Thrombophilia and first arterial ischaemic stroke: a systematic review

Pediatric Stroke: A Review of Common Etiologies and Management Strategies

Pediatric stroke is an important cause of mortality and morbidity in children. There is a paucity of clinical trials pertaining to pediatric stroke management, and solidified universal guidelines are not established for children the way they are for the adult population. Diagnosis of pediatric stroke can be challenging, and it is often delayed or mischaracterized, which can result in worse outcomes. Understanding risks and appropriate therapy is paramount to improving care.

The Genetic Landscape of Ischemic Stroke in Children - Current Knowledge and Future Perspectives

Stroke in childhood has multiple etiologies, which are mostly distinct from those in adults. Genetic discoveries over the last decade pointed to monogenic disorders as a rare but significant cause of ischemic stroke in children and young adults, including small vessel and arterial ischemic stroke. These discoveries contributed to the understanding that stroke in children may be a sign of an underlying genetic disease. The identification of these diseases requires a detailed medical and family history collection, a careful clinical evaluation for the detection of systemic symptoms and signs, and neuroimaging assessment. Establishing an accurate etiological diagnosis and understanding the genetic risk factors for stroke are essential steps to decipher the underlying mechanisms, optimize the design of tailored prevention strategies, and facilitate the identification of novel therapeutic targets in some cases. Despite the increasing recognition of monogenic causes of stroke, genetic disorders remain understudied and therefore under-recognized in children with stroke. Increased awareness among healthcare providers is essential to facilitate accurate diagnosis in a timely manner. In this review, we provide a summary of the main single-gene disorders which may present as ischemic stroke in childhood and describe their clinical manifestations. We provide a set of practical suggestions for the diagnostic work up of these uncommon causes of stroke, based upon the stroke subtype and imaging characteristics that may suggest a monogenic diagnosis of ischemic stroke in children. Current hurdles in the genetic analyses of children with ischemic stroke as well as future prospectives are discussed.

Hemostatic and Thrombotic Considerations in the Diagnosis and Management of Childhood Arterial Ischemic Stroke: A Narrative Review

Although rare in children, arterial ischemic stroke (AIS) is associated with increased mortality and neurological morbidity. The incidence of AIS after the neonatal period is approximately 1-2/100,000/year, with an estimated mortality of 3-7%. A significant proportion of children surviving AIS experience life-long neurological deficits including hemiparesis, epilepsy, and cognitive delays. The low incidence of childhood AIS coupled with atypical clinical-presentation and lack of awareness contribute to delay in diagnosis and consequently, the early initiation of treatment. While randomized-clinical trials have demonstrated the efficacy and safety of reperfusion therapies including thrombolysis and endovascular thrombectomy in appropriately-selected adult patients, similar data for children are unavailable. Consequently, clinical decisions surrounding reperfusion therapy in childhood AIS are either extrapolated from adult data or based on local experience. The etiology of childhood AIS is multifactorial, often occurring in the setting of both acquired and congenital risk-factors including thrombophilia. While multiple studies have investigated the association of thrombophilia with incident childhood AIS, its impact on stroke recurrence and therefore duration and intensity of antithrombotic therapy is less clear. Despite these limitations, a significant progress has been made over the last decade in the management of childhood AIS. This progress can be attributed to international consortiums, and in selected cohorts to federally-funded clinical trials. In this narrative review, the authors have systematically appraised the literature and summarize the hemostatic and thrombotic considerations in the diagnosis and management of childhood AIS focusing on the evidence supporting reperfusion therapies, relevance of thrombophilia testing, and duration and drug choices for secondary-prophylaxis.

Childhood stroke

Stroke is an important cause of neurological morbidity in children; most survivors have permanent neurological deficits that affect the remainder of their life. Stroke in childhood, the focus of this Primer, is distinguished from perinatal stroke, defined as stroke before 29 days of age, because of its unique pathogenesis reflecting the maternal-fetal unit. Although approximately 15% of strokes in adults are haemorrhagic, half of incident strokes in children are haemorrhagic and half are ischaemic. The causes of childhood stroke are distinct from those in adults. Urgent brain imaging is essential to confirm the stroke diagnosis and guide decisions about hyperacute therapies. Secondary stroke prevention strongly depends on the underlying aetiology. While the past decade has seen substantial advances in paediatric stroke research, the quality of evidence for interventions, such as the rapid reperfusion therapies that have revolutionized arterial ischaemic stroke care in adults, remains low. Substantial time delays in diagnosis and treatment continue to challenge best possible care. Effective primary stroke prevention strategies in children with sickle cell disease represent a major success, yet barriers to implementation persist. The multidisciplinary members of the International Pediatric Stroke Organization are coordinating global efforts to tackle these challenges and improve the outcomes in children with cerebrovascular disease.

The Genetic Basis of Strokes in Pediatric Populations and Insight into New Therapeutic Options

Strokes within pediatric populations are considered to be the 10th leading cause of death in the United States of America, with over half of such events occurring in children younger than one year of life. The multifactorial etiopathology that has an influence on stroke development and occurrence signify the importance of the timely recognition of both modifiable and non-modifiable factors for adequate diagnostic and treatment approaches. The early recognition of a stroke and stroke risk in children has the potential to advance the application of neuroprotective, thrombolytic, and antithrombotic interventions and rehabilitation strategies to the earliest possible timepoints after the onset of a stroke, improving the outcomes and quality of life for affected children and their families. The recent development of molecular genetic methods has greatly facilitated the analysis and diagnosis of single-gene disorders. In this review, the most significant single gene disorders associated with pediatric stroke are presented, along with specific therapeutic options whenever they exist. Besides monogenic disorders that may present with stroke as a first symptom, genetic polymorphisms may contribute to the risk of pediatric and perinatal stroke. The most frequently studied genetic risk factors are several common polymorphisms in genes associated with thrombophilia; these genes code for proteins that are part of the coagulation cascade, fibrolysis, homocystein metabolism, lipid metabolism, or platelets. Single polymorphism frequencies may not be sufficient to completely explain the stroke causality and an analysis of several genotype combinations is a more promising approach. The recent steps forward in our understanding of the disorders underlying strokes has given us a next generation of therapeutics and therapeutic targets by which to improve stroke survival, protect or rebuild neuronal connections in the brain, and enhance neural function. Advances in DNA sequencing and the development of new tools to correct human gene mutations have brought genetic analysis and gene therapy into the focus of investigations for new therapeutic options for stroke patients.

Pediatric Patient with Ischemic Stroke: Initial Approach and Early Management

Acute Ischemic Stroke (AIS) in children is an acute neurologic emergency associated with significant morbidity and mortality. Although the incidence of AIS in pediatric patients is considerably lower than in adults, the overall cumulative negative impact of the quality of life could be even higher in children. The age-related variable clinical presentation could result in a delay in diagnosis and could negatively influence the overall outcome. The early management should be based on early recognition, acute transfer to pediatric AIS centre, standardised approach (ABCDE), early neurologic examination together with neuroimaging (preferable Magnetic Resonance Imaging—MRI). The treatment is based on supportive therapy (normoxemia, normocapnia, normotension and normoglycemia) in combination with intravenous/intraarterial thrombolytic therapy and/or mechanical thrombectomy in selected cases. Pediatric stroke centres, together with the implementation of local stroke management protocols, could further improve the outcome of pediatric patients with AIS.

Hypoxic-ischemic injury causes functional and structural neurovascular degeneration in the juvenile mouse retina

Ischemic stroke is a major cause of long-term disabilities, including vision loss. Neuronal and blood vessel maturation can affect the susceptibility of and outcome after ischemic stroke. Although we recently reported that exposure of neonatal mice to hypoxia–ischemia (HI) severely compromises the integrity of the retinal neurovasculature, it is not known whether juvenile mice are similarly impacted. Here we examined the effect of HI injury in juvenile mice on retinal structure and function, in particular the susceptibility of retinal neurons and blood vessels to HI damage. Our studies demonstrated that the retina suffered from functional and structural injuries, including reduced b-wave, thinning of the inner retinal layers, macroglial remodeling, and deterioration of the vasculature. The degeneration of the retinal vasculature associated with HI resulted in a significant decrease in the numbers of pericytes and endothelial cells as well as an increase in capillary loss. Taken together, these findings suggest a need for juveniles suffering from ischemic stroke to be monitored for changes in retinal functional and structural integrity. Thus, there is an emergent need for developing therapeutic approaches to prevent and reverse retinal neurovascular dysfunction with exposure to ischemic stroke.

Prothrombotic Factors Have Significant Association with Arterial and Venous Strokes in Indian Tamilians

BACKGROUND

Prothrombotic factors have been correlated with vascular events in young patients, with recurrent strokes, and with venous thromboembolisms. However, their prevalence in adult strokes, in healthy populations, and in specific ethnic groups is not well defined. We investigated the association of prothrombotic factors with strokes in a South Indian Tamil population.

METHODS

In this hospital-based cross-sectional study, plasma homocysteine (Hcys), protein C and protein S activity levels, activated protein C resistance (APCR) as a surrogate for factor V Leiden (FVL), fibrinogen, and antithrombin III (ATIII) were determined from 75 consecutive patients with ischemic stroke (IS), 25 with cortical venous thrombosis (CVT), and 75 healthy control participants. The Student t test or Mann-Whitney U test was used for comparing prothrombotic factor levels between the stroke and control groups. The χ2 or Fisher exact test was used for comparisons of proportions of thrombophilia and estimation of odds ratios. Mid-P correction was done for multiple estimations.

RESULTS

Hcys levels in patients with IS were significantly higher compared with those in healthy control participants (P = 0.02). Proportions of ATIII deficiency and hyperfibrinogenemia were significantly higher in the IS group, and no healthy control participants had hyperfibrinogenemia. Protein C deficiency was more frequent in those with IS (17%; P < 8 × 10-5) and CVT (P < 10-7) compared with healthy control participants, and protein C activity levels (P = 0.016) were also significantly lower in patients with CVT. Other parameters had no significant associations with IS and CVT. The frequency of protein S deficiency was high in healthy control participants (60%) and in both patients with IS (45%; P = 0.1) and patients with CVT (48%; P = 0.4). No patients or control participants had abnormal APCR.

CONCLUSIONS

In Tamilian participants, several prothrombotic factors were associated with IS. Protein C deficiency alone was associated with CVT. Replication of the pattern in genetically linked populations around the world may affect management of stroke in those populations.

ADAMTS12, a new candidate gene for pediatric stroke

We recently reported a family-based genome wide association study (GWAS) for pediatric stroke pointing our attention to two significantly associated genes of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) gene family ADAMTS2 (rs469568, p = 8x10-6) and ADAMTS12 (rs1364044, p = 2.9x10-6). To further investigate these candidate genes, we applied a targeted resequencing approach on 48 discordant sib-pairs for pediatric stroke followed by genotyping of the detected non-synonymous variants in the full cohort of 270 offspring trios and subsequent fine mapping analysis. We identified eight non-synonymous SNPs in ADAMTS2 and six in ADAMTS12 potentially influencing the respective protein function. These variants were genotyped within a cohort of 270 affected offspring trios, association analysis revealed the ADAMTS12 variant rs77581578 to be significantly under-transmitted (p = 6.26x10-3) to pediatric stroke patients. The finding was validated in a pediatric venous thromboembolism (VTE) cohort of 189 affected trios. Subsequent haplotype analysis of ADAMTS12 detected a significantly associated haplotype comprising the originally identified GWAS variant. Several ADAMTS genes such as ADAMTS13 are involved in thromboembolic disease process. Here, we provide further evidence for ADAMTS12 to likely play a role in pediatric stroke. Further functional studies are warranted to assess the functional role of ADAMTS12 in the pathogenesis of stroke.

Recurrent stroke: the role of thrombophilia in a large international pediatric stroke population

Risk factors for arterial ischemic stroke in children include vasculopathy and prothrombotic risk factors but their relative importance to recurrent stroke is uncertain. Data on recurrent stroke from databases held in Canada (Toronto), Germany (Kiel-Lübeck/Münster), and the UK (London/Southampton) were pooled. Data were available from 894 patients aged 1 month to 18 years at first stroke (median age, 6 years) with a median follow-up of 35 months. Among these 894 patients, 160 (17.9%) had a recurrence between 1 day and 136 months after the first stroke (median, 3.1 months). Among 288 children with vasculopathy, recurrence was significantly more common [hazard ratio (HR) 2.5, 95% confidence interval (95% CI) 1.92-3.5] compared to the rate in children without vasculopathy. Adjusting for vasculopathy, isolated antithrombin deficiency (HR 3.9; 95% CI: 1.4-10.9), isolated elevated lipoprotein (a) (HR 2.3; 95% CI: 1.3-4.1), and the presence of more than one prothrombotic risk factor (HR 1.9; 95% CI: 1.12-3.2) were independently associated with an increased risk of recurrence. Recurrence rates calculated per 100 person-years were 10 (95% CI: 3-24) for antithrombin deficiency, 6 (95% CI: 4-9) for elevated lipoprotein (a), and 13 (95% CI: 7-20) for the presence of more than one prothrombotic risk factor. Identifying children at increased risk of a second stroke is important in order to intensify measures aimed at preventing such recurrences.

Do hospital doctors test for thrombophilia in patients with venous thromboembolism?

The predictive value of factor V Leiden and the G20210A prothrombin mutation regarding recurrent venous thromboembolism (VTE) is limited and does not influence subsequent patient management. Systematic testing for such genetic thrombophilia should be avoided, but to which extent such testing is practiced in a Swiss Hospital is unknown. To examine the current practice of factor V Leiden and/or G20210A prothrombin mutation testing in a University Hospital, and to assess the clinical consequences of testing on patients. 1388 adult patients (48.7% women) with a main diagnosis of VTE hospitalized at the Lausanne university hospital between January 2013 and December 2015. FV Leiden and/or prothrombin G20210A mutation testing was performed in 61 (4.4%) patients with VTE, an average of 20 patients/year. On multivariable analysis, age < 65 years [odds ratio and (95% confidence interval) 5.91 (3.12-11.19)], being admitted in a medical ward [5.71 (2.02-16.16)] and staying in the intensive care unit [0.34 (0.12-0.97)] were associated with thrombophilia testing. No differences were found between patients with and without testing regarding in-hospital mortality [OR and 95% CI for tested vs. non-tested: 0.23 (0.03-1.73), p = 0.153] and length of stay (multivariable adjusted average ± standard error: 16.9 ± 3.3 vs. 20.0 ± 0.7 days for tested and non-tested patients, respectively, p = 0.875). Thrombophilia testing in hospitalized patients with a main diagnosis of VTE is seldom performed. FV Leiden and/or prothrombin G20210A mutation should not be routinely assessed in patients with acute VTE.

Recent developments and new frontiers in childhood arterial ischemic stroke

This review will discuss important developments in childhood arterial ischemic stroke over the past decade, focusing on improved understanding of the causes, consequences, and targets for intervention. Risk factors for childhood arterial ischemic stroke are different to adults. Infections, particularly herpes group viruses, are important precipitants for stroke. Non-atherosclerotic arteriopathies are the most common cause of childhood arterial ischemic stroke and an important predictor of recurrent events. Recent advances include the identification of serum biomarkers for inflammation and endothelial injury, and imaging biomarkers to monitor for vascular progression. Multicenter trials of immunotherapies in focal cerebral arteriopathies are currently in development. Recognition of clinical and radiological phenotypic patterns has facilitated the discovery of multisystem disorders associated with arterial ischemic stroke including ACTA2 arteriopathy and adenosine deaminase 2 deficiency. Identification of these Mendelian disorders provide insights into genetic mechanisms of disease and have implications for medical and surgical management. In contrast to adults, there are long diagnostic delays in childhood arterial ischemic stroke. Refinement of pediatric Code Stroke protocols and clinical decision support tools are essential to improve diagnostic certainty and improve access to reperfusion therapies. Children do not recover better than adults following arterial ischemic stroke, with more than half of survivors having long-term impairments. The physical, cognitive, and behavioral consequences of childhood arterial ischemic stroke are increasingly reported but further research is required to understand their impact on participation, quality of life, psychosocial, and family functioning. Longitudinal studies and the use of advanced imaging techniques, to understand neurobiological correlates of functional reorganization, are essential to developing targeted intervention strategies to facilitate recovery.

Advances in predicting venous thromboembolism risk in children

Paediatric venous thromboembolism (VTE) is a rare disorder but a rising incidence has been observed in recent years, due to improved VTE diagnosis and increased use of central venous catheters in the treatment of severe diseases. Risk assessment strategies are well established for adult patients, however, similar guidelines for paediatric patients are largely lacking. Several risk prediction tools have been reported in recent literature, which make use of established risk factors to assess VTE risk in paediatric subgroups, such as hospitalised children, cancer-diagnosed children and paediatric trauma patients. Although these models suffer several limitations regarding their study size and heterogeneous selection of predictor variables, they offer potential for improving the thromboprophylaxis management in these children. Here, we give an overview on recently reported risk prediction models for paediatric VTE.

Arterial Ischemic Stroke in Children and Young Adults

PURPOSE OF REVIEW

This article reviews risk factors, recurrence risk, evaluation, management, and outcomes of arterial ischemic stroke in children and young adults.

RECENT FINDINGS

The risk for recurrence and mortality appear to be low for neonatal and childhood stroke. Most children have relatively mild deficits, but those who have greater neurologic deficits, poststroke epilepsy, or strokes early in life are at risk for lower overall cognitive function. Stroke recurrence and long-term mortality after stroke in young adults are greater than originally thought. Cognitive impairments, depression, and anxiety are associated with higher levels of poststroke unemployment and represent targets for improved poststroke care. Poststroke care in young adults involves more than medical management. Self-reported memory and executive function impairments may be more severe than what is detected by objective measures. Assessment of possible cognitive impairments and appropriate management of psychological comorbidities are key to maximizing the long-term functional outcome of stroke survivors.

SUMMARY

Childhood and young adult stroke survivors survive for many more years than older patients with stroke. To ensure that these survivors maximize the productivity of their lives, neurologists must not only optimize medical management but also recognize that impairments in cognition and mood may be remediable barriers to long-term functional independence.

Association Between the 20210G>A Prothrombin Gene Polymorphism and Arterial Ischemic Stroke in Children and Young Adults-Two Meta-analyses of 3586 Cases and 6440 Control Subjects in Total

BACKGROUND

Previous data have shown that the 20210G>A polymorphism of the Factor II gene is related to an increased prothrombin level, which may in turn lead to a procoagulant state. The heterogeneous and multifactorial character of arterial ischemic stroke often results in contradictory reports describing the association between the 20210G>A polymorphism and arterial ischemic stroke in different populations. We performed a meta-analysis of available data addressing the relation between the FII 20210G>A polymorphism and arterial ischemic stroke, both in young adults and children.

METHODS

We searched PubMed using appropriate keywords. The inclusion criteria for the study were as follows: case-control study, study population consisting of children, study population consisting of young adults, arterial ischemic stroke confirmed by magnetic resonance imaging or computed tomography, and English language. The exclusion criteria included lack of genotype or allele frequencies, study design other than a case-control study, outcome definition other than arterial ischemic stroke, and previously overlapped patient groups. Finally, 30 case-control studies (14 in children and 16 in young adults) were included. Statistical analyses were conducted using R software. Heterogeneity between the studies was evaluated using the Dersimonian and Laird's Q test. In the case of significant between-studies heterogeneity, the pooled odds ratio was estimated with a random-effects model, otherwise a fixed-effects model was used.

RESULTS

The pooled analysis showed that carriers of 20210A allele (GA+AA genotypes) of the prothrombin gene are more common in arterial ischemic stroke patients, both in children and young adults, than in control subjects (P = 0.006; odds ratio, 1.83; 95% confidence interval, 1.19 to 2.80 and P = 0.001; odds ratio, 1.69; 95% confidence interval, 1.25 to 2.28, respectively).

CONCLUSIONS

The results of the present meta-analysis have proven that the FII 20210G>A polymorphism is associated with arterial ischemic stroke in both pediatric and young adult patients.

Pediatric arterial ischemic stroke: Epidemiology, risk factors, and management

Pediatric arterial ischemic stroke (AIS) is an uncommon but important cause of neurologic morbidity in neonates and children, with consequences including hemiparesis, intellectual disabilities, and epilepsy. The causes of pediatric AIS are unique to those typically associated with stroke in adults. Familiarity with the risk factors for AIS in children will help with efficient diagnosis, which is unfortunately frequently delayed. Here we review the epidemiology and risk factors for AIS in neonates and children. We also outline consensus-based practices in the evaluation and management of pediatric AIS. Finally we discuss the outcomes observed in this population. While much has been learned in recent decades, many uncertainties sill persist in regard to pediatric AIS. The ongoing development of specialized centers and investigators dedicated to pediatric stroke will continue to answer such questions and improve our ability to effectively care for these patients.

Rare genetic variants in SMAP1, B3GAT2, and RIMS1 contribute to pediatric venous thromboembolism

Our study identified a region on chromosome 6 comprising the genes SMAP1, B3GAT2, and RIMS1 as novel susceptibility locus for pediatric VTE. Nonsynonymous variants in SMAP1 and RIMS1 are predicted as deleterious and may influence vesicle processing in blood cells.

Clinical presentation, etiology, and outcome of stroke in children: A hospital-based study

AIM

To describe clinical presentations, etiologies, and outcomes of stroke in Jordanian children.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of children diagnosed with ischemic stroke who presented to our clinic from January 2001 to June 2014. Patients with onset of stroke in the neonatal period were excluded.

RESULTS

Twenty-four children (12 boys and 12 girls, with a male to female ratio of 1:1) were included in this study. The follow-up period ranged from 1 month to 9 years. Age at onset of the first stroke ranged from 1 month to 13 years. The most common initial clinical presentation was hemiparesis (58.3%). A known etiology was identified in 58.3% of patients. The most common etiologies were metabolic disorders, such as mitochondrial encephalopathy lactic acidosis and stroke (MELAS) and homocystinuria (25%), cardiac disorders (17%), and coagulopathy, such as a homozygous mutation in the MTHFR gene and a factor V Leiden mutation (17%). Recurrence of both clinical and silent strokes occurred in 46% of patients, residual motor weakness occurred in 58.3%, and residual epilepsy occurred in 29.2%.

CONCLUSION

Metabolic disorders, cardiac disorders, and coagulopathy are the causes of strokes in Jordanian children. Our results emphasized the importance of inherited disorders in Jordan.

Systematic review: hereditary thrombophilia associated to pediatric strokes and cerebral palsy

OBJECTIVES

This review aimed to organize and consolidate the latest knowledge about mutations and genetic polymorphisms related to hereditary thrombophilia and their potential association with pediatric stroke and cerebral palsy (CP).

SOURCES

Scientific articles published from 1993 to 2013, written in Portuguese, English, French, and Spanish, were selected and reviewed. The publications were searched in electronic databases, and also in the collections of local libraries. The terms "hereditary thrombophilia", "polymorphisms", "mutation", "pediatric strokes", and "cerebral palsy" were used for the research.

SUMMARY OF THE FINDINGS

The search in databases and in the bibliographic references retrieved 75 articles for inclusion in this review. Studies that investigated hereditary thrombophilias and their associations to CP and arterial and venous pediatric stroke presented contradictory results. The meta-analysis and case-control studies that showed positive results for this association described only slightly increased relative risks and sometimes had questionable conclusions. The association of two or more hereditary thrombophilias, or the association between thrombophilia and other specific clinical risk factors, suggest a higher risk of CP and pediatric stroke than isolated hereditary thrombophilia.

CONCLUSIONS

Larger, multicenter studies should be developed in order to elucidate the role of mutations leading to hereditary thrombophilia and the development of CP and pediatric stroke. The complex and multifactorial etiology of CP and stroke makes this an arduous and difficult task; however, the benefits generated by these studies are immeasurable.

The role of biochemical risk factors in the etiology of AIS in children and adults

Stroke is an abrupt onset of both focal and global neurological deficits secondary to a vascular event lasting more than 24 h and with a vascular background as its only cause. It can be triggered by a rupture of a blood vessel, aneurysm (hemorrhagic stroke, HS), thrombosis or embolisms (ischemic stroke, IS). In developed countries, it is the third most common cause of death in the adult population. Stroke in children is a rare disorder with a reported frequency of about 3 cases per 100,000 children per year. The history of acute brain ischemia is burdened with neurological complications such as motor impairment, speech impairment and intellectual delay. Moreover, in children after AIS seizures and epilepsy are also quite common. Stroke is a heterogeneous disorder; its risk factors in adults are well known, however, in pediatrics, in more than 20% cases, the cause of stroke is impossible to determine. Due to the fact that stroke usually arises as a consequence of the cerebral thrombosis, many of the mechanisms responsible for its occurrence can be considered as risk factors. We have reviewed the recent case-control studies conducted on pediatric patients regarding biochemical risk factors such as elevated levels of homocysteine, fibrinogen, protein C, protein S, antithrombin III, lipoprotein(a), cholesterol and its fractions, and compared them with the results obtained from adult patients.

The Association of Coagulation Factor V (Leiden) and Factor II (Prothrombin) Mutations With Stroke

Background:

Epidemiological studies indicate that over the past forty years, the stroke incidence rates has increased. Factors V and II mutations are established genetic-variant risk factors for venous thrombosis; however, their contribution to stroke is a controversial issue.

Objectives:

This study aimed to investigate the potential association of FV and FII mutations with stroke in an Iranian population.

Patients and Methods:

The study population consisted of 153 patients of different stroke subtypes (except cryptogenic strokes), admitted to Ghaem Hospital, Mashhad, Iran. The control group included 153 age- and sex-matched subjects without a history of cerebrovascular or neurologic diseases. Mutations of FV and FII were determined by using a TaqMan SNP Genotyping technique. The chi-square and Exact Fisher tests were used to analyze the baseline characteristics. Results were as follows: The calculated P-value for sex and diabetes mellitus were 0.907 and 1.000, respectively. The case and control groups were also matched in low density lipoprotein (P = 0.816), high density lipoprotein (P = 0.323), triglyceride (P = 0.846), and total cholesterol (P = 0.079).

Results:

Analysis of the FV showed that none of the study subjects were AA homozygous for this mutation and only 6 heterozygous subjects were detected in the case and control groups. Regarding FII variants, none of the study subjects were AG heterozygous and only 1 AA homozygous was detected in the control group.

Conclusions:

The prevalence of both FV and FII variants are population based. Iran is an ethnically diverse country. Therefore, for a comprehensive analysis of a potential association of FV and/or FII mutations with stroke among Iranian population, epidemiological studies could be conducted among different ethnic groups.

The role of genetic risk factors in arterial ischemic stroke in pediatric and adult patients: a critical review

The incidence of arterial ischemic stroke (AIS) in childhood (about 2-13 per 100,000 children a year) is much lower than the incidence in the adult population. Still, adverse outcomes of acute brain ischemia in childhood include death (10% of AIS children), neurological sequel, epileptic seizures (over 50%) and recurrence (over 20%). The knowledge of childhood stroke etiopathogenesis is still insufficient and the diagnostic and therapeutic procedures--controversial. Risk factors for childhood stroke differ from those observed in adults due to differing exposure to external risk factors. The most frequently reported risk factors for pediatric ischemic stroke are cerebral arteriopathies and vascular malformations, cardiac diseases, infections, traumas and metabolic diseases. Because of its multifactorial etiology pediatric AIS probably has a multigenic inheritance pattern. The genetic susceptibility to AIS may be determined by specific polymorphic variants encoding markers of hemostasis regulation and they are some of the most important targets in searching for genetic determinants in pediatric AIS. The authors have reviewed the recent literature on risk factors of childhood ischemic stroke with the focus on genetic factors like polymorphisms of genes encoding coagulation factors II, V, VII and XIII, MTHFR, fibrinogen beta, and compared them with the results performed in adult patients.

Multiple presence of prothrombotic risk factors in Croatian children with arterial ischemic stroke and transient ischemic attack

Aim

To determine the frequency of inherited and acquired prothrombotic risk factors in children with arterial ischemic stroke (AIS) and transient ischemic attacks (TIA) in Croatia.

Methods

We investigated 14 prothrombotic risk factors using blood samples from 124 children with AIS or TIA and 42 healthy children. Prothrombotic risk factors were classified into five groups: natural coagulation inhibitors (antithrombin, protein C, protein S), blood coagulation factors (FV Leiden and FII 20210), homocysteine, lipid and lipoprotein profile (lipoprotein (a), triglycerides, total, high- and low-density lipoprotein), and antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, and antiphosphatidylserine antibodies).

Results

The most common prothrombotic risk factor was elevated lipoprotein (a), which was identified in about 31% of patients and in 24% of controls. Natural coagulation inhibitors were decreased in about 19% of patients, but not in controls. Pathological values of homocysteine, blood coagulation factor polymorphisms, and antiphospholipid antibodies were found in similar frequencies in all groups. Fourteen children with AIS and TIA (11.3%) and no children from the control group had three or more investigated risk factors.

Conclusion

The presence of multiple prothrombotic risk factors in children with cerebrovascular disorder suggests that a combination of risk factors rather than individual risk factors could contribute to cerebrovascular disorders in children.

Association between prothrombin gene polymorphisms and hereditary thrombophilia in Xinjiang Kazakhs population

To assess the association between polymorphisms of prothrombin gene and hereditary thrombophilia in Xinjiang Kazakhs population. Through cross-sectional investigation, permanent Kazakh population of Ili Kazakh Autonomous Prefecture was selected as the study object to measure their antithrombin III (AT-III), protein C, protein S activity and activated C protein resistance value, thus defining the situation of the crowd's hereditary thrombophilia. Sequenom Massarray detection technology was used to conduct a genotype test of the six sites selected by the case and control groups. Haploview software was used to perform linkage disequilibrium analysis of the six sites, and the impact of the interaction between genetic variations and environment on hereditary thrombophilia was researched by the use of sum model. A total of 1005 Kazakh volunteers participated in the test (332 men and 673 women), average age (41.13 ± 11.50) years; the prevalence of hereditary thrombophilia in Xinjiang Kazakh population was 31.0%, and the prevalence of AT-III deficiency, protein C deficiency, protein S deficiency and activated protein C resistance was 16.4, 14.9, 20.6 and 7.8%, respectively. The difference in allele frequency of the hereditary thrombophilia patient group at rs3136447 and rs5896 sites was statistically significant (P = 0.0483 and P = 0.0302, respectively). rs5896 and rs2070852 had high linkage disequilibrium (r = 0.99), and constituted a single-domain block 1. The rs3136447 and the rs5896 polymorphisms located in the region of the prothrombin gene may be associated with hereditary thrombophilia in the Xinjiang Kazakhs population. There is additive interactive effect of rs5896 polymorphism (CT + TT) and smoke on hereditary thrombophilia.

Arteriopathy, D-dimer, and risk of poor neurologic outcome in childhood-onset arterial ischemic stroke

OBJECTIVE

To assess whether acute findings of cerebral arteriopathy, large infarct, and acutely elevated plasma D-dimer levels are independently prognostic of poor long-term neurologic outcome as measured at ≥ 1 year post-event in children with arterial ischemic stroke (AIS).

STUDY DESIGN

Sixty-one patients with childhood-onset (ie, >28 days of life) AIS were enrolled in a single-institution cohort study at Children's Hospital Colorado between February 2006 and June 2011. Data on demographic and diagnostic characteristics, antithrombotic treatments, and outcomes were systematically collected.

RESULTS

Cerebral arteriopathy and D-dimer levels >500 ng/mL (a measure of coagulation activation) were identified acutely in 41% and 31% of the cohort, respectively. Anticoagulation was administered in the acute period post-event in 40% of the children, in the subacute period in 43%, and in the chronic period in 28%. When not receiving anticoagulation, patients were routinely treated with aspirin 2-5 mg/kg once daily for a minimum of 1 year. Death, major bleeding (including intracranial hemorrhage), and recurrent AIS were infrequent. The Pediatric Stroke Outcome Measure at 1 year demonstrated poor outcome in 54% of the children. Acute cerebral arteriopathy and elevated D-dimer level were identified as putative prognostic factors for poor outcome; after adjustment for D-dimer, arteriopathy was an independent prognostic indicator (OR, 19.0; 95% CI, 1.6-229.8; P = .02).

CONCLUSION

Arteriopathy and coagulation activation are highly prevalent in the acute period of childhood AIS. Although recurrent AIS and intracranial hemorrhage were infrequent in our cohort, one-half of children experienced a poor neurologic outcome at 1 year, the risk of which was increased by acute arteriopathy. Substantiation of these findings in multi-institutional cohort studies is warranted, toward risk stratification in childhood-onset AIS.

Clinical profile, common thrombophilia markers and risk factors in 85 young Indian patients with arterial thrombosis

CONTEXT AND OBJECTIVE

Arterial thrombosis may occur consequent to hereditary thrombophilia and increased lipoprotein(a) [Lp(a)] and fibrinogen. Our aim was to study the prevalence of common thrombophilia markers in 85 consecutive cases of arterial thrombosis.

DESIGN AND SETTING

A retrospective study was conducted from 85 consecutive young patients treated as outpatients or admitted due to stroke or myocardial infarction at a tertiary care hospital.

METHODS

Eighty-five Indian patients (age < 45 years) presenting ischemic stroke (n = 48) or myocardial infarction (n = 37) and 50 controls were studied for seven thrombophilia markers including antithrombin (AT), factor V, protein C, protein S, activated protein C resistance (APC-R), fibrinogen and Lp(a). Functional assays for protein C, protein S, factor V and APC-R were performed using clotting-based methods. Semi-quantitative estimation of fibrinogen was done using Clauss's method and Lp(a) using immunoturbidimetry. Statistical analysis was done using the Epi Info 6 software.

RESULTS

Thirty-three samples (38.8%) tested positive for one or more thrombophilia markers. The three commonest abnormalities were elevated Lp(a) (20%), fibrinogen (17.6%) and low APC-R (14.2%). Low levels of protein C, protein S and AT were present in 4.7, 9.4 and 7% of the patients, respectively. Overall, the risk factor profile was: smoking (33%), positive family history (15.3%), hyperlipidemia (7%), hypertension, diabetes mellitus and obesity (2.3% each).

CONCLUSIONS

An association was found between low levels of protein C, protein S and AT and arterial thrombosis, but only elevated fibrinogen levels, smoking, positive family history and hyperlipidemia showed statistical significance.

A genome-wide association study identifies a gene network of ADAMTS genes in the predisposition to pediatric stroke

Pediatric stroke is a rare but highly penetrant disease with a strong genetic background. Although there are an increasing number of genome-wide association studies (GWASs) for stroke in adults, such studies for stroke of pediatric onset are lacking. Here we report the results of the first GWAS on pediatric stroke using a large cohort of 270 family-based trios. GWAS was performed using the Illumina 370 CNV single nucleotide polymorphisms array and analyzed using the transmission disequilibrium test as implemented in PLINK. An enrichment analysis was performed to identify additional true association signals among lower P value signals and searched for cumulatively associated genes within protein interaction data using dmGWAS. We observed clustering of association signals in 4 genes belonging to one family of metalloproteinases at high (ADAMTS12, P = 2.9 × 10−6; ADAMTS2, P = 8.0 × 10−6) and moderate (ADAMTS13, P = 9.3 × 10−4; ADAMTS17, P = 8.5 × 10−4) significance levels. Over-representation and gene-network analyses highlight the importance of the extracellular matrix in conjunction with members of the phosphoinositide and calcium signaling pathways in the susceptibility for pediatric stroke. Associated extracellular matrix components, such as ADAMTS proteins, in combination with misbalanced coagulation signals as unveiled by gene network analysis suggest a major role of postnatal vascular injury with subsequent thrombus formation as the leading cause of pediatric stroke.

Role of reduced ADAMTS13 in arterial ischemic stroke: a pediatric cohort study

OBJECTIVE

Previous studies in adults and mice have implicated ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), also known as von Willebrand factor (VWF)-cleaving protease, as a protective factor for stroke. Here we investigated ADAMTS13 in 208 pediatric patients with arterial ischemic stroke (AIS) and 125 population-based control children in a frequency-matched case-control study.

METHODS

The proportion of patients/controls with ADAMTS13 activity levels below and above the 10th percentile was compared. Additionally, in a quintile comparison, the proportion of patients versus controls in the lowest ADAMTS13 quintile was compared to those in the 2nd to 5th quintiles. Adjustment was performed for VWF antigen (VWF:Ag), factor VIII activity (FVIII:C), blood group, and age.

RESULTS

Forty-six of 208 patients (22%) showed ADAMTS13 levels below the 10th percentile, compared with 5 of 125 controls (4%; p < 0.001). Odds ratios/95% confidence intervals were 7.30/2.73-19.50 for the lowest percentile and 2.44/1.15-5.16 in the quintile comparison after adjustment for VWF:Ag, FVIII:C, blood group, and age. Comparing the proportion of patients with ADAMTS13 activity below the 10th percentile within the different stroke subtypes (undetermined, cardioembolic, steno-occlusive arteriopathies), no statistically significant differences were found (undetermined, 16 of 89; cardioembolic, 6 of 40; steno-occlusive arteriopathies, 24 of 79; p = 0.08). ADAMTS13 levels did not significantly differ among stroke subtypes (p = 0.29).

INTERPRETATION

Our findings implicate reduced ADAMTS13 activity as a risk factor for pediatric AIS, and support the concept that ADAMTS13 has a role in the pathogenesis of pediatric AIS.

Inherited prothrombotic risk factors in children with first ischemic stroke

Stroke in children is a heterogeneous disorder. Over 100 risk factors for stroke have been reported and genetic predisposition to stroke has been established. The most frequently reported risk factors are congenital heart malformations, hemolytic anemias, collagen vascular diseases, some rare inborn metabolic disorders, trauma, infection and thrombophilia. The aim of this article is to provide an overview of investigated inherited prothrombotic risk factors in children with first ischemic stroke. Various prothrombotic risk factors have been investigated in pediatric stroke including elevated homocysteine and lipoprotein (a), antithrombin, protein C and protein S deficiency, Factor V Leiden, Factor II G20210A and plasminogen activator inhibitor-1 4G/5G polymorphism. Despite similar criteria for inclusion of different studies in meta-analyses investigating first ischemic stroke in children, the obtained results were not consistent for all prothrombotic risk factors. The discrepancies found could be explained by methodological issues like different sample sizes, patient populations included and lack of controls. In order to provide the necessary power for randomized control trials, multi-center, multi-national approaches like International Pediatric Stroke Study have been initiated with the aim to describe risk factors for childhood stroke and explore their relationship with presentation, age, geography, and infarct characteristics. Although it is evident from numerous studies that the frequency of inherited prothrombotic factors is increased in pediatric stroke, single thrombophilia does not fully explain stroke in a child as it represents only a mild risk factor. Further studies are needed, as improved understanding of underlying mechanisms will improve primary and secondary prevention of childhood stroke.

Inherited thrombophilia in pediatric ischemic stroke: an Egyptian study

Pediatric stroke is relatively uncommon, with often subtle clinical presentations. Numerous predisposing risk factors can be both inherited and acquired, including cardiac disease, vascular abnormalities, infectious diseases, collagen tissue diseases, inborn errors of metabolism, anticardiolipin antibody, lupus anticoagulant, deficiencies of protein C, protein S, antithrombin, or plasminogen, and prothrombotic mutations. We explored risk factors, clinical features, and neuroimaging among Egyptian children with ischemic stroke, and estimated the prevalence of inherited thrombophilia. We included 20 children with ischemic stroke, recruited from the Pediatric Neurology Outpatient Clinic (Ain Shams University). Basic clinical evaluations for stroke and genotyping for factor V 1691 G-A (factor V Leiden), prothrombin 20210 G-A mutations, and methylenetetrahydrofolate reductase 677 C-T polymorphisms were performed using real-time polymerase chain reaction, with fluorescent melting curve detection analysis. Ten patients (50%) manifested methylenetetrahydrofolate reductase polymorphisms (six homozygotes and four heterozygotes). Heterozygous factor V Leiden was present in five (25%), whereas prothrombin mutation was present in only one (5%). Five patients (25%) manifested combined prothrombotic abnormalities. Thirteen demonstrated evidence of inherited thrombophilic disorder; 25% manifested more than one mutation. For appropriate risk assessment, even in the presence of overt acquired thrombotic risk factors, physicians should request complete thrombophilia screening for patients with stroke.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

Childhood arterial ischemic stroke: a review of etiologies, antithrombotic treatments, prognostic factors, and priorities for future research

Childhood arterial ischemic stroke (AIS) is a rare, but serious, medical condition, which is fatal in approximately 3% and associated with both acute and long-term neurologic impairment in over 70% of cases. Common etiologies include sickle cell disease, congenital heart disease, arterial dissection, prothrombotic conditions, and preceding viral infections; however, one in four cases is considered idiopathic. To date, no randomized controlled clinical trials (RCTs) have been conducted to establish evidence for current therapeutic strategies outside of sickle cell disease, thus, treatment strategies are largely shaped by consensus-based guidelines, in which, beyond the acute period, aspirin is the mainstay of therapy and anticoagulation is reserved for select circumstances. In recent years, evidence on prognostic factors has accumulated, helping to inform the future design of prognostically stratified RCTs. In this narrative review, we discuss the current understanding of etiologies, consensus-based treatment recommendations, contemporary treatment data, and prognostic factors in childhood AIS. We also identify priorities for future research.

Thromboembolism in pediatric inflammatory bowel disease: systematic review

BACKGROUND

Several studies suggest an increased risk of venous and arterial thromboembolism (TE) in adults with inflammatory bowel disease (IBD) compared to the general population. We performed a systematic review of studies on incidence and characteristic of TE in children with IBD.

METHODS

We searched Medline, LILACS, EMBASE, POPLINE, CINHAL, and reference lists of identified articles, without language restrictions, in August 2010.

RESULTS

Population studies suggest that there is an increased risk of TE in children with IBD compared to controls. TE occurred in children with IBD in all age ranges, mostly (82.8%) during active disease, and more frequently in children with ulcerative colitis (odds ratio [OR] 3.7, 95% confidence interval [CI] 1.8-7.6). At least one specific risk factor for TE was recognized in 50% of cases; two risk factors were present in 24%. Out of 92 published cases of TE in children with IBD, 54.3% occurred in cerebral site, 26% in the limbs, 13% in the abdominal vessels, and the remaining in the retina and lungs. After a first episode of TE, an early recurrence was observed in 11.4% of children, a late recurrence in 10%. A number of different therapeutic schemes were used. Overall mortality was 5.7% and was mostly associated with cerebral TE.

CONCLUSIONS

Population studies are needed to clarify the risk of TE in children with IBD, the relative weight of other risk factors, the characteristics of the events, and to define guidelines of therapy and prophylaxis.

Inherited thrombophilia in childhood arterial stroke: data from Lebanon

Pediatric ischemic stroke still represents a burden, and more than half of the survivors will experience cognitive or motor disabilities. The objective of this study was to investigate the role of thrombophilia in a cohort of children with arterial ischemic stroke. The records of infants and children with clinically and radiologically confirmed stroke were reviewed. Patients with venous or perinatal stroke were not included. Thirty-three patients were diagnosed with arterial ischemic stroke. The male/female ratio was 1.75:1. The median age was 4 years. The most frequent clinical manifestations were hemiparesis (54.5%) and seizures (33.3%). Genetic thrombophilia testing was available on 24 patients. Nine of the 24 patients (37.5%) were heterozygous for factor V Leiden. None of the patients carried the factor II G20210A variant. Ten patients (41.7%) were heterozygous and 3 (12.5%) were homozygous for methylenetetrahydrofolate reductase (MTHFR) C677T variant. Fifteen patients (62.5%) had one or more genetic polymorphism. Factor V Leiden was significantly associated with arterial ischemic stroke (P < 0.001). Stroke recurred in 2 children with multiple risk factors and MTHFR C677T mutation. Factor V Leiden is one of the major genetic risk factors for pediatric arterial ischemic stroke in Lebanon. MTHFR C677T was prevalent among patients with recurrent stroke.

A review of hereditary and acquired coagulation disorders in the aetiology of ischaemic stroke

The diagnostic workup in patients with ischaemic stroke often includes testing for prothrombotic conditions. However, the clinical relevance of coagulation abnormalities in ischaemic stroke is uncertain. Therefore, we reviewed what is presently known about the association between inherited and acquired coagulation disorders and ischaemic stroke, with a special emphasis on the methodological aspects. Good-quality data in this field are scarce, and most studies fall short on epidemiological criteria for causal inference. While inherited coagulation disorders are recognised risk factors for venous thrombosis, there is no substantial evidence for an association with arterial ischaemic stroke. Possible exceptions are the prothrombin G20210A mutation in adults and protein C deficiency in children. There is proof of an association between the antiphospholipid syndrome and ischaemic stroke, but the clinical significance of isolated mildly elevated antiphospholipid antibody titres is unclear. Evidence also suggests significant associations of increased homocysteine and fibrinogen concentrations with ischaemic stroke, but whether these associations are causal is still debated. Data on other acquired coagulation abnormalities are insufficient to allow conclusions regarding causality. For most coagulation disorders, a causal relation with ischaemic stroke has not been definitely established. Hence, at present, there is no valid indication for testing all patients with ischaemic stroke for these conditions. Large prospective population-based studies allowing the evaluation of interactive and subgroup effects are required to appreciate the role of coagulation disorders in the pathophysiology of arterial ischaemic stroke and to guide the management of individual patients.

The roles of anatomic factors, thrombophilia, and antithrombotic therapies in childhood-onset arterial ischemic stroke

Childhood-onset arterial ischemic stroke (AIS) is a rare disorder with high risks of both recurrent stroke and life-long neurological morbidity. Anatomic risk factors for primary and/or recurrent AIS include a venous thrombotic source for paradoxical embolism via a patent foramen ovale, primary cardioembolism, extracranial dissection, and intracranial arteriopathies, among others. Genetic and acquired thrombophilias are common, some of which have been shown to have prognostic influence on risk of recurrent AIS. While knowledge of childhood AIS risk factors has grown considerably in recent years, an evidence-based understanding of optimal antithrombotic therapy strategies has not yet been attained. Consensus-based guidelines have been developed, but future research must emphasize identification of additional prognostic factors and the initiation of cooperative randomized controlled clinical trials.

Plasma glutathione peroxidase in pediatric stroke families

BACKGROUND/OBJECTIVES

Promoter polymorphisms in the plasma glutathione peroxidase gene (GPX3), which encodes a major antioxidant enzyme implicated in post-translational modification of fibrinogen, have been implicated as risk factors for arterial ischemic stroke (AIS) and cerebral sinovenous thrombosis (CSVT) in young adults. However, the contribution of these polymorphisms could not be confirmed by other studies.

PATIENTS/METHODS

The aim of the present study was to investigate the association of three haplotype-tagging single-nucleotide polymorphisms (htSNPs) in GPX3 in a large family-based study sample comprising 268 nuclear families with different pediatric AIS subtypes, i.e. arteriopathy stroke (AS) and thromboembolic stroke (TS). In addition, an independent study sample comprising 154 nuclear families of pediatric CSVT was investigated. Single-point and haplotype association was assessed with the transmission disequilibrium test implemented in haploview.

RESULTS

Single-point analysis revealed that the G allele of htSNP rs8177412 was significantly overtransmitted to affected AS children (T/U = 25 : 11, χ(2) = 5.54, P = 0.019), but not to affected TS children (T/U = 49 : 40, χ(2) = 0.91, P = 0.34). The corresponding GG haplotype (H2: frequency 0.18) was also significantly overtransmitted to AS children (T/U = 23 : 11, χ(2) = 4.28, P= 0.03), but not to TS children or in children with CSVT. These results remained significant following 10,000 bootstrap permutations. Our findings indicate that genetic variants of GPX3 are risk factors for AS, but not for thromboembolic AIS or CSVT, in children.

CONCLUSIONS

Our results further highlight the need to analyze the contribution of genetic variants to pediatric AS, TS or CSVT separately, as these subcategories probably result from different combinations of risk-conferring and protective genetic variations.

Screening for coagulation disorders in patients with ischemic stroke

The role of coagulation disorders in the pathogenesis of (recurrent) ischemic stroke is uncertain. Therefore, the clinical utility of screening patients with ischemic stroke for these conditions and the therapeutic implications of a detected coagulation disorder in a patient who experienced ischemic stroke are uncertain. We reviewed the currently available data on the relationship between various inherited and acquired coagulation abnormalities (factor V Leiden and prothrombin G20210A mutations, deficiencies of protein C, protein S and anti-thrombin, hyperhomocysteinemia, the antiphospholipid syndrome and increased levels of fibrinogen) and ischemic stroke. Based on the existing evidence we discuss the usefulness of screening stroke patients for prothrombotic conditions and current recommendations regarding the optimal management of ischemic stroke patients in whom a coagulation disorder is found.

Factor V Leiden and prothrombin 20210G>A [corrected] mutation and paediatric ischaemic stroke: a case-control study and two meta-analyses

AIM

To determine whether factor V Leiden (FVL) and prothrombin (PT) 20210G>A mutation are associated with paediatric ischaemic stroke.

METHODS

The study consisted of two parts. Case-control study included neuroradiologically confirmed paediatric ischaemic stroke patients from two tertiary children's hospitals in Estonia. For control group, DNA was obtained from 400 anonymous screening test cards of newborns born consecutively in all delivery departments of Estonia in January 2005. Meta-analyses was performed to assess the association between paediatric sinovenous thrombosis and FVL and PT 20210G>A.

RESULTS

A total of 75 children (45 boys, 30 girls) were included into the case-control study: 19 with childhood arterial ischaemic stroke, 49 with perinatal arterial ischaemic stroke and seven with cerebral venous thrombosis. Both FVL and PT 20210G>A occurred significantly more frequently among patients with sinovenous thrombosis compared with controls (OR = 12.9; 95% CI: 2.3-73.0 and OR = 11.9; 95% CI: 2.1-67.2, respectively). The difference was not significant between childhood/perinatal arterial ischaemic stroke and controls. Meta-analyses (including our study) revealed that both FVL and PT 20210G>A are associated with paediatric sinovenous thrombosis (OR = 3.1; 95% CI: 1.8-5.5 and OR = 3.1; 95% CI: 1.4-6.8, respectively).

CONCLUSION

FVL and PT 20210G>A are associated with paediatric sinovenous thrombosis.

No early signs of atherosclerotic alterations in carriers of inherited thrombophilia

BACKGROUND

Congenital thrombophilia is a risk factor for venous thromboembolism (VTE). Whether it is associated with increased risk of arterial disease is today a matter of debate. We aimed to look for early signs of atherosclerotic alterations in carriers of inherited thrombophilic alterations (ITA).

METHODS

Between January 2006 and September 2008 ultrasonography assessment of the carotid arteries with measurement of intima-media thickness (IMT), and determination of the ankle/brachial pressure index (ABI), was performed in: a) 161 carriers of ITA (deficiency of antithrombin, protein C or S, factor V Leiden or prothrombin G20210A mutations), 84 of whom with previous VTE, and b) 180 subjects without ITA, matched for age, sex and previous VTE. All subjects were <66 year old.

RESULTS

Carotid plaques were found in 8 subjects [3 (1.9%) with ITA]. Increased IMT values (>1mm) were detected in 6 subjects with and 1 without thrombophilia (p=0.055). The prevalence of IMT values>90(th) percentile was not different in subjects with/without thrombophilia (15.2% vs 11.6%, p=0.416). At multivariate analysis only age was significantly associated with increased odds ratios for IMT values>90(th) percentile. No subjects had abnormal (<0.9) ABI values.

CONCLUSIONS

The present study, the first to investigate the presence of atherosclerotic markers in relatively young subjects with inherited thrombophilia, did not find a particular prevalence of signs of early atherosclerotic markers in these subjects.

Ischemic stroke in a 7-month-old infant with antiphospholipid antibody and homozygous C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism

Prothrombotic risk factors in children with ischemic stroke have been increasingly recognized with recent developments in technology. Extensive evaluation including a detailed family history is required to identify various inherited or acquired prothrombotic conditions. We report a 7-month-old male who presented with right hemiparesis. Acute cerebral infarction in the area supplied by the left lenticulostriate artery was confirmed through magnetic resonance imaging. De novo synthesis of antiphospholipid antibodies and homozygous methylenetetrahydrofolate reductase (MTHFR) polymorphism were identified as presumed prothrombotic risk factors. His twin sister and mother were also positive for antiphospholipid antibodies. Multiple risk factors for ischemic stroke should be considered, particularly in the perinatal and infancy period. This case also underlines the rare familial occurrence of antiphospholipid antibodies and its relationship to ischemic stroke in infancy.