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

Neglected Mendelian causes of stroke in adult Chinese patients who had an ischaemic stroke or transient ischaemic attack

BACKGROUND AND PURPOSE

Multiple factors play important roles in the occurrence and prognosis of stroke. However, the roles of monogenic variants in all-cause ischaemic stroke have not been systematically investigated. We aim to identify underdiagnosed monogenic stroke in an adult ischaemic stroke/transient ischaemic attack (TIA) cohort (the Third China National Stroke Registry, CNSR-III).

METHODS

Targeted next-generation sequencing for 181 genes associated with stroke was conducted on DNA samples from 10 428 patients recruited through CNSR-III. The genetic and clinical data from electronic health records (EHRs) were reviewed for completion of the diagnostic process. We assessed the percentages of individuals with pathogenic or likely pathogenic (P/LP) variants, and the diagnostic yield of pathogenic variants in known monogenic disease genes with associated phenotypes.

RESULTS

In total, 1953 individuals harboured at least one P/LP variant out of 10 428 patients. Then, 792 (7.6%) individuals (comprising 759 individuals harbouring one P/LP variant in one gene, 29 individuals harbouring two or more P/LP variants in different genes and 4 individuals with two P/LP variants in ABCC6) were predicted to be at risk for one or more monogenic diseases based on the inheritance pattern. Finally, 230 of 792 individuals manifested a clinical phenotype in the EHR data to support the diagnosis of stroke with a monogenic cause. The most diagnosed Mendelian cause of stroke in the cohort was cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. There were no relationships between age or family history and the incidence of first symptomatic monogenic stroke in patients.

CONCLUSION

The rate of monogenic cause of stroke was 2.2% after reviewing the clinical phenotype. Possible reasons that Mendelian causes of stroke may be missed in adult patients who had an ischaemic stroke/TIA include a late onset of stroke symptoms, combination with common vascular risks and the absence of a prominent family history.

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.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with multiple different onset forms of frequent recurrent attacks: A case report and literature review

INTRODUCTION

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is one kind of monogenic hereditary small-vessel disease in the brain caused by mutations in the NOTCH3 gene. However, it is rare for CADASIL to recur with different clinical manifestations in 1 patient, and some atypical clinical manifestations can easily lead to misdiagnosis by clinical physicians.

CASE CONCERN

A 34-year-old male presented with transient speech disorder accompanied by weakness in the left side of the body for 1 day in June 2020. Magnetic resonance imaging showed acute ischemic infarction in right centrum semiovale, along with multiple abnormal white matter hyperintensities in the brain. Genetic sequencing identified a heterozygous mutation in the NOTCH3 gene. The patient experienced recurrent episodes in 2021 and 2023, with varying clinical symptoms including visual blurring, abnormal limb sensation, and sudden cognitive dysfunction.

DIAGNOSIS

The diagnoses of CADASIL is based on clinical manifestations, imaging results, and genetic reports.

INTERVISION AND OUTCOMES

The patient was received symptomatic treatment including antiplatelet aggregation therapy, lipid regulation, and plaque stabilization, resulting in improved symptoms.

OUTCOMES

During the course of the disease, after medication treatment and rehabilitation exercise, the patient clinical symptoms have significantly improved. Currently, the patient is closely following up and regularly undergoing relevant examinations.

LESSONS

In this rare case, we found that CADASIL can recur multiple times in a patient with different clinical symptoms, which can easily lead to clinical misdiagnosis. Clinicians should consider the possibility of CADASIL in young patients with sudden typical neurological dysfunction.

Correction of a CADASIL point mutation using adenine base editors in hiPSCs and blood vessel organoids

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic small vessel disease caused by mutations in the NOTCH3 gene. However, the pathogenesis of CADASIL remains unclear, and patients have limited treatment options. Here, we use human induced pluripotent stem cells (hiPSCs) generated from the peripheral blood mononuclear cells of a patient with CADASIL carrying a heterozygous NOTCH3 mutation (c.1261C>T, p.R421C) to develop a disease model. The correction efficiency of different adenine base editors (ABEs) is tested using the HEK293T-NOTCH3 reporter cell line. ABEmax is selected based on its higher efficiency and minimization of predicted off-target effects. Vascular smooth muscle cells (VSMCs) differentiated from CADASIL hiPSCs show NOTCH3 deposition and abnormal actin cytoskeleton structure, and the abnormalities are recovered in corrected hiPSC-derived VSMCs. Furthermore, CADASIL blood vessel organoids generated for in vivo modeling show altered expression of genes related to disease phenotypes, including the downregulation of cell adhesion, extracellular matrix organization, and vessel development. The dual adeno-associated virus (AAV) split-ABEmax system is applied to the genome editing of vascular organoids with an average editing efficiency of 8.82%. Collectively, we present potential genetic therapeutic strategies for patients with CADASIL using blood vessel organoids and the dual AAV split-ABEmax system.

Contribution of the APOE Genotype to Cognitive Impairment in Individuals With NOTCH3 Cysteine-Altering Variants

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most prevalent monogenic cerebral small-vessel disease. Phenotype variability in CADASIL suggests the possible role of genetic modifiers. We aimed to investigate the contributions of the APOE genotype and Neurogenic locus notch homolog protein 3 (NOTCH3) variant position to cognitive impairment associated with CADASIL.

METHODS AND RESULTS

Patients with the cysteine-altering NOTCH3 variant were enrolled in a cross-sectional study, including the Mini-Mental State Examination (MMSE), brain magnetic resonance imaging, and APOE genotyping. Cognitive impairment was defined as an MMSE score <24. The associations between the MMSE score and genetic factors were assessed using linear regression models. Bayesian adjustment for confounding was used to identify clinical confounders. A total of 246 individuals were enrolled, among whom 210 (85%) harbored the p.R544C variant, 96 (39%) had cognitive impairment, and 150 (61%) had a history of stroke. The APOE ɛ2 allele was associated with a lower MMSE score (adjusted B, -4.090 [95% CI, -6.708 to -1.473]; P=0.023), whereas the NOTCH3 p.R544C variant was associated with a higher MMSE score (adjusted B, 2.854 [95% CI, 0.603-5.105]; P=0.0132) after adjustment for age, education, and history of ischemic stroke. Mediation analysis suggests that the associations between the APOE ɛ2 allele and MMSE score and between the NOTCH3 p.R544C variant and MMSE score are mediated by mesial temporal atrophy and white matter hyperintensity, respectively.

CONCLUSIONS

APOE genotype may modify cognitive impairment in CADASIL, whereby individuals carrying the APOE ɛ2 allele may present a more severe cognitive impairment.

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 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.

Three-tiered EGFr domain risk stratification for individualized NOTCH3-small vessel disease prediction

Cysteine-altering missense variants (NOTCH3cys) in one of the 34 epidermal growth-factor-like repeat (EGFr) domains of the NOTCH3 protein are the cause of NOTCH3-associated small vessel disease (NOTCH3-SVD). NOTCH3-SVD is highly variable, ranging from cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) at the severe end of the spectrum to non-penetrance. The strongest known NOTCH3-SVD modifier is NOTCH3cys variant position: NOTCH3cys variants located in EGFr domains 1-6 are associated with a more severe phenotype than NOTCH3cys variants located in EGFr domains 7-34. The objective of this study was to further improve NOTCH3-SVD genotype-based risk prediction by using relative differences in NOTCH3cys variant frequencies between large CADASIL and population cohorts as a starting point. Scientific CADASIL literature, cohorts and population databases were queried for NOTCH3cys variants. For each EGFr domain, the relative difference in NOTCH3cys variant frequency (NVFOR) was calculated using genotypes of 2574 CADASIL patients and 1647 individuals from population databases. Based on NVFOR cut-off values, EGFr domains were classified as either low (LR-EGFr), medium (MR-EGFr) or high risk (HR-EGFr). The clinical relevance of this new three-tiered EGFr risk classification was cross-sectionally validated by comparing SVD imaging markers and clinical outcomes between EGFr risk categories using a genotype-phenotype data set of 434 CADASIL patients and 1003 NOTCH3cys positive community-dwelling individuals. CADASIL patients and community-dwelling individuals harboured 379 unique NOTCH3cys variants. Nine EGFr domains were classified as an HR-EGFr, which included EGFr domains 1-6, but additionally also EGFr domains 8, 11 and 26. Ten EGFr domains were classified as MR-EGFr and 11 as LR-EGFr. In the population genotype-phenotype data set, HR-EGFr individuals had the highest risk of stroke [odds ratio (OR) = 10.81, 95% confidence interval (CI): 5.46-21.37], followed by MR-EGFr individuals (OR = 1.81, 95% CI: 0.84-3.88) and LR-EGFr individuals (OR = 1 [reference]). MR-EGFr individuals had a significantly higher normalized white matter hyperintensity volume (nWMHv; P = 0.005) and peak width of skeletonized mean diffusivity (PSMD; P = 0.035) than LR-EGFr individuals. In the CADASIL genotype-phenotype data set, HR-EGFr domains 8, 11 and 26 patients had a significantly higher risk of stroke (P = 0.002), disability (P = 0.041), nWMHv (P = 1.8 × 10-8), PSMD (P = 2.6 × 10-8) and lacune volume (P = 0.006) than MR-EGFr patients. SVD imaging marker load and clinical outcomes were similar between HR-EGFr 1-6 patients and HR-EGFr 8, 11 and 26 patients. NVFOR was significantly associated with vascular NOTCH3 aggregation load (P = 0.006), but not with NOTCH3 signalling activity (P = 0.88). In conclusion, we identified three clinically distinct NOTCH3-SVD EGFr risk categories based on NFVOR cut-off values, and identified three additional HR-EGFr domains located outside of EGFr domains 1-6. This EGFr risk classification will provide an important key to individualized NOTCH3-SVD disease prediction.

Update on the Epidemiology, Pathogenesis, and Biomarkers of Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic disorder of the cerebral small blood vessels. It is caused by mutations in the NOTCH3 gene on chromosome 19, and more than 280 distinct pathogenic mutations have been reported to date. CADASIL was once considered a very rare disease with an estimated prevalence of 1.3-4.1 per 100,000 adults. However, recent large-scale genomic studies have revealed a high prevalence of pathogenic NOTCH3 variants among the general population, with the highest risk being among Asians. The disease severity and age at onset vary significantly even among individuals who carry the same NOTCH3 mutations. It is still unclear whether a significant genotype-phenotype correlation is present in CADASIL. The accumulation of granular osmiophilic material in the vasculature is a characteristic feature of CADASIL. However, the exact pathogenesis of CADASIL remains largely unclear despite various laboratory and clinical observations being made. Major hypotheses proposed so far have included aberrant NOTCH3 signaling, toxic aggregation, and abnormal matrisomes. Several characteristic features have been observed in the brain magnetic resonance images of patients with CADASIL, including subcortical lacunar lesions and white matter hyperintensities in the anterior temporal lobe or external capsule, which were useful in differentiating CADASIL from sporadic stroke in patients. The number of lacunes and the degree of brain atrophy were useful in predicting the clinical outcomes of patients with CADASIL. Several promising blood biomarkers have also recently been discovered for CADASIL, which require further research for validation.

Phenotypic variability in 446 CADASIL patients: Impact of NOTCH3 gene mutation location in addition to the effects of age, sex and vascular risk factors

The recent discovery that the prevalence of cysteine mutations in the NOTCH3 gene responsible for CADASIL was more than 100 times higher in the general population than that estimated in patients highlighted that the mutation location in EGFr-like-domains of the NOTCH3 receptor could have a major effect on the phenotype of the disease. The exact impact of such mutations locations on the multiple facets of the disease has not been fully evaluated. We aimed to describe the phenotypic spectrum of a large population of CADASIL patients and to investigate how this mutation location influenced various clinical and imaging features of the disease. Both a supervised and a non-supervised approach were used for analysis. The results confirmed that the mutation location is strongly related to clinical severity and showed that this effect is mainly driven by a different development of the most damaging ischemic tissue lesions at cerebral level. These effects were detected in addition to those of aging, male sex, hypertension and hypercholesterolemia. The exact mechanisms relating the location of mutations along the NOTCH3 receptor, the amount or properties of the resulting NOTCH3 products accumulating in the vessel wall, and their final consequences at cerebral level remain to be determined.

Clinical features and spectrum of NOTCH3 variants in Finnish patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

OBJECTIVES

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a cerebral small vessel disease caused by pathogenic variants in the NOTCH3 gene. In Finland, the majority of CADASIL patients carry the pathogenic founder variant c.397C>T, (p.Arg133Cys), but the spectrum of other NOTCH3 variants has not been investigated previously. The aim of the study was to investigate the spectrum and prevalence of NOTCH3 variants Finnish CADASIL patients and to examine the clinical features associated with them.

MATERIALS AND METHODS

The spectrum of NOTCH3 variants and the clinical features associated with them were retrospectively examined in 294 Finnish CADASIL patients tested during January 1996 to October 2021 in the Medical Genetics laboratory of Department of Genomics of Turku University Hospital, where practically all samples of patients with suspected CADASIL in Finland are investigated.

RESULTS

The most common NOTCH3 variants in the study cohort were c.397C>T, (p.Arg133Cys) (68%) and c.3206A>G p.(Tyr1069Cys) (18%), but other less common NOTCH3 variants were detected in as many as 14% of the patients. Eight of the detected NOTCH3 variants were novel: c.520T>A,p.(Cys174Ser), c.836A>G,p.(Gln279Arg), c.1369T>G,p.(Cys457Gly), c.1338C>G,p.(Cys446Trp), c.1564T>G,p.(Cys522Gly), c.2848T>G,p.(Cys950Gly), c.6102dup,p.(Gly2035Argfs*60), and c.2410+6C>G. Other NOTCH3 variants than p.Arg133Cys and p.Tyr1069Cys were more often associated with more severe clinical features.

CONCLUSION

This study revealed the genetic and clinical spectrum of CADASIL in the Finnish population. Sequencing of the whole NOTCH3 gene performing a gene-panel or exome sequencing is recommended when suspecting CADASIL.

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.

Genetic spectrum of NOTCH3 and clinical phenotype of CADASIL patients in different populations

Introduction

Cerebral autosomal‐dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a relatively common cerebral small vessel disease. NOTCH3 has been identified as the causative gene of CADASIL. Clinical variability and genetic heterogeneity were observed in CADASIL patients and need to be further clarified.

Aims

The aim of the study was to clarify genetic spectrum of NOTCH3 and clinical phenotype of CADASIL patients.

Methods

Suspected CADASIL patients were collected by our center between 2016 and 2021. Whole exome sequencing was performed to screen NOTCH3 mutations of these patients. Genetic and clinical data of CADASIL patients from previous studies were also analyzed. Studies between 1998 and 2021 that reported more than 9 pedigrees with detailed genetic data or clinical data were included. After excluding patients carrying cysteine‐sparing mutations, genetic data of 855 Asian pedigrees (433 Chinese; 226 Japanese, and 196 Korean) and 546 Caucasian pedigrees, in a total of 1401 CADASIL pedigrees were involved in mapping mutation spectrum. Clinical data of 901 Asian patients (476 Chinese patients, 217 Japanese patients, and 208 Korean patients) and 720 Caucasian patients, in a total of 1621 patients were analyzed and compared between different populations.

Results

Two novel mutations (c.400T>C, p.Cys134Arg; c.1511G>A, p.Cys504Tyr) and 24 known cysteine‐affecting variants were identified in 36 pedigrees. Genetic spectrums of Asians (Chinese, Japanese, and Korean) and Caucasians were clarified, p.R544C and p.R607C were the most common mutations in Asians while p.R1006C and p.R141C in Caucasians. For clinical features, Asians were more likely to develop symptoms of TIA or ischemic stroke (p < 0.0001) and cognitive impairment (p < 0.0001). Nevertheless, Caucasians had a higher tendency to present migraine (p < 0.0001) and psychiatric disturbance (p < 0.0001). The involvement of temporal pole was more likely to happen in Caucasians (p < 0.0001).

Conclusion

The findings help to better understand the clinical variability and genetic heterogeneity of CADASIL.

Mutation screening and association analysis of NOTCH3 p.R544C in patients with migraine with or without aura

BACKGROUND

The role of the NOTCH3 p.R544C variant, the predominant variant of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy in multiple East Asian regions, in migraine is unknown.

METHODS

Migraine patients (n = 2,884) (2,279F/605M, mean age 38.8 ± 11.7 years), including 324 (11.2%) with migraine with aura, were prospectively enrolled by headache specialists according to the International Classification of Headache Disorders criteria. These patients and 3,502 population controls free of stroke, dementia, and headache were genotyped for NOTCH3 p.R544C by TaqMan genotyping assay or Axiom Genome-Wide TWB 2.0 Array. Clinical manifestations and brain magnetic resonance images were examined and compared between migraine patients with and without NOTCH3 p.R544C.

RESULTS

Thirty-two migraine patients (1.1%) and 36 controls (1.0%) harbored the p.R544C variant, and the percentages were comparable among migraine patients without and with aura, and controls (1.2%, vs. 0.6% vs. 1.0%, p = 0.625). Overall, migraine patients with and without the p.R544C variant had similar percentages of migraine with aura, headache characteristics, frequencies and disabilities. However, those with p.R544C were less likely to have pulsatile headaches (50.0% vs. 68.2%, p = 0.028), and more likely to have moderate to severe white matter hyperintensities in the external capsule (18.8% vs. 1.2%, p = 0.006) and anterior temporal lobe (12.5% vs. 0%, p = 0.008).

CONCLUSIONS

Our findings suggest that NOTCH3 p.R544C does not increase the risk of migraine with aura, or migraine as a whole, and generally does not alter clinical manifestations of migraine. The role of NOTCH3 variants, as well as potential influences from ethnicity or modifier genes, in migraine needs to be further clarified.

Cognition, mood and behavior in CADASIL

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CADASIL is responsible for cognitive, mood or behavior disturbances.

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Cognitive disturbances range from moderate cognitive slowing to impairment of executive functions and may progress to a global decrease of cognitive efficiency up to severe dementia.

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Mood disturbances are extremely variable in intensity, depression is the most frequent symptom.

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Behavioral changes may occur at all stage of the disease, but are often associated with the onset of cognitive alterations. Apathy is the most prominent behavior alteration.

CADASIL is the most common familial cerebral small vessel disease (cSVD). Stereotyped mutations of the NOTCH3 gene are responsible for this archetypal ischemic cSVD that can lead, at the very end stage, to severe dementia. Variable cognitive alterations, mood, or behavior disturbances are frequently observed during the course of the disease. In this review, these clinical manifestations, their occurrence, severity and duration are analyzed in relation to the disease progression. Also, the potential relationships with cerebral lesions and treatment options are discussed.

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 case of CADASIL caused by NOTCH3 c.512_605delinsA heterozygous mutation

BACKGROUND

Autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a cerebrovascular disease closely related to the NOTCH3 gene. More than 200 mutations in this gene have been reported to be associated with this disease.

METHODS

The NOTCH3 gene from CADASIL patient was screened for mutations by whole-exome sequencing (WES). PCR amplification and direct Sanger sequencing were used to verify the suspicious gene mutation sites detected by WES.

RESULTS

We performed second-generation sequencing on a sample of the patient's genome and found a heterozygous deletion-insertion mutation c.512_605delinsA in exon 4 of NOTCH3, which resulted in amino acid changes p.G171_A202delinsE. This variation was confirmed by the direct Sanger sequencing. It may be rated as a CADASIL clinical variation.

CONCLUSION

Discovery of this mutation site provides an important theoretical basis for specific gene-based diagnosis and treatment of CADASIL.

NOTCH3 Variants and Genotype-Phenotype Features in Chinese CADASIL Patients

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a cerebral small vessel disease caused by mutations in the NOTCH3 gene. Archetypal disease-causing mutations are cysteine-affecting variants within the 34 epidermal growth factor-like repeat (EGFr) region of the Notch3 extracellular subunit. Cysteine-sparing variants and variants outside the EGFr coding region associated with CADASIL phenotype have been reported. However, the linkage between untypical variants and CADASIL is unclear. In this study, we investigated the spectrum of NOTCH3 variants in a cohort of 38 probands from unrelated families diagnosed as CADASIL. All coding exons of the NOTCH3 gene were analyzed, and clinical data were retrospectively studied. We identified 23 different NOTCH3 variants including 14 cysteine-affecting pathogenic variants, five cysteine-sparing pathogenic variants, two reported cysteine-sparing variants of unknown significance (VUS), and two novel VUS outside EGFr region. In retrospective studies of clinical data, we found that patients carrying cysteine-sparing pathogenic variants showed later symptom onset (51.36 ± 7.06 vs. 44.96 ± 8.82, p = 0.023) and milder temporal lobe involvement (1.50 ± 1.74 vs. 3.11 ± 2.32, p = 0.027) than patients carrying cysteine-affecting pathogenic variants. Our findings suggested that untypical variants comprise a significant part of NOTCH3 variants and may be associated with a distinctive phenotype.

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.

The role of NOTCH3 variants in Alzheimer's disease and subcortical vascular dementia in the Chinese population

AIMS

NOTCH3 gene mutations predominantly cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, a common etiology of subcortical vascular dementia (SVaD). Besides, there may be a pathogenic link between NOTCH3 variants and Alzheimer's disease (AD). We aimed to study the role of NOTCH3 variants in AD and SVaD patients.

METHODS

We recruited 763 patients with dementia (667 AD and 96 SVaD) and 365 healthy controls from the Southern Han Chinese population. Targeted capture sequencing was performed on NOTCH3 coding and adjacent intron regions to detect the pathogenic variants in AD and SVaD. The relationship between common or rare NOTCH3 variants and AD was further analyzed using Plink1.9.

RESULTS

Five known pathogenic variants (p.R182C, p.C201S, p.R544C, p.R607C, and p.R1006C) and two novel likely pathogenic variants (p.C201F and p.C1061F) were detected in 16 SVaD patients. Additionally, no pathogenic or likely pathogenic variants were found in AD patients. NOTCH3 was not associated with AD in either single-variant association analysis or gene-based association analysis.

CONCLUSION

Our findings broaden the mutational spectrum of NOTCH3 and validate the pathogenic role of NOTCH3 mutations in SVaD, but do not support the notion that NOTCH3 variation influences the risk of AD.

Genetic and nongenetic factors associated with CADASIL: A retrospective cohort study

OBJECTIVE

To explore the role of cardiovascular risk factors and the different NOTCH-3 mutations to explain the variability observed in the clinical presentation of CADASIL.

METHODS

This was a retrospective cohort study of 331 individuals, 90 were carriers of four mutations in the NOTCH3 gene. These four mutations are the ones identified in our region from the genetic evaluation of probands. Cox proportional hazards models were fitted to estimate the effect of genetic and cardiovascular factors on the onset of migraine, first stroke, and dementia. Competing risk regression models considered death as risk.

RESULTS

Noncarriers (healthy controls from the same families without NOTCH3 mutations) and NOTCH3 mutation carriers had similar frequencies for all cardiovascular risk factors. Diabetes (SHR 2.74, 95% CI 1.52-4.94) was associated with a younger age at onset of strokes among carriers. Additionally, a genotype-phenotype relationship was observed among C455R mutation carriers, with higher frequency of migraines (100%), younger age at onset of migraine (median age 7 years, IQR 8) and strokes (median age 30.5 years, IQR 26). Moreover, fewer carriers of the R141C mutation exhibited migraines (20%), and it was even lower than the frequency observed in the noncarrier group (44.8%).

CONCLUSIONS

This study characterizes extended family groups, allowing us a comparison in the genotype-phenotype. The results suggest a complex interplay of genetic and cardiovascular risk factors that may help explain the variability in the clinical presentation and severity of CADASIL.

Cysteine-Altering NOTCH3 Variants Are a Risk Factor for Stroke in the Elderly Population

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Cysteine altering NOTCH3 variants, which have previously been exclusively associated with the rare hereditary small vessel disease cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, have a population frequency of 1:300 worldwide. Using a large population database, and taking genotype as a starting point, we aimed to determine whether individuals harboring a NOTCH3 cysteine altering variant have a higher load of small vessel disease markers on brain magnetic resonance imaging than controls, as well as a higher risk of stroke and cognitive impairment.

Imaging-based pregenetic screening for NOTCH3 p.R544C mutation in ischemic stroke in Taiwan

Objective

To develop an easily applicable screening score to guide NOTCH3 p.R544C genetic testing for patients who presented with acute ischemic cerebrovascular events in Taiwan.

Methods

1734 patients who presented with ischemic cerebrovascular events were enrolled from the Formosa Stroke Genetic Consortium stroke registry and were screened for the NOTCH3 p.R544C mutation. Clinical and MRI characteristics of NOTCH3 p.R544C mutation carriers (n = 36) and a subset of noncarriers (n = 673) were tested in a logistic regression model to identify key features associated with the NOTCH3 p.R544C carrier status. Variables and their odds ratios in the regression model were used to develop the R544C screening score to predict positive NOTCH3 p.R544C test results.

Results

We constructed the R544C screening score using five clinical and imaging characteristics, including stroke onset before 50 years of age, the small vessel occlusion subtype, a family history of stroke/TIA in siblings, external capsule involvement, and advanced deep white matter hyperintensity. The area under the ROC curve of the screening score was 0.867 (95% CI = 0.810‐0.924). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 0.75, 0.88, 0.13, 0.99, and 0.88, respectively, for a cutoff score of 5 points. In addition, the R544C screening score was validated in another cohort composed of 235 stroke patients with comparable performance (area under the ROC curve = 0.957, 95% CI = 0.916‐0.997).

Interpretations

For Taiwanese patients presenting with acute ischemic cerebrovascular events, the R544C screening score is easily applicable and can efficiently select high‐risk patients for NOTCH3 p.R544C mutation test.

Homozygous NOTCH3 p.R587C mutation in Chinese patients with CADASIL: a case report

Background

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small vessel disease caused by mutations in NOTCH3 gene with remarkable phenotypic heterogeneity. Cases of CADASIL associated with homozygous NOTCH3 mutations are rare and subsequently understudied. In this study, we investigate the genetic and phenotypic features within patients of CADASIL with homozygous NOTCH3 mutations.

Case presentation

We recruited two affected individuals with CADASIL from a mainland Chinese family. The proband (Patient 1), a 60-year-old male, presented with slow progressive gait instability, severe cognitive impairment, and emotional disorder for more than 2 years with a history of ischemic stroke and hypertension. His younger brother (Patient 2) presented with apparent gait difficulties, dysarthria as well as cognitive decline at 59 years old. Brain magnetic resonance imaging (MRI) showed diffused white matter lesions involving bilateral periventricular white matter, semioval center region, and anterior temporal lobes. Molecular genetic testing identified a homozygous variant, c.1759C > T (p.R587C), in NOTCH3 gene in both patients. Pathological analysis revealed granular osmiophilic material (GOM) deposits in small arterial walls of skin from the proband. The diagnosis of CADASIL was confirmed.

Conclusions

Our cases of CADASIL with homozygous mutation c.1759C > T (p.R587C) in NOTCH3 share similar manifestation to the patients with heterozygous same mutation reported previously. Other than genetic factors, vascular risk factors or environmental factors might contribute to the phenotypic variation of CADASIL.

New clinical characteristics and novel pathogenic variants of patients with hereditary leukodystrophies

Aim

Leukodystrophies are a group of inherited white matter disorders with clinical, genetic, and imaging heterogeneity, which usually pose a diagnostic challenge for physicians. We aimed to identify new clinical characteristics and novel pathogenic variants of hereditary leukodystrophies in this study.

Methods

Whole exome sequencing (WES) was performed in 28 unrelated patients clinically suspected with leukodystrophies. Leukocytes enzyme activity test, electroencephalogram (EEG), electromyography (EMG), and brain MRI were conducted. Functional analysis was performed, and the pathogenicity of variants was classified according to the American College of Medical Genetics and Genomics (ACMG) standards and guidelines.

Results

We made definite diagnosis in 8 probands with 12 pathogenic variants and reported new clinical characteristics and imaging features of these patients. Three novel pathogenic variants were identified, including a microdeletion variant c.2654_2654+3del within CSF1R, a nonsense variant c.1321C>T, and a missense variant c.166G>C within GALC.

Conclusion

Our results have deepened the understanding of clinical, genetic, and imaging heterogeneity of hereditary leukodystrophies, and expanded the spectrum of pathogenic variants and clinical features.

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.

A novel cysteine-sparing G73A mutation of NOTCH3 in a Chinese CADASIL family

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic disease leading to stroke and vascular dementia. CADASIL is an inherited small blood vessel disease caused by mutations in the gene encoding the neurogenic locus notch homolog protein 3 (NOTCH3). NOTCH3 is large type I membrane receptor mainly expressed in vascular smooth muscle cells and pericytes. Most identified mutations result in insert or deletion of a cysteine residue within the EGF-like repeats. To date, some cases with a cysteine-sparing mutant have been described. Genetic analysis revealed a novel mutation in NOTCH3 in a CADASIL family. Molecular analysis revealed its potential pathogenic mechanism in causing CADASIL. In this paper, we present a Chinese family with a novel cysteine-sparing mutation in exon 3 (c.218G>C, p.G73A) of the NOTCH3 gene. Family carriers of the same mutation presented with symptoms and imaging abnormalities characteristic of CADASIL. The location of glycine 73 in between C5-C6 disulfide bond of EGF-like domain 1 shows high conservation from humans to zebra fish. It has previously been suggested that the aggregate-prone property of mutant NOTCH3 contributes to a cytotoxic effect in the pathogenic mechanism underlying CADASIL. Here, we investigated the pathogenic mechanism of the new mutation in vitro using HEK293 cells transfected with either a wild-type (WT) or c.218G>C (p.G73A) NOTCH3^ECD plasmids, and we found p.G73A NOTCH3^ECD was more prone to form aggregation and resistant to degradation. Moreover, the p.G73A NOTCH3^ECD compromised cell viability by promoting apoptosis. Two known CADASIL mutants R133C and R75P showed similar results with G73A mutants. Our study here identified G73A as a new mutation in NOTCH3 to cause CADASIL and revealed that the G73A mutation and two known mutants R75P and R133C decreased NOTCH3 protein turnover and induced cell death.

Reduced Venous Oxygen Saturation Associates With Increased Dependence of Patients With Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy: A 7.0-T Magnetic Resonance Imaging Study

Background and Purpose- Accumulating evidence has demonstrated hemodynamic abnormalities and cerebral hypoperfusion in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Increased venous susceptibility assessed by susceptibility weighted imaging and mapping has been shown to indicate a decrease in venous oxygen saturation. This study aimed to investigate whether altered venous oxygen saturation is related to clinical phenotypes of CADASIL patients. Methods- Using 7.0-T susceptibility weighted imaging and mapping, we compared venous susceptibility of cortical veins between 41 CADASIL patients and 43 age- and sex-matched healthy controls. The magnetic resonance imaging lesion load, mini-mental state examination score, Barthel Index, and modified Rankin Scale were examined in the patient group, and the correlations between venous susceptibility and clinical characteristics were analyzed. Results- Venous susceptibility increased with age (r=0.508, P=0.001) and was higher in CADASIL patients than in healthy controls (t=-4.673; P<0.001). We found a positive association between venous susceptibility and the age-related white matter change scores (r=0.364; P=0.019), number of lacunar infarctions (r=0.520; P<0.001), number of cerebral microbleeds (ρ=0.445; P=0.004), and small-vessel disease scores (ρ=0.465; P=0.002) in CADASIL patients. Moreover, increased venous susceptibility was associated with higher modified Rankin Scale scores in CADASIL patients after adjustment for age- and small-vessel disease scores (odds ratio=3.178; 95% CI, 1.101-9.179; P=0.033). Conclusions- Our findings indicate that extensive cerebral hypoperfusion may induce central nervous system impairment in CADASIL, and susceptibility weighted imaging and mapping could be used clinically to assess the condition of CADASIL patients.

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.

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.

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.