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

Phenotypes Associated with NOTCH3 Cysteine-Sparing Mutations in Patients with Clinical Suspicion of CADASIL: A Systematic Review

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is caused by NOTCH3 mutations affecting the number of cysteines. The pathogenic role of cysteine-sparing NOTCH3 mutations with typical clinical CADASIL syndrome is still debated. This review aimed to characterize NOTCH3 cysteine-sparing mutations in patients with clinical suspicion of CADASIL. Articles on NOTCH3 cysteine-sparing mutations with clinical suspicion of CADASIL were reviewed. Clinical and radiological cerebral phenotypes data were extracted and characterized across regions and compared with phenotypes of typical CADASIL patients. We screened 298 NOTCH3 cysteine-sparing mutation individuals from 20 publications, and mutations in exon 3 were the most frequently reported (21.46%). Gait impairment (76.47%), cognitive impairment (67.47%), and stroke (62.37%) were the three most common clinical phenotypes; the most frequent radiological cerebral phenotypes were lacunes (74.29%) and cerebral microbleeds (72.73%). Compared with CADASIL patients, cognitive impairment and cerebral microbleed frequencies were significantly higher in patients with NOTCH3 cysteine-sparing mutations, while the white matter hyperintensities in anterior temporal polar and external capsule were rarely observed. Compared with Western patients, radiological phenotypes were more common than clinical phenotypes in cysteine-sparing Asian patients. More than half of cysteine-sparing patients had positive granular osmiophilic material deposits. NOTCH3 cysteine-sparing mutations in patients with clinical suspicion of CADASIL mainly manifested with gait and cognitive impairment but rare white matter hyperintensities in anterior temporal pole and external capsule. Further studies are warranted to pay attention to atypical NOTCH3 variants, which could guide specific diagnosis and help unravel underlying mechanisms.

Detecting a Novel NOTCH3 Variant in Patients with Suspected CADASIL: A Single Center Study

Introduction

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common form of familial cerebral small vessel disease in adults and is caused by NOTCH3 variants. Clinical manifestations of CADASIL include recurrent ischemic strokes, dementia, migraine or migraineous headaches, epileptic seizures, and psychiatric disorders. The clinical-radiological phenotype of the disease is also highly variable. In this study, we investigated the variability of clinical, radiological, and genetic data in patients analyzed for NOTCH3 variant in our clinic.

Methods

We performed clinical and neuropsychological examination, cerebral magnetic resonance imaging (MRI) and Doppler sonography of cerebral arteries in all patients. Next-generation sequencing test was used for detect variants in NOTCH3 gene from all CADASIL patients.

Results

By using the next-generation sequencing method, heterozygous c.380C>T pathogenic variant was detected in the 4th exon of the NOTCH3 gene in 3 patients. This is a previously unreported novel variant and resulted in the replacement of the amino acid Proline at 127th position with Leucine.

Discussion and Conclusion

The discovery of this novel pathogenic variant region may contribute to the expansion of the clinical and genetic spectrum of diseases associated with NOTCH3, leading to further research and treatment options for this disease in the future.

The relevance of the socio-emotional deficits in cerebral small vessels disease (CSVD): An exploratory study with sporadic CSVD and CADASIL patients

Background

Cerebral Small Vessels Disease (CSVD) is categorized in different forms, the most common being the sporadic form and a genetic variant - Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). Amongst the most frequent clinical manifestations are the neuropsychological changes of cognitive, behavioral, and emotional nature, whose features are still under debate.

Objective

This exploratory study aimed to compare the neuropsychological profile of a sporadic CSVD sample and a CADASIL sample with an age, education, and gender matched control group, between the ages of 30-65 YO (total sample mean age=51.16; SD=4.31).

Methods

20 patients with sporadic CSVD, 20 patients with CADASIL and 20 matched controls completed a neuropsychological assessment battery. Global cognitive state, processing speed, working memory, attention, executive dysfunction, episodic memory, social cognition, impulsivity, apathy, alexithymia, depression, and anxiety were measured. White matter hyperintensities (WMH) volume were quantified and measured as lesion burden.

Results

The cognitive differences found between the clinical groups combined (after confirming no differences between the two clinical groups) and matched controls were restricted to speed processing scores (d = 0.32 95 % CI [.12-.47]). The socio-emotional and behavioral profile revealed significantly higher levels of depression (d = 0.21, 95 % CI [.16-.33]). and anxiety (d = 0.25 95 % CI [.19-.32]) in CADASIL and sporadic CSVD groups, and the same for the alexithymia score (d = 0.533 95 % CI [.32-.65]) were the clinical groups revealed impoverished emotional processing compared to controls. WMH only significantly correlated with the cognitive changes and age.

Conclusions

In our study, CADASIL and sporadic cSVD patients combined, present multiple emotional-behavioral symptoms - alexithymia, anxiety, depression, and in a lower extent apathy and impulsivity - suggesting for the presence of emotion dysregulation behaviors, present independently of age and of the presence of cognitive deficits. Despite of the small sample size that could underpower some findings, this exploratory research supported that these symptoms may have a significant impact in disease monitoring, progression, and prognosis, requiring further investigation regarding their neurophysiological substrates.

Inflammatory Optic Neuropathy as a Presenting Feature of Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is commonly associated with early-onset stroke, migraine and vascular dementia. However, optic nerve involvement has been previously recognised. Results: We report a case of a 21-year-old female presenting with right inferior temporal scotoma, dyschromatopsia, relative pupillary afferent defect and bilateral disk oedema in the fundoscopic examination. Visual evoked potential latencies were bilaterally increased, suggesting optic neuropathy. Cerebrospinal fluid (CSF) evaluation showed 11 leukocytes, .45 mg/dL proteins, elevated IgG (4.55 mg/dL) and 2 oligoclonal bands (OCB) restricted to the CSF. ESR was 17 mm/h and CRP 5 mg/dL. Anti-Aquaporin4 anti-MOG antibodies were negative. The MRI showed right optic nerve hyperintensity, enhancing after the administration of contrast product, and multiple FLAIR focal lesions present throughout the white matter, with a noticeable confluence in the anterior temporal horns. She improved after IV high-dose methylprednisolone. Because the lesions of the white matter were highly atypical for an inflammatory disease and highly suggestive of CADASIL genetic testing was requested. A heterozygous pathogenic variant c994C>T p (Arg332Cys) in the exon 6 of the NOTCH3 gene, compatible with the diagnosis of CADASIL was found. Conclusions: This case highlights isolated optic nerve involvement as a presenting feature of CADASIL, possibly reflecting an inflammatory process associated with this hereditary vasculopathy.

Case report: Mild leukoencephalopathy caused by a new mutation of NOTCH3 gene

BACKGROUND

Cerebral autosomal dominant arteriosis with subcortical infarction and leukoencephalopathy (CADASIL) is a single-gene small-vessel disease of the brain characterized by migraine, recurrent ischemic stroke, psychiatric disorders, progressive cognitive decline, and occasional intracerebral hemorrhage.[1]NOTCH3 was identified as a pathogenic gene for CADASIL.[2] The NOTCH3 gene encodes a membrane-bound receptor protein, and to date, several different NOTCH3 gene mutations have been identified.[3] Here, we report a case of CADASIL with a heterozygous mutation c.931T > G (thymine > guanine) on the exon region of the NOTCH3 gene, resulting in an amino acid change p.C311G (cysteine > glycine).

CASE REPORT

We report a case of a female patient with CADASIL whose genetic sequencing revealed a mutation in the NOTCH3 gene. However, this patient did not exhibit any of the typical clinical findings of CADASIL but the patient's cerebral magnetic resonance imaging was consistent with the characteristic findings of CADASIL.

CONCLUSIONS

This case reminds us that mutations caused by different mutation sites present different clinical symptoms.

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.