroimaging exams of CADASIL patients hospitalized in our academic neurology department for acute cerebrovascular events was performed to find ICH. A systematic review of the literature was performed on this topic.

RESULTS

Including our five patients, a total number of 52 subjects with CADASIL and ICH (mean age: 56 years, SD 11, 36-69%- male) were reported. Intracerebral hemorrhages were mainly deep (34 subjects), followed by lobar (8 subjects), infratentorial (6 subjects) and mixed locations (4 subjects). Three ICHs were asymptomatic. Fourteen patients were taking antithrombotic medication, 18 had no regular antiplatelet or anticoagulant treatment while in 20 patients medical treatment was not detailed. Arterial hypertension was present in 37 out of 51 patients with available information. Neuroimaging showed extensive FLAIR hyperintensities in all CADASIL subjects with ICH, cerebral microbleeds in all but three patients, and lacunar infarction in 19 out of 25 subjects with available information.

CONCLUSIONS

Intracerebral hemorrhage represents a possible yet uncommon manifestation of CADASIL and should be considered as a possibility in patients with ICH associated with leukoencephalopathy and microbleeds, even in the absence of other clinical symptoms.

Apolipoprotein E ε4 Is Associated With the Development of Incident Dementia in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Patients With p.Arg544Cys Mutation

Background and Purpose

To identify clinical, laboratory, and magnetic resonance imaging (MRI) features in predicting incident stroke and dementia in Korean patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

Materials and Methods

We enrolled 87 Korean CADASIL patients who had undergone baseline clinical, laboratory, and MRI examinations between March 2012 and February 2015. The primary outcome of this study is the occurrence of stroke and dementia during the study period. The occurrence of incident stroke was confirmed by neuroimaging study, and dementia was defined by the diagnostic and statistical manual of mental disorders, fourth edition, criteria.

Results

Of the 87 patients, 57.5% were men, and the mean age was 63 ± 13 years (range 34–90 years), and 82 patients (94.3%) had p.Arg544Cys mutation. During an average follow-up of 67 months (interquartile range: 53–69 months), incident stroke occurred in 14 of 87 patients (16.1%) and incident dementia in 7 of 70 non-demented patients (10.0%). In adjusted analysis, increased systolic blood pressure was associated with increased risk of incident stroke [for every 10-mmHg increase; hazard ratio, 1.44 (1.02–2.03)]. Apolipoprotein E ε4 genotype was associated with an increased risk of incident dementia [hazard ratio, 10.70 (1.27–89.88)].

Conclusion

In this study, apolipoprotein E ε4 genotype was associated with the development of incident dementia, and higher blood pressure was associated with increased risk of incident stroke in CADASIL patients with predominant p.Arg544Cys mutation.

Clinical and imaging features of patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and cysteine-sparing NOTCH3 mutations

Background

Characteristics of patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and cysteine-sparing NOTCH3 mutations are relatively unknown. This study compared clinical and imaging characteristics between patients with CADASIL and cysteine-sparing NOTCH3 mutations and those with CADASIL and cysteine-involving NOTCH3 mutations.

Methods

We retrospectively reviewed medical records of patients with CADASIL admitted to the Asan Medical Center between September 1999 and September 2017. We compared clinical and brain magnetic resonance imaging (MRI) characteristics based on the presence or absence of cysteine-involving NOTCH3 gene mutations. We compared white matter change frequencies and grades in specific spatial regions between the groups according to age-related white matter change (ARWMC) scores. We evaluated the presence, number, and anatomical distributions of cerebral microbleeds according to the microbleed anatomical rating scale.

Results

We reviewed data from 79 patients (55 cysteine-involving, 24 cysteine-sparing NOTCH3 mutations). Clinical symptoms and signs did not differ significantly between the groups. The white matter change frequency and ARWMC scores (adjusted for age and stroke risk factors) in the anterior temporal lobes were lower in cysteine-sparing patients than in cysteine-involving patients. Frequencies and grades of the other brain region’s white matter changes and cerebral microbleeds were similar between the groups.

Conclusions

Patients with CADASIL and cysteine-sparing NOTCH3 mutations showed less involvement of the anterior temporal lobes in brain MRI than those with CADASIL and cysteine-involving NOTCH3 mutations, although both groups showed similar clinical characteristics.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy revisited: Genotype-phenotype correlations of all published cases

Objective

The aim of this study was to evaluate the correlation between the various NOTCH3 mutations and their clinical and genetic profile, along with the presentation of a novel mutation in a patient.

Methods

Here, we describe the phenotype of a patient with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) harboring a novel mutation. We also performed an extensive literature research for NOTCH3 mutations published since the identification of the gene and performed a systematic review of all published cases with NOTCH3 mutations. We evaluated the mutation pathogenicity in a great number of patients with detailed clinical and genetic evaluation and investigated the possible phenotype-genotype correlations.

Results

Our patient harbored a novel mutation in the NOTCH3 gene, the c.3084 G > C, corresponding to the aminoacidic substitution p.Trp1028Cys, presenting with seizures as the first neurologic manifestation. We managed to find a correlation between the pathogenicity of mutations, severity of the phenotype, and age at onset of CADASIL. Significant differences were also identified between men and women regarding the phenotype severity.

Conclusions

The collection and analysis of these scarce data published since the identification of NOTCH3 qualitatively by means of a systematic review and quantitatively regarding genetic profile and pathogenicity scores, highlight the significance of the ongoing trend of investigating phenotypic genotypic correlations.

Plasma neurofilament light chain and glial fibrillary acidic protein predict stroke in CADASIL

Background

Stroke remains the most cumbersome disease burden in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). This study aimed to investigate whether plasma biomarkers can reflect disease severity and predict stroke recurrence in CADASIL patients.

Methods

Sixty-three CADASIL patients (mean age 58.9 ± 9.3 years old, male 63%) from a multicenter registry and 17 controls were recruited. Plasma biomarkers, namely neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), tau, and ubiquitin carboxy-terminal hydrolase L1 (UCHL1), were measured using an ultra-sensitive single molecule array at baseline. Neuroimaging markers assessed included the Fazekas scale of white matter hyperintensity, numbers of lacunes, and cerebral microbleeds (CMBs). Cox proportional hazards regression models were applied to calculate the hazard ratio (HR) of plasma biomarkers at baseline for predicting incident stroke during follow-up.

Results

Plasma NfL, GFAP, and UCHL1 levels were significantly elevated in the CADASIL patients than in the controls. Among the CADASIL patients, both plasma NfL and GFAP levels positively correlated with the numbers of CMBs (r = 0.32 and r = 0.37, respectively; both p < 0.05). Higher plasma levels of NfL and GFAP were associated with any stroke (odds ratio 2.02, 95% confidence interval [CI] 1.06–3.87) and ICH (odds ratio 2.06, 95% CI 1.26–3.35) at baseline, respectively. Within a mean follow-up period of 3.1 ± 2.1 years, 10 patients (16%) had incident stroke and 6 of them were ICH. Higher baseline NfL (HR 1.93, 95% CI 1.19–3.13) predicted any incident stroke, whereas higher GFAP (HR 2.80, 95% CI 1.21–6.53) predicted incident ICH.

Conclusions

In CADASIL patients, plasma NfL can be a promising biomarker for monitoring incident stroke, whereas GFAP may have a role in cerebral hemorrhage.

Phenotypic characterization of CADASIL patients with the Arg332Cys mutation in the NOTCH3

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary vascular disease caused by mutations in NOTCH3, that are primarily localized in exons 4, 3, and 11. The Arg332Cys mutation in exon 6 has been rarely reported in patients with CADASIL.

METHODS

A case study and the results of a comprehensive systemic search of the PubMed database, using the keywords "CADASIL", "Arg332Cys", "R332C", and "exon 6", are reported. The results obtained, combined with the data obtained from the largest published case series on CADASIL, the clinical and imaging characteristics of patients with the Arg332Cys mutation, were compared and analyzed.

RESULTS

A 48-year-old woman with a rare Arg332Cys mutation in exon 6 of NOTCH3, who presented with rapidly developing dementia and recurrent ischemic stroke, was investigated herein. Magnetic resonance imaging (MRI) revealed abnormal signals in the cerebral white matter, bilateral thalamus, internal and external capsules, basal ganglia, corpus callosum, and brainstem. Literature review identified an additional 21 individuals, comprising 11 Europeans and 10 Asians, with the Arg332Cys mutation; of these identified individuals, clinical data was available for 2 Italian and 9 Asian patients. Analysis of the clinical characteristics of the 11 patients and the patient we reported showed that their mean age at disease onset was 
37.82±9.36 years, much earlier than 57.0±9.36 years reported in literature. The most frequent manifestations were transient ischemic stroke or stroke (83.3%), followed by cognitive impairment (58.3%), psychiatric symptoms (50%), and migraine (33.3%). Among the 10 Asian patients with available imaging data, the characteristic high signals for the external capsule and brainstem accounted for 90% and 71.43% respectively, and anterior temporal high signal took proportion of 60% (higher than 34.5% reported for Asian patients in literature). None of the 6 patients with available gradient echo imaging data had cerebral microbleeding.

CONCLUSIONS

CADASIL patients with the Arg332Cys mutation in exon 6 have been reported in Europe and Asia. The majority of patients had early disease onset. Diffuse high signals involving the external capsule, brainstem, and bilateral temporal pole are the main neuroimaging characteristics.

NOTCH3 cysteine-altering variant is an important risk factor for stroke in the Taiwanese population

OBJECTIVE

To test the hypothesis that the prevalence and clinical effect of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) have been underestimated in Asian populations.

METHODS

The Taiwan Biobank, containing 1,517 Taiwanese genome sequences, was queried for pathogenic NOTCH3 cysteine-altering mutations. NOTCH3 mutations identified in the reference population were genotyped in 7,038 stroke- and dementia-free individuals and 800 patients with ischemic stroke. NOTCH3 genotyping, clinical manifestations, and the severity of white matter lesions on MRI were compared between the 2 groups.

RESULTS

Three cysteine-altering NOTCH3 variants (p.R544C, p.C853Y, and p.C884Y) were identified from the Taiwan Biobank. We confirmed that the NOTCH3 p.R544C mutation was present in a significant number of individuals in Taiwan, including 60 of the 7,038 healthy controls (0.9%), 17 of the 800 patients with ischemic stroke (2.1%), and 16 of the 245 patients with small vessel occlusion (SVO) stroke (6.5%). The other 2 cysteine-altering mutations were rarely detected. After adjusting for vascular risk factors, harboring the p.R544C variant resulted in a 3.40-fold increased risk for overall stroke and an 11.05-fold increased risk for SVO stroke (p = 0.0001 and 3.9 × 10^-10, respectively). Three symptom-free individuals carrying the p.R544C mutation had extensive leukoencephalopathy typical of CADASIL at age 59, 66, and 67, suggesting that p.R544C-related CADASIL could remain subclinical at advanced age.

CONCLUSION

The NOTCH3 p.R544C variant is an important risk factor for SVO stroke in Taiwan. Phenotypic variation among individuals carrying a NOTCH3 mutation indicates the existence of disease-modifying factors in CADASIL.

Clinical Features of 4 Novel NOTCH3 Mutations of Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy in China

Background

This study aimed to identify NOTCH3 mutations and describe the genetic and clinical features and magnetic resonance imaging results in 11 unrelated patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) from Henan province in China.

Material/Methods

NOTCH3 was directly sequenced in 11 unrelated patients of Chinese descent. The clinical presentations and magnetic resonance imaging features were retrospectively analyzed in the 11 index patients with a definite diagnosis.

Results

Seven different mutations were identified in 11 unrelated patients, including 4 novel mutations (p.P167S, p.P652S, p.C709R, and p.R1100H) in China and 3 reported mutations (p.C117R, p.R578C, and p.R607C). Four novel mutations (p.P167S, p.P652S, p.C709R, and p.R1100H) were predicted to be probably pathogenic using an online pathogenicity prediction program through comprehensive analysis. Clinical presentations in symptomatic patients included stroke, cognitive decline, psychiatric disturbances, and migraine. Multiple lacunars infarcts and leukoaraiosis were detected on MRI in most symptomatic patients, while white-matter lesions were identified in the temporal pole or the external capsule in all affected patients.

Conclusions

The mutation spectrum of CADASIL patients from Henan province in China displayed some differences from that of those reported previously. DNA sequencing was used to diagnose all 11 patients as having CADASIL, and we found 4 novel mutations. The present results further contribute to the enrichment of NOTCH3 mutation databases.

Novel Characteristics of Race-Specific Genetic Functions in Korean CADASIL

Background and Objectives: Previous studies found differences in the characteristics of NOTCH3 mutations in Caucasians and Asians with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Therefore, we sought to investigate the correlations between genetic and clinical/radiological findings in Korean CADASIL patients including some variants of unknown significance (VUS). Materials and Methods: We screened 198 patients with a suspected diagnosis of CADASIL between 2005 and 2015 via Sanger sequencing. Results: A total of 34 subjects (52.5 ± 9.5 years) were included. The majority of the mutations were in exon 3 and exon 11. R75P mutations (n = 5), followed by Y465C and R544C mutations (n = 4) were the most prevalent. Patients with those mutations exhibited less frequent anterior temporal (AT) or external capsular (EC) hyperintensities compared to patients with other locus mutations. Hemorrhagic stroke (HS) was found to be associated with mutations in exon 3 (R75P), exon 9 (Y465C), exon 11 (R587C), and exon 22 (R1175W variants), which were common locations in our study. Although it is unclear that genetic differences might affect the phenotypes in ethnicities, Asian population shows less migraine or seizure, but more intracerebral hemorrhage. Unlike in westernized countries, typical AT or EC hyperintensities may not be significant MRI markers, at least in Korean CADASIL patients. Furthermore, similar to R75P phenotypes, it is a novel finding that patients with Y465C and R1175W VUS have less frequent AT involvement than Caucasians. Conclusion: The associations between HS and common genetic locations account for the increased development of intracerebral hemorrhage in Koreans rather than Caucasians. We suggest that some CADASIL mutations appear to impart novel region-specific characteristics.

A Study of Congenital Protein C Deficiency With Infancy Onset of CADASIL in a Chinese Baby

OBJECTIVE

The main objectives of this article were to study a severe congenital protein C deficiency (PCD) in a patient with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and analyze the cause of this case.

MATERIALS AND METHODS

We had recorded clinical manifestations of the patient, laboratory tests, imaging studies, and gene sequencing of the PROC gene and NOTCH3 gene to study the disease in this family. We checked the change of NOTCH3 protein by immunohistochemistry.

RESULTS

Laboratory studies of the patient had revealed that his PC activity was 3%. Magnetic resonance imaging results showed hyperintense lesions in the cerebral white matter of the patient. PROC gene and NOTCH3 gene sequencing was performed among the family members. The patient was confirmed as homozygous for the (A-G)-12 at the transcription initiation site in the promoter region of the PROC gene and heterozygous mutation of the NOTCH3 gene. Immunohistochemical results showed that NOTCH3 protein was positive in the skin vascular smooth muscle of the patient.

CONCLUSIONS

We studied a rare case of an infat boy diagnosed with both congenital PCD and CADASIL; congenital PCD was attributable to a compound that was homozygous for (A-G)-12 at the transcription initiation site in the promoter region of the PROC gene, and CADASIL was caused by missense mutation in exon 24 of NOTCH3. He was a sporadic patient with congenital PCD and CADASIL; it maybe that the deficiency of protein C led to early onset of CADASIL. The gene sequencing of PROC gene and NOTCH3 gene may have important value for fertility guidance and prenatal diagnosis.

Comparison of brain magnetic resonance imaging between myotonic dystrophy type 1 and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Background

Anterior temporal lobe hyperintensities detected by brain MRI are a recognized imaging hallmark of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Because similar findings may be present in patients with myotonic dystrophy type 1 (DM1), the brain MRI in these two diseases is often misinterpreted. We compared the MRI findings between the two entities to examine whether they display distinctive characteristics.

Methods

This retrospective, cross-sectional study reviewed medical records of patients with DM1 or CADASIL admitted to Asan Medical Center between September 1999 and September 2017. We compared the frequency and grades of white matter changes in specific spatial regions between the groups according to age-related white matter change scores. We also evaluated the presence of cerebral microbleeds.

Results

A total of 29 patients with DM1 and 68 with CADASIL who had undergone MRI were included in the analysis. The overall prevalence of white matter hyperintensities was 20 (69%) and 66 (97%) in DM1 and CADASIL, respectively (p < 0.001), whereas the frequency of anterior temporal lobe hyperintensities was comparable between the groups (10 [34.5%] in DM1 vs. 35 [51.5%] in CADASIL, p = 0.125). The brain MRI of patients with DM1 revealed more limited involvement of the frontal, parieto-occipital, external capsule and basal ganglia regions compared with imaging in patients with CADASIL. Cerebral microbleeds were not observed in any case of DM1 but were present in 31 of 45 (68.9%) cases of CADASIL.

Conclusions

Anterior temporal lobe involvement in DM1 is not infrequent compared with CADASIL. However, because brain MRI in patients with DM1 lacks other distinctive features seen in CADASIL, imaging might assist in differentiating these two conditions.

Prevalence and clinical characteristics of stroke patients with p.R544C NOTCH3 mutation in Taiwan

Objective

Features of cerebral autosomal dominant arteriopathy with subcortical infarct and leukoencephalopathy (CADASIL) caused by NOTCH3 mutations vary between ethnicities and regions. In Taiwan, more than 70% of CADASIL patients carry the mutation hot spot of p.R544C. We investigated the prevalence of NOTCH3 p.R544C mutation in stroke patients in Taiwan.

Methods

This prospective, multicenter study recruited acute stroke patients within 10 days of symptom onset. The p.R544C mutation was identified by polymerase chain reaction with confronting two‐pair primers and sequencing. Clinical parameters, vascular risk factors, stroke subtypes, and stroke outcomes were analyzed.

Results

Of the 1970 stroke patients (mean age 61.1 ± 13.6 years, male 69.5%) included, 1705 (86.5%) had ischemic stroke and 265 (13.5%) had intracerebral hemorrhage. The prevalence of p.R544C in the study population was 2.8% (95% confidence interval [CI] = 2.1–3.5%). The prevalence was highest in patients with small vessel occlusion type of ischemic stroke (5.6%), followed by intracerebral hemorrhage (5.3%), and infarct of undetermined etiology (2.7%), and was low in patients with cardioembolism (0.8%) and large artery atherosclerosis (0.7%). All p.R544C patients with intracerebral hemorrhage were nonlobar hemorrhage. Sibling history of stroke (odds ratio [OR] = 4.50, 95% CI = 1.67–12.14 in ischemic stroke; OR = 6.03, 95% CI = 1.03–35.47 in intracerebral hemorrhage, respectively) and small vessel occlusion (OR, 4.03, 95% CI, 1.26–12.92) were significantly associated with p.R544C.

Interpretation

p.R544C NOTCH3 mutation is underdiagnosed in stroke patients in Taiwan, especially in those with small vessel occlusion and sibling history of stroke.

CADASIL

Cerebral small-vessel disease is a prevalent condition that is strongly associated with ischemic stroke and dementia. The most prevalent inherited cause of cerebral small-vessel disease is CADASIL, cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy, a disorder linked to mutations in NOTCH3. The most common symptoms of CADASIL are small ischemic strokes and/or transient ischemic attacks and cognitive impairment, appearing in middle age, that may progress to frank vascular dementia. However, it is increasingly recognized that individual symptom types, onset, and disease severity span a wide spectrum, even among individuals in the same family. Magnetic resonance imaging in CADASIL reveals severe white-matter hyperintensities, evidence of prior subcortical strokes, and, in some cases, microhemorrhages. Several hundred mutations in NOTCH3 have been described worldwide in CADASIL, and virtually all of these mutations alter the cysteine content of the extracellular NOTCH3 gene product. This molecular genetic signature of CADASIL has led to the hypothesis that structural abnormalities in the vascular smooth-muscle protein NOTCH3 trigger arterial degeneration, vascular protein accumulation, and cerebrovascular failure.

Clinical features and mutation spectrum in Chinese patients with CADASIL: A multicenter retrospective study

AIM

To characterize clinical features and mutation spectrum in Chinese patients with CADASIL.

METHODS

We collected 261 clinically suspected Chinese CADASIL patients from three hospitals located in different regions of China. Sanger sequencing is performed to screen the exons 2 to 24 of NOTCH3 gene. Clinical and genetic data were retrospectively studied. Haplotype analyses were performed in patients carrying p.Arg544Cys and p.Arg607Cys, respectively.

RESULTS

A total of 214 patients were finally genetically diagnosed as CADASIL, with 45 known NOTCH3 mutations and a novel c.1817G>T mutation. We found that patients carrying p.Arg607Cys or p.Arg544Cys mutation located in exon 11 occupied nearly 35% in our mutation spectrum. In retrospectively study of clinical data, we found a higher number of patients having cognitive impairment and a lower number of patients having migraine with aura. Furthermore, we identified that patients carrying mutations in exon 11 seemed to experience a later disease onset (p=6.8×10^-5 ). Additionally, a common haplotype was found in patients from eastern China carrying p.Arg607Cys, and the patients from Fujian carrying p.Arg544Cys shared the same haplotype with patients from Taiwan carrying p.Arg544Cys.

CONCLUSIONS

These findings broaden the mutational and clinical spectrum of CADASIL and provide additional evidences for the existence of founder effect in CADASIL patients.

First Report of Arg587Cys Mutation of Notch3 Gene in Two Chinese Families with CADASIL

OBJECTIVE

To explore Notch3 mutation sites of Chinese patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

METHODS

Direct sequencing of all exons in Notch3 gene was performed on 12 unrelated suspected CADASIL cases from mainland China.

RESULT

A missense p.Arg587Cys (1759C>T) mutation in exon 11 was identified in 2 patients through genetic analysis.

CONCLUSION

Chinese patients with CADASIL of R587C mutation in exon 11 was firstly reported.

CADASIL: two new cases with intracerebral hemorrhage

Whether cerebral autosomal‐dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a risk factor for spontaneous intracerebral hemorrhage (ICH) and influences outcomes remains unclear. In this study, we report two cases of CADASIL presenting with cerebral hemorrhages. These cases suggest that a CADASIL vasculopathy by itself mainly results in ICH, as indicated by slight vascular risk factors and prominent neuroimaging abnormalities, suggesting that CADASIL should be considered a risk factor for ICH. Interestingly, decreased perihematomal edema was noted in ICH patients with CADASIL in this study.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) as a model of small vessel disease: update on clinical, diagnostic, and management aspects

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common and best known monogenic small vessel disease. Here, we review the clinical, neuroimaging, neuropathological, genetic, and therapeutic aspects based on the most relevant articles published between 1994 and 2016 and on the personal experience of the authors, all directly involved in CADASIL research and care. We conclude with some suggestions that may help in the clinical practice and management of these patients.

Archetypal NOTCH3 mutations frequent in public exome: implications for CADASIL

Objective

To determine the frequency of distinctive EGFr cysteine altering NOTCH3 mutations in the 60,706 exomes of the exome aggregation consortium (ExAC) database.

Methods

ExAC was queried for mutations distinctive for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), namely mutations leading to a cysteine amino acid change in one of the 34 EGFr domains of NOTCH3. The genotype‐phenotype correlation predicted by the ExAC data was tested in an independent cohort of Dutch CADASIL patients using quantified MRI lesions. The Dutch CADASIL registry was probed for paucisymptomatic individuals older than 70 years.

Results

We identified 206 EGFr cysteine altering NOTCH3 mutations in ExAC, with a total prevalence of 3.4/1000. More than half of the distinct mutations have been previously reported in CADASIL patients. Despite the clear overlap, the mutation distribution in ExAC differs from that in reported CADASIL patients, as mutations in ExAC are predominantly located outside of EGFr domains 1–6. In an independent Dutch CADASIL cohort, we found that patients with a mutation in EGFr domains 7–34 have a significantly lower MRI lesion load than patients with a mutation in EGFr domains 1–6.

Interpretation

The frequency of EGFr cysteine altering NOTCH3 mutations is 100‐fold higher than expected based on estimates of CADASIL prevalence. This challenges the current CADASIL disease paradigm, and suggests that certain mutations may more frequently cause a much milder phenotype, which may even go clinically unrecognized. Our data suggest that individuals with a mutation located in EGFr domains 1–6 are predisposed to the more severe “classical” CADASIL phenotype, whereas individuals with a mutation outside of EGFr domains 1–6 can remain paucisymptomatic well into their eighth decade.

The comparisons of phenotype and genotype between CADASIL and CADASIL-like patients and population-specific evaluation of CADASIL scale in China

Background

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common form of hereditary stroke disorder caused by mutations in the NOTCH3 gene. Although CADASIL scale is a widely used tool to screen clinically suspected CADASIL patients, the differential effects of this scale in various populations remain unknown.

Methods

92 CADASIL-like patients and 24 CADASIL patients were selected based on CADASIL scale and gene tests. The clinical, genetic and radiological characteristics were analyzed.

Results

Based on the CADASIL scale, we first screened 116 suspected CADASIL patients, and detected 20 mutations in 24 CADASIL-patients (Specificity: 20.69 %). Surprisingly, we found that transient ischemic attack/stroke, migraine, cognitive decline, psychiatric disturbances and early onset age in CADASIL scale showed no differences between the CADASIL and the CADASIL-like patients (p > 0.05). Instead, recurrent cerebral ischemic events (58.33 %, p = 0.028) and positive family histories (p < 0.05) were more frequently observed in CADASIL patients. Moreover, compared with CADASIL-like patients (21.74 %), CADASIL patients demonstrated higher percentage of temporal pole involvements (58.33 %, p = 0.001), but not the external capsule involvements (66.67 %, p = 0.602), in MRI imaging. Further, we found that vascular risk factors could occur in both CADASIL patients and CADASIL-like patients, and therefore could not be used as the markers to differentiate the two groups in our study (p > 0.05). By performing DSA analysis, we for the first time identified dysplasia of cerebral blood vessels in CADASIL patients, which were detected more frequently in CADASIL patients (41.67 %) in comparison with CADASIL-like patients (8.69 %, p <0.01).

Conclusion

Our data suggested that the efficacy of CADASIL scale to diagnose the disease varied with specific populations. Recurrent cerebral ischemic events, temporal pole involvements (but not the external capsule) in MRI imaging and dysplasia of cerebral blood vessels in DSA may be the new potential risk factors of the CADASIL scale suitable for Chinese patients. Gene testing by encephalopathy gene panel is expected to improve the accuracy of CADASIL differential diagnosis and increase the understanding of this disease in the future.

APOE and AGT in the Finnish p.Arg133Cys CADASIL population

BACKGROUND

CADASIL is an inherited systemic small vessel disease, the affected status of brain vessels leading to subcortical vascular dementia. The defective gene is NOTCH3 in which over 230 different pathogenic mutations have been identified. The clinical course of CADASIL is highly variable even within families. Previous studies have shown that additional genetic factors modify the phenotype.

AIMS AND METHODS

Altogether, 134 Finnish CADASIL patients with p.Arg133Cys mutation were analysed for possible associations between the apolipoprotein E (APOE) genotype, angiotensinogen (AGT) p.Met268Thr polymorphism or neutral p.Ala202Ala NOTCH3 polymorphism and earlier first-ever stroke or migraine.

RESULTS

We found no association between the APOE genotypes, AGT polymorphism, NOTCH3 polymorphism and earlier first-ever stroke or migraine.

CONCLUSIONS

The APOE, AGT and NOTCH3 polymorphism did not modify the onset of strokes or migraine in our CADASIL sample, which is one of the largest mutationally homogenous CADASIL populations published to date. International collaboration, pooled analyses and genomewide approaches are warranted to identify the genetic factors that modify the highly variable CADASIL phenotype.

Characterization of CADASIL among the Han Chinese in Taiwan: Distinct Genotypic and Phenotypic Profiles

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is originally featured with a strong clustering of mutations in NOTCH3 exons 3–6 and leukoencephalopathy with frequent anterior temporal pole involvement. The present study aims at characterizing the genotypic and phenotypic profiles of CADASIL in Taiwan. One hundred and twelve patients with CADASIL from 95 families of Chinese descents in Taiwan were identified by Sanger sequencing of exons 2 to 24 of NOTCH3. Twenty different mutations in NOTCH3 were uncovered, including 3 novel ones, and R544C in exon 11 was the most common mutation, accounting for 70.5% of the pedigrees. Haplotype analyses were conducted in 14 families harboring NOTCH3 R544C mutation and demonstrated a common haplotype linked to NOTCH3 R544C at loci D19S929 and D19S411. Comparing with CADASIL in most Caucasian populations, CADASIL in Taiwan has several distinct features, including less frequent anterior temporal involvement, older age at symptom onset, higher incidence of intracerebral hemorrhage, and rarer occurrence of migraine. Subgroup analyses revealed that the R544C mutation is associated with lower frequency of anterior temporal involvement, later age at onset and higher frequency of cognitive dysfunction. In conclusion, the present study broadens the spectrum of NOTCH3 mutations and provides additional insights for the clinical and molecular characteristics of CADASIL patients of Han-Chinese descents.

Aetiological diagnosis of middle-aged and elderly cryptogenic ischaemic cerebral vascular disease

Although tremendous efforts have been made to explore the potential aetiologies of cryptogenic ischaemic cerebral vascular disease (CICVD), it remains a great challenge for neurologists to get a comprehensive picture of CICVD across the world. Part of the reason why is that the vast majority of studies have focussed on CICVD in young stroke patients while the underlying causes of CICVD in middle-aged or elderly stroke population have not been fully investigated. The focus of this paper has been dedicated to review the different studies that explore the aetiologies of CICVD cases in this patient population. While there is a set of heterogeneous causes that can lead to CICVD in middle-aged and elderly patients, our review reveals that emboli originated from or across occult places within the heart or produced by transient arrhythmias could possibly be the main culprit. Dislodged aortic plaques might also account for certain CICVD cases and in fewer cases, hereditary arteriopathy and thrombophilia can also play a role. The aforementioned factors have similar roles in middle-aged and elderly CICVD patients as in their younger counterparts. However, more studies are needed to explore the role of these factors in older patients.

Genotypic and phenotypic spectrum of CADASIL in Japan: the experience at a referral center in Kumamoto University from 1997 to 2014

This study elucidates the genotypic and phenotypic spectrum and histopathological findings related to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in Japan. For this single-center retrospective observational study, we enrolled 215 patients who were clinically suspected of having CADASIL and were examined at Kumamoto University from 1997 to 2014, and we diagnosed CADASIL in 70 patients. We found 19 different NOTCH3 mutations in the patients, with the NOTCH3 Arg133Cys mutation being found most frequently. We also found the Arg75Pro mutation, a cysteine-sparing NOTCH3 mutation. CADASIL patients with this Arg75Pro mutation were frequently found throughout Japan, and fewer patients with the Arg75Pro mutation showed MRI hyperintensity in the anterior temporal pole compared with patients with other NOTCH3 mutations. Significantly more CADASIL patients with the NOTCH3 Arg133Cys mutation had hyperintensity in the external capsule compared with CADASIL patients with the other mutations not including the NOTCH3 Arg75Pro mutation. We also showed postmortem pathological findings of the first Japanese CADASIL case with the NOTCH3 Arg133Cys mutation, and histopathological findings of fresh frozen skin biopsy specimens of CADASIL patients. In conclusions, the spectrum of NOTCH3 mutations in Japanese CADASIL patients may be partially explained by founder effects. Genotype-phenotype correlations may exist in CADASIL, which should be considered so as to make an accurate diagnosis of CADASIL in each population. Fresh frozen skin biopsy specimens may aid detection of Notch3 deposits on vascular walls for an improved diagnosis of CADASIL.

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.

Imaging characteristics of cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL)

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is an autosomal dominant vascular disorder. Diagnosis and follow-up in patients with CADASIL are based mainly on magnetic resonance imaging (MRI). MRI shows white matter hyperintensities (WMHs), lacunar infarcts and cerebral microbleeds (CMBs). WMHs lesions tend to be symmetrical and bilateral, distributed in the periventricular and deep white matter. The anterior temporal lobe and external capsules are predilection sites for WMHs, with higher specificity and sensitivity of anterior temporal lobe involvement compared to an external capsule involvement. Lacunar infarcts are presented by an imaging signal that has intensity of cerebrospinal fluid in all MRI sequences. They are localized within the semioval center, thalamus, basal ganglia and pons. CMBs are depicted as focal areas of signal loss on T2 images which increases in size on the T2*-weighted gradient echo planar images ("blooming effect").

De novo mutation in the NOTCH3 gene causing CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is one of the most common hereditary forms of stroke, and migraine with aura, mood disorders and dementia. CADASIL is caused by mutations of the NOTCH3 gene. This mutation is inherited as an autosomal dominant trait. Most individuals with CADASIL have a parent with the disorder. In extremely rare cases, CADASIL may occur due to a spontaneous genetic mutation that occurs for unknown reasons (de novo mutation). We report a new case of patient with de novo mutation of the NOTCH3 gene and a condition strongly suggestive of CADASIL (migraine, stroke, and white matter abnormalities), except that this patient did not have any first-degree relatives with similar symptoms.

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.

CADASIL and CARASIL

CADASIL and CARASIL are hereditary small vessel diseases leading to vascular dementia. CADASIL commonly begins with migraine followed by minor strokes in mid-adulthood. Dominantly inherited CADASIL is caused by mutations (n > 230) in NOTCH3 gene, which encodes Notch3 receptor expressed in vascular smooth muscle cells (VSMC). Notch3 extracellular domain (N3ECD) accumulates in arterial walls followed by VSMC degeneration and subsequent fibrosis and stenosis of arterioles, predominantly in cerebral white matter, where characteristic ischemic MRI changes and lacunar infarcts emerge. The likely pathogenesis of CADASIL is toxic gain of function related to mutation-induced unpaired cysteine in N3ECD. Definite diagnosis is made by molecular genetics but is also possible by electron microscopic demonstration of pathognomonic granular osmiophilic material at VSMCs or by positive immunohistochemistry for N3ECD in dermal arteries. In rare, recessively inherited CARASIL the clinical picture and white matter changes are similar as in CADASIL, but cognitive decline begins earlier. In addition, gait disturbance, low back pain and alopecia are characteristic features. CARASIL is caused by mutations (presently n = 10) in high-temperature requirement. A serine peptidase 1 (HTRA1) gene, which result in reduced function of HTRA1 as repressor of transforming growth factor-β (TGF β) -signaling. Cerebral arteries show loss of VSMCs and marked hyalinosis, but not stenosis.

Clinical and radiological features in CADASIL and NOTCH3-negative patients: a multicenter study from Turkey

BACKGROUND

The diversity of clinical presentation and neuroimaging findings of CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) from different regions of the world has not yet been studied in depth. Here we investigated the variability of clinical, radiological and genetic data of 48 patients analyzed for NOTCH3 mutation in Turkey.

METHODS

Clinical evaluation was made according to a preformed questionnaire. Cranial neuroimaging findings were determined on the basis of T1, T2, FLAIR and proton-density magnetic resonance scans. For genetic analysis, polymerase chain reaction was performed with primers flanking exons 2-6 and 11 of NOTCH3 gene.

RESULTS

Twenty-five patients (52.1%) were diagnosed as CADASIL with NOTCH3 mutation, while 23 patients (47.9%) had no mutation (NOTCH3-negative patients). The mean age and age at stroke onset were lower in male CADASIL patients (p < 0.03). A family history of migraine (p = 0.012), stroke (p < 0.001), recurrent strokes (p = 0.020) and dementia (p = 0.012) was more common in CADASIL patients. Temporal pole involvement was more common in CADASIL patients (p = 0.004).

CONCLUSION

It is of clinical importance to identify the heterogeneity of CADASIL from different countries due to a low correlation of clinical and radiological data with respect to NOTCH3 mutation.

Cognitive profile of CADASIL patients with R544C Notch3 mutation

BACKGROUND

Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited microangiopathy caused by mutations in the Notch3 gene. In the present study, we aimed to analyze cognitive and neuroimaging profiles of CADASIL patients with R544C mutation.

METHODS

Fifty-eight consecutive patients with R544C mutation and 26 normal controls were investigated. The patients were divided into two groups depending on the presence (CADASIL with dementia: CADASIL-D) or absence of dementia (CADASIL no dementia: CADASIL-ND). We applied the same neuropsychological test to the three groups. Brain magnetic resonance images were obtained from 58 patients with R544C mutation. Linear regression models were used to assess the impact of lacunes and white matter hyperintensities on cognitive function in the CADASIL-ND group.

RESULTS

Compared to controls, the CADASIL-ND group demonstrated significant difficulties concerning measures of attention, executive function, and motor control. The CADASIL-D group was impaired in all cognitive domains that were assessed, except the language domain. After correction for age and educational level, the number of lacunes was associated with lower scores in the Alzheimer's Disease Assessment Scale cognitive subtest and Stroop color test in the CADASIL-ND group.

CONCLUSIONS

Non-Caucasian CADASIL patients with R544C mutation and Caucasian CADASIL patients show similar patterns of cognitive impairment.

Spontaneous intracerebral hemorrhage in CADASIL

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary small vascular disease and its mainly clinical manifestations are ischemic events. Spontaneous intracerebral hemorrhage (ICH) involvement in patients with CADASIL is extremely uncommon.

CASE REPORT

A 46-year-old normotensive Chinese man developed a large hematoma in the left basal ganglia after he was diagnosed with CADASIL 2 months ago, the patient did not take any antithrombotics. Susceptibility weighted imaging at pre-ICH showed multiple cerebral microbleeds (CMBs) in the bilateral basal ganglia. He experienced migraine at about 10 months post-ICH. To our knowledge, this is the first report of ICH in CADASIL patients with Arg90Cys mutation in exon 3.

DISCUSSION AND CONCLUSIONS

ICH should be considered when evaluating new attacks in CADASIL patients. Thus, MRI screening for CMBs might be helpful in predicting the risk of ICH and guiding antithrombotic therapy. In addition, strict control of hypertension and cautious use of antithrombotics may be important in this context.

Spectrum of NOTCH3 mutations in Korean patients with clinically suspicious cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by mutations in the NOTCH3 gene on chromosome 19. Previous studies showed that NOTCH3 contains mutational hotspots that can vary among individuals of different ethnic backgrounds. In this study, we investigated the spectrum of NOTCH3 mutations in Korean patients with CADASIL. We retrospectively analyzed 156 patients who underwent NOTCH3 gene testing for molecular diagnosis of CADASIL using Sanger sequencing with a tiered approach. First, we screened previously reported mutational hotspots (exons 2-6, 8, 11, 18, 19, and 22). If no mutation was detected and samples were available, we extended our analysis to additional exons (7, 9, 10, 14, 15, 20, 21, 23, and 25). In 45 of 156 patients (28.8%), 29 mutations and 16 novel variants of unknown significance (VUS) were identified. The p.R544C mutation in exon 11 of NOTCH3 was the most frequently observed mutation (n = 8), followed by p.R75P in exon 3 (n = 7), p.R332C in exon 6 (n = 3), p.R54C in exon 2 (n = 2), and p.R90C in exon 3 (n = 2). Among the VUS, p.R1175W in exon 22, p.S414C in exon 8, and p.N1207S in exon 22 were found in 5, 3, and 2 patients, respectively. Other mutations and VUS were observed in 1 patient each. Although this was not a prospective, nationwide cohort study, the results above suggested that the spectrum of NOTCH3 mutations might be different in Koreans than in individuals of Caucasian ethnicity. Therefore, further analysis of Koreans with CADASIL might be necessary to implement a Korean-specific mutation screening paradigm.