NOTCH3 gene mutations in subjects clinically suspected of CADASIL

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.

CADASIL presenting as late-onset mania with anosognosia

The diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) should be considered in patients with late-onset personality change and mania. However, neuropsychological deficits precipitated by the disorder pose significant challenges to recognition and appropriate management of CADASIL in susceptible 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.

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.

Migraine genetics: current findings and future lines of research

In the last two decades, migraine research has greatly advanced our current knowledge of the genetic contributions and the pathophysiology of this common and debilitating disorder. Nonetheless, this knowledge still needs to grow further and to translate into more effective treatments. To date, several genes involved in syndromic and monogenic forms of migraine have been identified, allowing the generation of animal models which have significantly contributed to current knowledge of the mechanisms underlying these rare forms of migraine. Common forms of migraine are instead posing a greater challenge, as they may most often stem from complex interactions between multiple common genetic variants, with environmental triggers. This paper reviews our current understanding of migraine genetics, moving from syndromic and monogenic forms to oligogenic/polygenic migraines most recently addressed with some success through genome-wide association studies. Methodological issues in study design and future perspectives opened by biomarker research will also be briefly addressed.

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.

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.

Mutational screening of NOTCH3 gene reveals two novel mutations: complexity of CADASIL diagnosis

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an adult onset hereditary vascular disease with neurological manifestations. The classical clinical course is relentlessly progressive with early transient ischaemic attacks (TIA) or strokes, dementia and finally death in the mid-1960s. The disorder is inherited in an autosomal dominant fashion, with high penetrance and broad variable clinical course even within family. It is caused by mutations in the NOTCH3 gene; all causative mutations result in gain or loss of a cysteine residue within the extracellular domain, with exons 3 and 4 reported as hot spot mutational sites. Mutation analysis of the NOTCH3 gene was performed through direct sequencing of the 2-23 exons containing all EGF-like domains. Patients underwent genetic counselling pre and post testing. Here, we report two novel mutations located in exons 6 and 15 of the NOTCH3 gene; clinical description for the probands and for available relatives is enclosed. No reliable data on incidence or prevalence rates of this disease are available: it is therefore essential that the diagnosis is obtained in all suspected cases through the extensive analysis of the NOTCH3 gene and that all cases are brought to the attention of the scientific community.

Studies on the pathophysiology and genetic basis of migraine

Migraine is a neurological disorder that affects the central nervous system causing painful attacks of headache. A genetic vulnerability and exposure to environmental triggers can influence the migraine phenotype. Migraine interferes in many facets of people's daily life including employment commitments and their ability to look after their families resulting in a reduced quality of life. Identification of the biological processes that underlie this relatively common affliction has been difficult because migraine does not have any clearly identifiable pathology or structural lesion detectable by current medical technology. Theories to explain the symptoms of migraine have focused on the physiological mechanisms involved in the various phases of headache and include the vascular and neurogenic theories. In relation to migraine pathophysiology the trigeminovascular system and cortical spreading depression have also been implicated with supporting evidence from imaging studies and animal models. The objective of current research is to better understand the pathways and mechanisms involved in causing pain and headache to be able to target interventions. The genetic component of migraine has been teased apart using linkage studies and both candidate gene and genome-wide association studies, in family and case-control cohorts. Genomic regions that increase individual risk to migraine have been identified in neurological, vascular and hormonal pathways. This review discusses knowledge of the pathophysiology and genetic basis of migraine with the latest scientific evidence from genetic studies.