The role of type III collagen in spontaneous cervical arterial dissections

Long-Term Course of Circulating Elastin, Collagen Type I, and Collagen Type III in Patients with Spontaneous Cervical Artery Dissection: a Prospective Multicenter Study

An impaired integrity of vascular elements and the extracellular matrix (ECM) has been discussed to play a critical role in the pathophysiology of spontaneous cervical artery dissection (sCAD). This study aimed to explore the temporal course of circulating elastin, collagen type I, and collagen type III in patients with sCAD and evaluated their eligibility as diagnostic biomarkers. Patients with sCAD were prospectively enrolled in four German stroke centers. Blood samples were collected at baseline (acute phase), at day 10 ± 3 (subacute phase), and after 6 ± 1 months (chronic phase). Patients with acute ischemic stroke not related to sCAD, healthy probands, and patients undergoing thromboendarterectomy of the carotid artery served as control groups. Serum levels of elastin and collagen types I and III were determined by ELISAs. Fifty-seven patients with sCAD were enrolled. Compared to all three control groups, patients with sCAD had significantly lower levels of elastin and collagen type III at baseline and after 6 months. Compared to healthy probands, patients with sCAD showed similar collagen type I levels at baseline and in the subacute phase, but significantly increased levels after 6 months. As serum levels of elastin, collagen types I and III were not elevated in the acute phase, they do not appear eligible as biomarkers for the diagnosis of sCAD. Persisting low serum levels of elastin and collagen type III towards the chronic phase of sCAD strengthens the hypothesis of a subtle, in most cases clinically inapparent affection of the ECM in patients with sCAD.

Spontaneous cervical artery dissection: is it really a connective tissue disease? A comprehensive review

Background

Spontaneous cervical artery dissection (sCeAD) is an important cause of stroke in young adults. The underlying pathophysiology remains unclear, without validated biomarkers to identify subjects at risk. Previous studies suggested the role of abnormalities in the connective component of the arterial wall.

Purpose

To assess dermal ultrastructural aberrations of connective tissue by skin biopsy and genetic variations in sCeAD patients.

Method

We searched the PubMed and Scopus databases until August 2023 with PRISMA guidelines. Original articles assessing skin biopsy in sCeAD patients were included. Two reviewers independently conducted the screening.

Findings

We included 16 studies compromising 459 patients. Thirteen studies assessed ultrastructural changes and found aberrations of collagen and elastic fibers, described as irregular contours and calibers of collagen fibrils, composite flower-like fibrils, fragmented moth-eaten elastin, and microcalcifications, cumulatively in 50.5% of patients. Seven studies showed no causative mutations in collagen type I, III, V, or elastin genes. One study showed linkage between connective tissue alterations and mutation on chromosomes 15q2 and 10q26 using genome-wide linkage analysis, while another study found significant copy number variant enrichments in genes involved in extracellular matrix (COL5A2/COL3A1/SNTA1) and collagen fibril organizations (COL5A2/COL3A1). Finally, differential expression of extracellular proteins was linked to connective tissue disorder in patients with recurrent sCeAD using a quantitative proteomics approach.

Conclusion

Current literature supports the hypothesis that an underlying, subclinical connective tissue disorder, likely genetically determined, may predispose to arterial wall weakness and sCeAD. Further studies with larger sample sizes and robust methodology are needed to better define the role of connective tissue in sCeAD pathogenesis.

Spontaneous Cervical Artery Dissection in Vascular Ehlers-Danlos Syndrome: A Cohort Study

BACKGROUND AND PURPOSE

Vascular Ehlers-Danlos syndrome is a rare inherited connective tissue disorder because of pathogenic variants in the COL3A1 gene. Arterial complications can affect all anatomic areas and about 25% involve supra-aortic trunks (SATs) but no systematic assessment of cervical artery lesions has been made. The primary objective was to determine an accurate prevalence of spontaneous SAT lesions in a large series of patients with vascular Ehlers-Danlos syndrome at diagnosis and during follow-up. Secondary objectives were to study their neurological consequences (transient ischemic attack or stroke) and the possible relationships with sex, genotype, ascertainment status.

METHODS

A retrospective review of a monocentric cohort of patients with molecularly proven vascular Ehlers-Danlos syndrome followed in a tertiary referral center from 2000 to 2017.

RESULTS

One hundred forty-four patients were analyzed, 56.9% (n=82) had SAT lesions: 64.6% females, 74.4% index-case patients. Most lesions were identified in early arterial assessment (48% at first work-up, mean age of 35.7±13.0 years). Cumulative incidence of a first identification of a SAT lesion was 41.7% at 40 years old. On the complete period of survey, 183 SAT lesions (with 132 dissections and 33 aneurysms) were identified, mainly in internal carotid arteries (56.3%) and vertebral arteries (28.9%), more rarely in patients with COL3A1 null mutations (P=0.008). Transient ischemic attack or stroke were reported in n=16 (19.5%) of the 82 patients with SAT lesions without relation with age, sex, treatment, or hypertension.

CONCLUSIONS

Cervical artery lesions are frequent and mostly asymptomatic in patients with vascular Ehlers-Danlos syndrome. Local dissections and aneurysms are the most frequent type of lesions, but transient ischemic attack or stroke seem rare.

Non-Atherosclerotic Vascular Disease in Women

OPINION STATEMENT

Takayasu arteritis, fibromuscular dysplasia (FMD), spontaneous arterial dissection, Raynaud's phenomenon, and chilblains are vascular conditions that are associated with an increased predisposition in women and are often underdiagnosed. Takayasu arteritis has an incidence rate of 2.6 cases per million individuals per year in the USA and predominantly affects women of childbearing age. HLA-B5 genetic locus is linked with Takayasu arteritis susceptibility. Methods to determine active disease are limiting; currently utilized clinical and imaging findings and laboratory tests are of limited value for this purpose. Pregnancy poses risks for maternal and fetal complications, and these patients need additional monitoring and care before and after conception. Controlling hypertension and immunosuppression using steroids, biological and non-biological immunosuppressants, are key components of managing patients with this arteritis. FMD commonly affects middle-aged, white females. Its true prevalence is unknown. Renal and cerebrovascular beds are the most frequently involved vascular beds. Its clinical presentation varies from no symptoms to catastrophic events. Controlling vascular risk factors, periodic surveillance, and revascularization when indicated are important factors in FMD management. Spontaneous arterial dissections are less common, but are an important cause of morbidity and mortality in specific populations. Cervicocephalic dissection causes 10-20% of the strokes in young adults, and coronary artery dissection is the culprit in almost one fourth of young women presenting with acute myocardial infarction. Early diagnosis is key to improving prognosis in these patients, as the majority of patients have spontaneous resolution of the dissection with conservative management alone. Increased clinician awareness of the presentation features and angiographic findings are imperative for early diagnosis. Raynaud's phenomenon and chilblains are cold- or stress-induced cutaneous lesions, commonly involving distal extremities. Secondary causes such as connective tissue diseases and malignancies must be thoroughly excluded during evaluation of these conditions. Cold avoidance, systemic and local warming, and oral vasodilator therapy are the mainstays of therapy.

Vocal Cord Paralysis as the First Sign of Spontaneous Carotid Dissection in a Patient With Extracranial Internal Carotid Artery Aneurysm

INTRODUCTION

Spontaneous dissection of supra-aortic arteries is an exceptionally rare cause of vocal cord dysfunction. We are reporting a case of spontaneous carotid dissection and internal carotid artery aneurysm presenting as vocal cord paralysis.

CASE REPORT

A 44-year-old female was admitted with hoarseness and swallowing disorders. Diagnostic imaging revealed dissection and obliteration of the right internal carotid artery (ICA) 23 mm from the carotid bifurcation. Electromyography revealed unilateral paralysis/paresis of the right vocal cord. Genetic analyses for thrombophilia, methylenetetrahydrofolate reductase, and plasminogen activator inhibitor 1 were found to be at high risk. The patient was discharged after 5 days without any neurological findings, and control angiography revealed complete restitution of the flow in the right ICA one month later. However, a fusiform aneurysm of the distal part of the extracranial right ICA was detected and excluded with endovascular procedure.

CONCLUSION

Connective tissue systemic disorders and even mild trauma could initiate the dissection process of neck arteries. Precise diagnosis might be difficult even for an experienced neurologist, however, the final outcome is favorable.

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.

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.

The Association Between Cervical Spine Manipulation and Carotid Artery Dissection: A Systematic Review of the Literature

OBJECTIVE

Controversy surrounds the safety of cervical spine manipulation. Ischemic stroke secondary to cervical spine manipulation is a hypothesized adverse event. In Canada, the seriousness of these events and their perceived association to cervical spine manipulation has led some members of the public to call for a ban of the procedure. The primary objective of this study was to determine the incidence of internal carotid artery (ICA) dissection after cervical spine manipulation in patients who experience neck pain and its associated disorders. The secondary objective was to determine whether cervical spine manipulation is associated with an increased risk of ICA dissection in patients with neck pain, upper back pain, or headaches.

METHODS

We systematically searched MEDLINE, CINAHL, Alternative Health, AMED, Index to Chiropractic Literature, and EMBASE from 1970 to November 2012. Two independent reviewers used standardized criteria to screen the eligibility of articles. We considered cohort studies, case-control studies, and randomized clinical trials that addressed our objectives. We planned to critically appraise eligible articles using the Scottish Intercollegiate Guideline Network methodology.

RESULTS

We did not find any epidemiologic studies that measured the incidence of cervical spine manipulation and ICA dissection. Similarly, we did not find any studies that determined whether cervical spine manipulation is associated with ICA dissection.

CONCLUSIONS

The incidence of ICA dissection after cervical spine manipulation is unknown. The relative risk of ICA dissection after cervical spine manipulation compared with other health care interventions for neck pain, back pain, or headache is also unknown. Although several case reports and case series raise the hypothesis of an association, we found no epidemiologic studies that validate this hypothesis.

Cervical artery dissection: emerging risk factors

Cervical artery dissection (CAD) represents an increasingly recognized cause of stroke and the most common cause of ischemic stroke in young adults. Many factors have been identified in association with CAD such as primary disease of arterial wall (fibrodysplasia) and other non-specific diseases related to CAD like Ehlers Danlos-syndrome IV, Marfan's syndrome, vessel tortuosity. Moreover, an underlying arteriopathy which could be in part genetically determined, has been suspected. The rule of emerging risk factors for CAD such as recent respiratory tract infection, migraine and hyperhomocysteinemia are still a matter of research. Other known risks factors for CAD are major head/neck trauma like chiropractic maneuver, coughing or hyperextension injury associated to car. We examined emerging risks factors for CAD detected in the last years, as CAD pathogenesis is still not completely understood and needs further investigations.

The genetics of cervical artery dissection: a systematic review

BACKGROUND AND PURPOSE

The pathophysiology of cervical artery dissections (CAD), a major cause of ischemic stroke in young adults, is poorly understood. Several arguments suggest a genetic predisposition.

METHODS

We systematically reviewed all published data on genetic risk factors for CAD and performed a meta-analysis of association studies with the MTHFR C677T polymorphism.

RESULTS

Rarely, CAD is associated with a known monogenic connective tissue disease, mainly vascular Ehlers-Danlos syndrome. However, in the large majority of CAD cases, there is no evidence for a known monogenic disease. Several arguments, including the association of CAD with dermal connective tissue abnormalities that are inherited, suggest that genetic factors also play a role in "sporadic" CAD as part of a multifactorial predisposition. We identified 15 genetic association studies: 10 were negative and 5 reported associations of 3 genetic variants in 3 different candidate genes. Two studies reported associations with polymorphisms in ICAM-1 and COL3A1, but neither has been replicated. Three studies reported an association with the MTHFR 677TT genotype, but 3 other studies did not replicate this. A meta-analysis of these data identified an overall significant association of the MTHFR 677TT genotype with CAD (OR, 1.67; 95% CI, 1.21 to 2.31). We also identified 9 studies screening candidate genes for mutations and 4 linkage studies, yielding mostly negative results.

CONCLUSIONS

Although several interesting hypotheses were generated, the majority of genetic studies in CAD have been negative until now, but they were markedly underpowered. Progress in unraveling the genetics of CAD will require the collection of DNA samples from large multicenter series.

Traumatic carotid cavernous fistula with bilateral carotid artery and vertebral artery dissections

Carotid and vertebral artery dissections from blunt cervical trauma are uncommon injuries that in recent years are becoming increasingly recognized as a result of angiographic screening protocols in trauma patients. Traumatic carotid cavernous fistulas are even less common events, but represent the most common intracranial vascular anomaly after head injury. The present report details the unique case of a woman with no history of collagen vascular disease who developed dissections of both carotid and both vertebral arteries, as well as a direct carotid cavernous fistula, after a motor vehicle collision. Her vascular injuries resolved without need for surgical or endovascular intervention.

Non-Atherosclerotic Vascular Disease in the Young

There are a large variety of non-atherosclerotic causes of ischemic stroke in the young. Arterial dissection, most commonly associated with non-traumatic causes, is among the most common. Both the carotid and vertebrobasilar circulations can be affected. The vasculitidies represent a rare, but potentially treatable series of conditions that can lead to stroke through diverse mechanisms. Moyamoya is a nonatherosclerotic, noninflammatory, nonamyloid vasculopathy characterized by chronic progressive stenosis or occlusion of the distal internal carotid arteries and/or proximal portions of the middle and/or anterior cerebral arteries. Moyamoya can be idiopathic (moyamoya disease) or the result of other conditions. An appreciation of the unusual causes of stroke in the young is important when considering secondary prevention measures.

A systematic review of the risk factors for cervical artery dissection

BACKGROUND AND PURPOSE

Cervical artery dissection (CAD) is a recognized cause of ischemic stroke among young and middle-aged individuals. The pathogenesis of dissections is unknown, although numerous constitutional and environmental risk factors have been postulated. To better understand the quality and nature of the research on the pathogenesis of CAD, we performed a systematic review of its risk factors.

METHODS

PubMed [MEDLINE (1966 to February 22, 2005)] and Embase (1980 to February 22, 2005) were searched to identify studies fulfilling the inclusion criteria. Two reviewers independently assessed methodological quality of the primary studies. Relevant data were extracted, including the risk factor(s) investigated, characteristics of the study population, and strength of the association(s).

RESULTS

Thirty-one case-control studies were included for analysis. Selection bias, lack of control for confounding, and inadequate method of data analysis were the most common identified methodological shortcomings. Strong associations were reported from individual studies for the following risk factors: aortic root diameter >34 mm (odds ratio [OR=14.2; 95% confidence interval [CI], 3.2 to 63.6), migraine (ORadj, 3.6; 95% CI, 1.5 to 8.6), relative diameter change (>11.8%) during the cardiac cycle of the common carotid artery (ORadj, 10.0; 95% CI, 1.8 to 54.2), and trivial trauma (in the form of manipulative therapy of the neck) (ORadj, 3.8; 95% CI, 1.3 to 11). A weak association was found for homocysteine (2 studies: ORcrude, unknown; 95% CI, 1.05 to 1.52; ORcrude, 1.3; 95% CI, 1.0 to 1.7), and recent infection (ORadj, 1.60; 95% CI, 0.67 to 3.80). Two studies had conflicting findings for low levels of alpha1-antitrypsin, with the methodologically stronger study suggesting no association with CAD.

CONCLUSIONS

CAD is a multi-factorial disease. Many of the reviewed studies contained 2 or more major sources of bias commonly found in case-control studies. Only one study (of homocysteine) used healthy controls, a robust sample size, and had a low risk of biased results. The relationship between atherosclerosis and CAD has been insufficiently examined.

Defining the Effect of Cervical Manipulation on Vertebral Artery Integrity: Establishment of an Animal Model

BACKGROUND

Cervical spine manipulation is most often performed to affect relief of musculoskeletal complaints of the head and neck. Performed typically without complication, this modality is thought to be a potential cause of cerebrovascular injury, although a cause-effect relation has yet to be established. To explore this relation, an experimental platform is needed that is accessible and biologically responsive.

OBJECTIVE

To establish an animal model capable of accommodating (1) direct study of its vertebral arteries and (2) creation of controlled interventions simulating arterial injury.

STUDY DESIGN

Descriptive.

METHODS

Under fluoroscopic guidance, an ultrasonic catheter was inserted into the left vertebral artery of 3 anesthetized dogs. The ultrasonic probe was then drawn proximally through the artery at a specific rate, and cross-sectional images of the vessel were collected. These images were then reconstructed to provide a variety of 2- and 3-dimensional representations of the vessel. This procedure was repeated after the overinflation and/or displacement of an angiographic balloon within the vertebral artery itself.

RESULTS

The resulting ultrasonic images were able to delineate the structural layers that constitute the vertebral artery. Analysis of 2- and 3-dimensional reconstructions before and after angiographic intervention revealed the creation of discrete vascular injuries (aneurysm or dissection).

CONCLUSIONS

For the first time, an animal model has been established that permits direct interrogation of the internal structures of the vertebral artery. This model can also be manipulated to create "preexisting" vascular injuries that are thought to be possible prerequisites for cerebrovascular injury associated with manipulation. As a result, an experimental platform has been established that is capable of providing investigators of all backgrounds with the ability to quantify biologic and mechanical outcomes of cervical manipulation.

Pathogenesis of spontaneous cervico-cerebral artery dissection. A hypothesis and a review of the literature

The pathogenesis of spontaneous cervico-cerebral artery dissection remains speculative due to the rarity of histopathological observations, which often correspond to late stage lesions. Transposition of theoretic data from experimental models, study of pathologies with morphological lesions of the same type, and review of some clinical cases, suggest a sequence for the pathological events leading to arterial dissection. Arterial dysplasia, aneurysms and dissections could all result from vascular remodeling in response to endothelial injury. It induces morphologic changes of the internal elastic lamina, smooth muscle cell proliferation, various matrix abnormalities involving the fibrillary components or their enzymatic regulation, arterial wall neoangiogenesis and dissection. Endothelial dysfunction could so play a key role in the imbalance between arterial degenerative and reparative processes and the initiation of cervico-cerebral artery dissection.

Molecular pathogenesis of subarachnoid haemorrhage

Subarachnoid haemorrhage (SAH) results from leakage of blood into the subarachnoid space and carries high morbidity and mortality. However, there is limited understanding to date, of the risk factors, cellular, intermediate biochemical and genetic traits predisposing to SAH. Nevertheless, in conjunction with improved methods of diagnostic imaging and less invasive approaches to preventing aneurysmal rupture, there may be utility in gaining a better understanding of the pathogenesis and in identifying pre-disease markers. Additionally, it is not impossible that drugs of value (e.g. matrix or endothelial modifiers) could become available. Several different clinical subtypes can be recognised, distinguished by arterial or venous involvement, presence of unruptured arterial aneurysms, and apparently "sporadic" and "familial" occurrences. Epidemiological risk factors include alcohol consumption and smoking: hypertension is a risk factor for rupture. About 10% seem to reflect strong family history and this subset may be particularly illuminating with respect to the molecular pathogenesis. Haemodynamic stress and poor vascular structure may be the main mechanisms of pathogenesis. The epidemiological and statistical evidence for familial megaphenic genes and modifier genes is reviewed. This review focuses on the pathogenesis, as opposed to inflammatory response to SAH. It sets in context the roles of specific genes and their protein products, such as polycystin (PKD1), fibrillin (FBN1), collagen III (COL3A1), elastin (ELN), collagen IV, protease inhibitor or alpha1-antitrypsin (PI) and proteases. These considerations illustrate the shortfalls in current knowledge, the needs of future biochemical and cellular research and their potential implications for future prevention of this often fatal condition.

Simultaneous bilateral internal carotid and vertebral artery dissection following chiropractic manipulation: case report and review of the literature

Single-vessel cervical arterial dissections typically occur in young adults and are a common cause of cerebral ischemia and stroke. Although the pathogenesis of multivessel dissection is unclear, it is thought to be a consequence of underlying collagen vascular disease. We present a 34-year-old previously healthy man who developed bilateral internal carotid and vertebral artery dissection following chiropractic manipulation.

Exclusion mapping of the genetic predisposition for cervical artery dissections by linkage analysis

Skin biopsies from a patient with a dissection of the left internal carotid artery and from four of his children were analyzed by electron microscopy. The index patient and three children showed mild but regular electron microscopic connective tissue aberrations. They were considered as carriers of an unknown autosomal dominant mutation. Thirty-four candidate genes involved in the biosynthesis of the extracellular matrix were excluded by genetic linkage analysis as possible sites of a disease-causing mutation in this family (logarithm of odds [LOD]-score less than -2.0).

Causes and management of thunderclap headache: a comprehensive review

BACKGROUND

Thunderclap headache (or sudden severe headache) is an uncommon type of headache. Recognition and accurate diagnosis of this headache are important, because there is often a serious underlying brain disorder.

SUMMARY

In this article, causes and management of thunderclap headache are discussed. In the primary care setting, there is a serious cause in one third of patients, but in the hospital setting, up to two thirds of patients have a serious underlying brain disorder. Clues in history and physical examination can point to a possible serious underlying cause of thunderclap headache, such as subarachnoid hemorrhage, intracranial hematoma, or cerebral venous thrombosis. The remaining patients with thunderclap headache, however, have a primary headache disorder, such as migraine or (less frequently) tension headache with an unusual sudden onset, exertional headache, coital headache, cough headache, or cluster headache. The concept of thunderclap headache as a distinct clinical entity is discussed, with implications for its evaluation. Present radiological techniques are reviewed with regard to their diagnostic utility in detecting a serious brain disorder.

CONCLUSIONS

Thunderclap headache is an uncommon type of headache, and a serious underlying cause should be excluded.

Mutations in the tropoelastin gene (ELN) were not found in patients with spontaneous cervical artery dissections

BACKGROUND AND PURPOSE

The majority of patients with spontaneous cerebral artery dissection show ultrastructural alterations in dermal collagen and elastic fibers.

METHODS

We studied the gene encoding tropoelastin (ELN) by reverse transcription-polymerase chain reaction and subsequent sequence analysis in 10 patients with abnormalities in their elastic fibers.

RESULTS

No mutations were found in the whole coding region of the ELN gene. The simultaneous visualization and quantification of ELN splice variants by gene scanning enabled the analysis of the regulation of alternative splicing of ELN mRNA. No differences could be detected between fibroblast cultures of the patients and a control subject.

CONCLUSIONS

Neither mutations in the ELN gene nor dysregulation of its activity appears to be the cause of the connective tissue disorder that is found in most patients with spontaneous dissections.

Risk factors for arterial ischemic stroke in children

Since early recurrence occurs in at least 10% of patients presenting with their first stroke in childhood in the reported series, the search for modifiable risk factors should be a priority. Risk factors for stroke in adults include hypertension, diabetes, and smoking, as well as cardiac disease and sickle cell anemia; asymptomatic cerebrovascular disease and transient ischemic events may predict stroke in this age group. The investigation of a child with a stroke has traditionally focused on finding a single cause rather than looking for risk factors to which the patient may be exposed life long. Approximately half of children presenting with stroke have a known predisposing condition, but some have unexpected pathologies such as primary cerebrovascular disease associated with congenital heart anomalies, or may have modifiable risk factors such as hypertension associated with sickle cell disease. The literature on children presenting with initially unexplained (cryptogenic) stroke suggests that there is a daunting list of possible causes, but since the series have mainly been small, it has been difficult to evaluate the relative importance of the reported associations. This paper reviews the literature on congenital, genetic, and acquired risk factors for stroke in childhood, and includes data from the large series of patients seen at Great Ormond Street Hospital over the past 10 years. The majority have arteriographic abnormalities and there is little evidence for asymptomatic cardiac disease. Genetic predisposition, trauma, infection, and nutritional deficiencies appear to be important, although case-control studies will be required to prove causation. Appropriate screening for modifiable risk factors may lead to prevention of recurrence in some patients. In the long term, an understanding of the multiple etiologies of childhood cerebrovascular disease and ischemic stroke may lead to primary prevention in this age group, and perhaps in adults.

Stroke treatment-specific considerations

Unusual causes of stroke account for a minority of all strokes, but they have specific diagnostic and therapeutic implications which must be considered early in the clinical course. This article focuses on arteriopathies such as arterial dissection, vasospasm-induced stroke, and vasculitis; hematological disorders such as hypercoagulable states, disseminated intravascular coagulation, and sickle cell disease; migraine-induced stroke, and cerebral venous thrombosis.

Mutations in the COL5A1 coding sequence are not common in patients with spontaneous cervical artery dissections

BACKGROUND AND PURPOSE

The dermal connective tissue of most patients with spontaneous cervical artery dissections (sCAD) contains abnormal collagen fibers. This suggests a predisposing connective tissue defect. The ultrastructural abnormalities in the skin of patients with sCAD have similarity with the morphological alterations in patients with Ehlers-Danlos syndrome type II, a dominant hereditary disorder that has been correlated in some patients to mutations within the genes encoding type V collagen. The aim of this study was to assess the alpha 1 chain of type V collagen (COL5A1) as a candidate gene for sCAD.

METHODS

We searched for mutations in the COL5A1 gene in cDNA from cultured fibroblasts of 19 patients with sCAD using single-strand conformational polymorphism analysis and nucleotide sequence analysis of polymerase chain reaction-amplified fragments of the whole COL5A1 coding sequence.

RESULTS

We detected 1 missense mutation leading to a predicted amino acid (192D/N) substitution within the N-terminal propeptide in 2 siblings. All other patients showed regular COL5A1 sequences with some silent polymorphisms.

CONCLUSIONS

Mutations in the COL5A1 gene do not appear to be a major factor in the etiology of sCAD.

[Cervical artery dissection: recent data physiopathologic hypotheses]

INTRODUCTION

Cervicocranial arterial dissection is a major cause of cerebral infarction in young subjects. Traumatic and infectious factors are frequently suspected to be at the origin of cervicocranial artery dissection. However, they are usually too minor or too common to explain the vessel wall split-off. Underlying arteriopathy predisposing to dissections is therefore often suspected.

CURRENT KNOWLEDGE AND KEY POINTS

The hypothesis of an underlying arteriopathy is based in certain cases on either the discovery of hereditary connective tissue disorders (or secondary signs of these diseases) or their frequent association with vascular and cardiac morphological abnormalities, thus suggesting extracellular matrix abnormalities. Current histological and biochemical data do not suggest the existence of a unique form of the disease but rather indicate the presence of various matrix abnormalities that could involve one of the fibrillar components or its enzymatic regulation.

FUTURE PROSPECTS AND PROJECTS

Classification of dissections according to the various vascular wall alterations would therefore permit to better define recurrence and familial risks and to improve overall management of the patients.