Peripheral Blood Gene Expression Profiling Reveals Molecular Pathways Associated with Cervical Artery Dissection.

Cervical artery dissection (CeAD) is the primary cause of ischemic stroke in young adults. Monogenic heritable connective tissue diseases account for fewer than 5% of cases of CeAD. The remaining sporadic cases have known risk factors. The clinical, radiological, and histological characteristics of systemic vasculopathy and undifferentiated connective tissue dysplasia are present in up to 70% of individuals with sporadic CeAD. Genome-wide association studies identified CeAD-associated genetic variants in the non-coding genomic regions that may impact the gene transcription and RNA processing. However, global gene expression profile analysis has not yet been carried out for CeAD patients. We conducted bulk RNA sequencing and differential gene expression analysis to investigate the expression profile of protein-coding genes in the peripheral blood of 19 CeAD patients and 18 healthy volunteers. This was followed by functional annotation, heatmap clustering, reports on gene-disease associations and protein-protein interactions, as well as gene set enrichment analysis. We found potential correlations between CeAD and the dysregulation of genes linked to nucleolar stress, senescence-associated secretory phenotype, mitochondrial malfunction, and epithelial-mesenchymal plasticity.

Genetic analysis of ring finger protein 213 (RNF213) c.14576G>A polymorphism in patients with vertebral artery dissection: a comparative study with moyamoya disease.

Background: Intracranial vertebral artery dissection (VAD) and moyamoya disease (MMD) are rare cerebrovascular diseases, both of which have an ethnic predominance in the East Asian population. Disruption of the internal elastic lamina and subsequent rupture of the medial layer result in intracranial VAD. MMD is a chronic occlusive cerebrovascular disease of unknown etiology, in which the medial layer and internal elastic lamina of the intracranial arteries are significantly compromised. Recent genetic studies found ring finger protein 213 (RNF213) to be an important susceptibility gene for MMD in East Asian patients, but the association between VAD and RNF213 has not been investigated. . Methods: We investigated polymorphism of the RNF213 gene (c.14576G>A) in genomic DNA of 24 patients with intracranial VAD in comparison with 58 patients with definitive MMD and 48 healthy controls. Results: Although RNF213 gene polymorphism (c.14576G>A) was evident in 69% of the MMD patients (40/58), none of the patients with intracranial VAD had this characteristic polymorphism (0/24, p < 0.001). The incidence of RNF213 c.14576G>A polymorphism was 4.2% in healthy controls (2/48). After adjustment by age and sex, the incidence of RNF213 c.14576G>A was significantly lower in intracranial VAD patients (p = 0.021) than that in MMD patients. Conclusions: In contrast to MMD patients, the prevalence of RNF213 c.14576G>A polymorphism was significantly lower in patients with intracranial VAD. The RNF213 gene polymorphism may preferentially affect the cerebrovascular lesion in the anterior circulation, which is originated from the primitive internal carotid arteries. The genetic background underlying intracranial VAD should be elucidated in future studies. Abbreviations: VAD: vertebral artery dissection; MMD: moyamoya disease; RNF213: ring finger protein 213; CAD: carotid artery dissection.

Cervical Artery Dissection in Patients of African Ancestry.

BACKGROUND AND PURPOSE: The majority of published data in cervical artery dissection (CeAD), a common cause of stroke in young adults, derive from populations of European ancestry (EA), including a recent genome-wide study identifying an association with the rs9349379 polymorphism of the PHACTR1 gene. Little is known about CeAD in individuals of African ancestry (AA) despite robust epidemiological data showing increased risk of stroke at younger ages. We hypothesize that AA patients with CeAD have different epidemiology and clinical profiles compared to those of EA, and a different genetic architecture related to rs9349379 of the PHACTR1 gene. METHODS: We searched a single-center database of CeAD to identify AA and EA patients. We compared differential prevalence of CeAD versus all young stroke between AA and EA patients. We characterized clinical profiles via electronic medical record review. Data include descriptive statistics reported as medians or percentages. We also obtained publicly available allele frequencies of rs9349379 in AA and EA populations. RESULTS: AA patients comprise 7% of CeAD cases and 27% of young stroke cases while EA patients comprise 90% of CeAD cases and 70% of young stroke cases. Prevalence of hypertension, diabetes mellitus, and hyperlipidemia were 74, 30, and 50%, respectively, in AA patients compared to 37, 6, and 25% in EA patients. Allele frequencies for the CeAD risk allele, rs9349379(A), are higher in AA populations compared to EA populations. CONCLUSION: AA patients represent a smaller proportion of CeAD cases compared to young stroke cases at our center. AA patients suffering CeAD have higher prevalence of both vascular risk factors and frequency of the CeAD risk allele compared to EA patients. These findings suggest a complex interplay between traditional vascular risk factors and genetic predisposition underlying CeAD pathogenesis. Further prospective research is needed to clarify these associations and disparities.

Spontaneous Bilateral Cervical Internal Carotid and Vertebral Artery Dissection in a Japanese Patient without Collagen Vascular Disease with Special Reference to Single-Nucleotide Polymorphisms.

Spontaneous cervical artery dissection (sCAD) is a major cause of ischemic stroke in young adults. Frequently, sCAD involves multiple neck arteries, accounting for 13%-28% of the total sCAD cases. However, little is known about factors related to multiple sCAD. In this case, a 52-year-old man was admitted due to headache without aura. There was a personal history of migraine with aura and a family history of similar symptoms. The patient's younger brother had a left vertebral artery (VA) dissecting aneurysm and underwent endovascular occlusion of his parent artery at the age of 48. Magnetic resonance imaging of our admitted patient showed hyperintensities in the right internal carotid artery (ICA) without acute infarction, and magnetic resonance angiography revealed a narrowing of the right ICA. Angiography was then performed, which showed a trace of dissection of the left ICA and both VAs as well as the right ICA. The patient did not fulfill any major criteria of collagen vascular disease such as Ehlers-Danlos syndrome type IV or Loeys-Dietz syndrome. The data in our patient are quite similar to those reported in patients with single-nucleotide polymorphism (SNP) of PHACTR1. Obtaining the patient's informed consent, we analyzed a common SNP variation in the rs9349379[G] allele (PHACTR1), which has been reported to be associated with a lower risk of sCAD.

Common variation in PHACTR1 is associated with susceptibility to cervical artery dissection.

Cervical artery dissection (CeAD), a mural hematoma in a carotid or vertebral artery, is a major cause of ischemic stroke in young adults although relatively uncommon in the general population (incidence of 2.6/100,000 per year). Minor cervical traumas, infection, migraine and hypertension are putative risk factors, and inverse associations with obesity and hypercholesterolemia are described. No confirmed genetic susceptibility factors have been identified using candidate gene approaches. We performed genome-wide association studies (GWAS) in 1,393 CeAD cases and 14,416 controls. The rs9349379[G] allele (PHACTR1) was associated with lower CeAD risk (odds ratio (OR) = 0.75, 95% confidence interval (CI) = 0.69-0.82; P = 4.46 × 10(-10)), with confirmation in independent follow-up samples (659 CeAD cases and 2,648 controls; P = 3.91 × 10(-3); combined P = 1.00 × 10(-11)). The rs9349379[G] allele was previously shown to be associated with lower risk of migraine and increased risk of myocardial infarction. Deciphering the mechanisms underlying this pleiotropy might provide important information on the biological underpinnings of these disabling conditions.

Familial occurrence and heritable connective tissue disorders in cervical artery dissection.

OBJECTIVE: In a large series of patients with cervical artery dissection (CeAD), a major cause of ischemic stroke in young and middle-aged adults, we aimed to examine frequencies and correlates of family history of CeAD and of inherited connective tissue disorders. METHODS: We combined data from 2 large international multicenter cohorts of consecutive patients with CeAD in 23 neurologic departments participating in the CADISP-plus consortium, following a standardized protocol. Frequency of reported family history of CeAD and of inherited connective tissue disorders was assessed. Putative risk factors, baseline features, and 3-month outcome were compared between groups. RESULTS: Among 1,934 consecutive patients with CeAD, 20 patients (1.0%, 95% confidence interval: 0.6%-1.5%) from 17 families (0.9%, 0.5%-1.3%) had a family history of CeAD. Family history of CeAD was significantly more frequent in patients with carotid location of the dissection and elevated cholesterol levels. Two patients without a family history of CeAD had vascular Ehlers-Danlos syndrome with a mutation in COL3A1. This diagnosis was suspected in 2 additional patients, but COL3A1 sequencing was negative. Two patients were diagnosed with classic and hypermobile Ehlers-Danlos syndrome, one patient with Marfan syndrome, and one with osteogenesis imperfecta, based on clinical criteria only. CONCLUSIONS: In this largest series of patients with CeAD to date, family history of symptomatic CeAD was rare and inherited connective tissue disorders seemed exceptional. This finding supports the notion that CeAD is a multifactorial disease in the vast majority of cases.

[Clinical characteristics of internal carotid and vertebral arteries dissection].

OBJECTIVE: To compare demographic, clinical, and imaging characteristics of patients with internal carotid artery dissection (ICAD) and vertebral artery dissection (VAD) in a Russian population. MATERIAL AND METHODS: One hundred fifty-two consecutive patients (74 males, 49%; mean age - 37.0±10.3 years) with cervical artery dissection (ICAD - 85 patients, 56%; VA - 62 patients, 41%; ICA+VA - 5 patients - 3%) verified by MRI/MRA were studied. Five patients with both ICAD and VAD were excluded from analysis. RESULTS: Patients with ICAD more often were men (63%, p<0.0001), while patients with VAD were women (69%, p<0.0001), age distribution was similar (37.4±11.2 and 36.2±9.4 years, p>0.05). The main precipitating events for VADs were neck movements, prolonged static turning of the head, physical exertion (57% vs 28% in ICAD, p=0.0009). Head trauma within the previous month was more often reported by ICAD patients than VAD patients (21% vs 7%, p=0.0295). Clinically ICADs more frequently manifested by ischemic stroke (IS) then VADs (82% vs 55% p=0.0004), but more rarely by isolated cervical pain/headache (10% vs 35%, p<0.0001). 85% patients with dissections had neck/headache preceding cerebral ischemia: isolated neck pain (27%, p=0.0001) or a combination of neck pain with headache (55%, p=0.0004) were characteristic of VADs while headache was typical for ICADs (71%, р=0.0001). According to MRI, bilateral ICADs were found more rarely than bilateral VADs (10% vs 31% p=0.0029). Arterial occlusion was more common for ICADs (61% vs 20%, p<0.0001), double lumen was found only in VAD patients (6%, p=0.0121), and aneurysms were revealed with similar frequency (ICAD 7%, VAD 5%). CONCLUSION: There were significant differences between patients with ICAD and VAD in terms of gender distribution, precipitating events, clinical and imaging features. Different embryonic origin of ICA and VA, their anatomical differences, and intramural hematoma location in relation to intima and adventitia may underlay these differences.

Pathophysiology and risk factors of cervical artery dissection: what have we learnt from large hospital-based cohorts?

PURPOSE OF REVIEW: Cervical artery dissection (CeAD) is a major cause of ischemic stroke in young and middle-aged adults, although relatively uncommon in the community. Recent large collaborative projects have provided new insights into mechanisms and risk factors of CeAD. RECENT FINDINGS: Pathologic changes observed at the media-adventitia border in temporal arteries of CeAD patients suggest a predisposing arterial wall weakness. In large multicenter series of CeAD patients, compared to age-matched healthy controls and patients with an ischemic stroke of another cause, hypertension and migraine, especially without aura, were confirmed as risk factors for CeAD, in addition to cervical trauma and recent infection. Hypercholesterolemia and being overweight were shown to be inversely associated with CeAD. Differences in risk factor profile and structural features between carotid and vertebral dissection suggest that their pathophysiology may partly differ. An association of CeAD with fibromuscular dysplasia and reversible cerebral vasoconstriction syndrome was described. Genetic risk factors of CeAD are still poorly understood. SUMMARY: Large cohorts of CeAD patients have refined our understanding of the pathophysiology and risk factors of CeAD, but the molecular mechanisms are still poorly understood. Ongoing high-throughput genetic projects will hopefully provide novel insight into the biological substrate of CeAD.

Copy number variation in patients with cervical artery dissection.

Cervical artery dissection (CeAD) occurs in healthy young individuals and often entails ischemic stroke. Skin biopsies from most CeAD-patients show minor connective tissue alterations. We search for rare genetic deletions and duplication that may predispose to CeAD. Forty-nine non-traumatic CeAD-patients with electron microscopic (EM) alterations of their dermal connective tissue (EM+ patients) and 21 patients with normal connective tissue in skin biopsies (EM- patients) were analyzed. Affymetrix 6.0 microarrays (Affymetrix) from all patients were screened for copy number variants (CNVs). CNVs absent from 403 control subjects and from 2402 published disease-free individuals were considered as CeAD-associated. The genetic content of undentified CNVs was analyzed by means of the Gene Ontology (GO) Term Mapper to detect associations with biological processes. In 49 EM+ patients we identified 13 CeAD-associated CNVs harboring 83 protein-coding genes. In 21 EM- patients we found five CeAD-associated CNVs containing only nine genes (comparison of CNV gene density between the groups: Mann-Whitney P=0.039). Patients' CNVs were enriched for genes involved in extracellular matrix organization (COL5A2, COL3A1, SNTA1, P=0.035), collagen fibril organization COL5A2, COL3A1, (P=0.0001) and possibly for genes involved in transforming growth factor beta (TGF)-beta receptor signaling pathway (COL3A1, DUPS22, P=0.068). We conclude that rare genetic variants may contribute to the pathogenesis of CeAD, in particular in patients with a microscopic connective tissue phenotype.

Multiple strokes and bilateral carotid dissections: a fulminant case of newly diagnosed Ehlers-Danlos syndrome type IV.

Ehlers-Danlos Syndrome is a rare group of inheritable disorders resulting in abnormal collagen production, leading to skin fragility, joint hypermobility and easy bruising. Six major subtypes have been identified, of which Type IV most often leads to neurovascular complications, may lead to inner organ rupture and overall has the worst prognosis. Early recognition followed by genetic testing is key, since this diagnosis will guide decision making in the management of complications, influence the choice of antiplatelet medications versus anticoagulants and allow for potentially affected family members to be identified, undergo genetic testing and reproductive counseling. We here report the case of a 50 year old woman with a fulminant presentation of Ehlers Danlos Syndrome Type IV, including bilateral carotid and vertebral artery dissection, multiple strokes and liver rupture. Of note, this patient did not have a known history or obvious clinical features of connective tissue disease. Genetic testing confirmed the diagnosis. Review of her family history revealed multiple family members with a history of aortic dissection or aneurysm rupture. This case illustrates that Ehlers Danlos Syndrome Type IV is an important differential diagnosis even in adult patients without a known history of connective tissue disease and no prior complications.

Familial occurrence of cervical artery dissection--coincidence or sign of familial predisposition?

UNLABELLED: BACKGROUNDAND PURPOSE: The etiology of spontaneous cervical artery dissection (CeAD) is poorly understood in most patients. Mild cervical trauma preceding the dissection event is a common finding, but many CeAD occur spontaneously. It is likely that genetic factors may increase the risk for CeAD. However, familial cases are excedingly rare. Familial clustering of CeAD may be accidental or associated with genetic or environmental risk factors shared between affected relatives. In this explorative study, we aim to show that specific risk factors for familial CeAD exist. METHODS: Age of onset, sex, affected artery and number of recurrent CeAD were documented for familial patients and compared with published findings from patients with sporadic CeAD. Concordance of age, sex and dissected artery within the families was analyzed by correlation analysis and by analysis of variance or Kruskal-Wallis testing. RESULTS: The study sample consisted of 9 new patients with a family history of CeAD enrolled in the Neurology Department of the University of Heidelberg or referred to Heidelberg from other centers. The study sample also included published findings from another 23 patients, in total 32 patients. The mean age of the patients with familial CeAD at their first dissections was 38.4 ± 13.3 years. Twenty (62.5%) patients were female and 12 patients (37.5%) suffered multiple dissections. Four patients (12.5%) presented with recurrent dissections after >1 year. Patients with a familial history of CeAD were younger (p = 0.023) and presented more often with multiple dissections (p = 0.024) and recurrent dissections (p = 0.018). Age at the first event (correlation analysis p = 0.026; analysis of variance p = 0.029) and site of the dissection (correlation analysis p = 0.032; Kruskal-Wallis test p = 0.018) differed between the families, and there was no concordance of gender of affected family members (correlation analysis p = 0.500; Kruskal-Wallis test p = 0.211). CONCLUSIONS: The high prevalence of multiple dissection events and of long-term (>1 year) recurrent dissections in patients with a familial history of CeAD indicates that a specific predisposition for familial CeAD exists. Since age of onset and affected vessel differ between families, the risk profile for familial CeAD is heterogeneous. A large-scale (whole exome) sequencing analysis of 14 patients from 7 of the analyzed families is currently being performed in order to identify causative genetic variants.

MTHFR C677T, FII G20210A, FV Leiden G1691A, NOS3 intron 4 VNTR, and APOE epsilon4 gene polymorphisms are not associated with spontaneous cervical artery dissection.

AIMS: The pathogenesis of spontaneous cervical artery dissection remains unknown. We examined the association between different polymorphisms frequently found in young patients with cryptogenic stroke [methylenetetrahydrofolate reductase (MTHFR) C677T, factor II (prothrombin) G20210A, factor V G1691A (Leiden), nitric oxide synthase 3 (NOS3) intron 4 VNTR, and apolipoprotein E (APOE) epsilon4 gene] in patients with a cerebral infarct caused by spontaneous cervical artery dissection. METHODS: Forty-eight patients (27 males) and 96 matching control subjects were recruited. Clinical history, including cardiovascular risk factors, was assessed in all subjects. Genotypes were determined by a polymerase chain reaction with and without a restriction fragment length polymorphism. The genotypes and allele frequencies of the five genetic variants studied were compared between spontaneous cervical artery dissection cases and controls. We also incorporated our data into a meta-analysis of the MTHFR/C677T variant. RESULTS: Of 48 patients with spontaneous cervical artery dissection (28 vertebral and 20 carotid), the mean age of the patients was 36.6 +/- SD 9.9 years. There were no significant associations between the alleles of the five genetic polymorphisms studied and spontaneous cervical artery dissection. In the meta-analysis of the MTHFR/C677T variant, a total of 564 individuals (231 cases and 333 controls) were analysed; no significant association was observed. CONCLUSIONS: The results from this exploratory case-control study show the lack of an association between MTHFR, factor II G20210A, factor V G1691A, NOS3, intron 4 VNTR, and APOE epsilon4 gene polymorphisms and the development of spontaneous cervical artery dissection. Our findings contribute towards a better understanding of the genetic risk factors associated with spontaneous cervical artery dissection.

CADISP-genetics: an International project searching for genetic risk factors of cervical artery dissections.

BACKGROUND: Cervical artery dissection (CAD) is a frequent cause of ischemic stroke, and occasionally death, in young adults. Several lines of evidence suggest a genetic predisposition to CAD. However, previous genetic studies have been inconclusive mainly due to insufficient numbers of patients. Our hypothesis is that CAD is a multifactorial disease caused by yet largely unidentified genetic variants and environmental factors, which may interact. Our aim is to identify genetic variants associated with an increased risk of CAD and possibly gene-environment interactions. METHODS: We organized a multinational European network, Cervical Artery Dissection and Ischemic Stroke Patients (CADISP), which aims at increasing our knowledge of the pathophysiological mechanisms of this disease in a large group of patients. Within this network, we are aiming to perform a de novo genetic association analysis using both a genome-wide and a candidate gene approach. For this purpose, DNA from approximately 1100 patients with CAD, and 2000 healthy controls is being collected. In addition, detailed clinical, laboratory, diagnostic, therapeutic, and outcome data are being collected from all participants applying predefined criteria and definitions in a standardized way. We are expecting to reach the above numbers of subjects by early 2009. CONCLUSIONS: We present the strategy of a collaborative project searching for the genetic risk factors of CAD. The CADISP network will provide detailed and novel data on environmental risk factors and genetic susceptibility to CAD.

Mild hyperhomocysteinemia and low folate concentrations as risk factors for cervical arterial dissection.

BACKGROUND AND PURPOSE: Elevated homocysteine (Hcy) plasma levels are associated with an increased risk of spontaneous cervical artery dissection (sCAD). We examined the potential association between Hcy, folate, vitamin B(12) levels and 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms in patients with cerebral infarct caused by sCAD. PATIENTS AND METHODS: 39 patients who survived a cerebral infarct caused by sCAD [20 (51%) women; 24 (61.5%) vertebral and 15 (38.5%) internal carotid arteries], and 76 healthy control subjects were included. Hcy plasma levels (fasting and after methionine load), folate and vitamin B(12) levels were measured. We also performed polymorphisms of MTHFR. Hcy, vitamin B(12), folates and polymorphisms of MTHFR were assessed and any associations were analyzed using multivariate statistics. RESULTS: Mean plasma fasting Hcy level was 9.81 mumol/l for cases and 6.38 for controls (p = 0.001). The occurrence of sCAD was associated with elevated fasting Hcy levels (>95th percentile over the control group) with an adjusted odds ratio of 7.9 (95% CI 1.66-35). The association between low plasma folate values (<5th percentile) and the presence of CAD was 7.9 (95% CI 1.6-31) after adjusting for confounding variables. The distribution of the MTHFR genotype showed a higher TT mutant frequency among CAD patients (p = 0.034). CONCLUSIONS: High plasma concentrations of Hcy and low plasma levels of folate were associated with an increased risk of sCAD in the sample studied. We conclude that deficiencies in nutritional status may contribute to the relatively high incidence of CAD in Mexico.

The ICAM-1 E469K gene polymorphism is a risk factor for spontaneous cervical artery dissection.

In a primary study on proinflammatory genetic profiles in stroke, the authors found the E469K polymorphism of the intercellular adhesion molecule 1 (ICAM-1) highly represented in the subgroup with spontaneous cervical artery dissection (sCAD). They further investigated the same genetic variant in a second group of 65 patients with sCAD. An association between sCAD and EE genotype was confirmed (odds ratio 3.16; p < 0.01), indicating that a proinflammatory predisposition is a risk factor for sCAD.