Ethical and methodological issues in pedigree stroke research

Post-identifiability in changing sociotechnological genomic data environments

Data practices in biomedical research often rely on standards that build on normative assumptions regarding privacy and involve 'ethics work.' In an increasingly datafied research environment, identifiability gains a new temporal and spatial dimension, especially in regard to genomic data. In this paper, we analyze how genomic identifiability is considered as a specific data issue in a recent controversial case: publication of the genome sequence of the HeLa cell line. Considering developments in the sociotechnological and data environment, such as big data, biomedical, recreational, and research uses of genomics, our analysis highlights what it means to be (re-)identifiable in the postgenomic era. By showing how the risk of genomic identifiability is not a specificity of the HeLa controversy, but rather a systematic data issue, we argue that a new conceptualization is needed. With the notion of post-identifiability as a sociotechnological situation, we show how past assumptions and ideas about future possibilities come together in the case of genomic identifiability. We conclude by discussing how kinship, temporality, and openness are subject to renewed negotiations along with the changing understandings and expectations of identifiability and status of genomic data.

Becoming and being a biobank donor: The role of relationships and ethics

Relational aspects, such as involvement of donor's relatives or friends in the decision-making on participation in a research biobank, providing relatives' health data to researchers, or sharing research findings with relatives should be considered when reflecting on ethical aspects of research biobanks. The aim of this paper is to explore what the role of donor's relatives and friends is in the process of becoming and being a biobank donor and which ethical issues arise in this context. We performed qualitative analysis of 40 qualitative semi-structured interviews with biobank donors and researchers. The results show that relatedness to relatives or other types of close relationships played a significant role in the donors' motivation to be involved in a biobank, risk-benefit assessment, and decisions on sharing information on research and its results. Interviewees mentioned ethical issues in the context of sharing relatives' health-related data for research purposes and returning research findings that may affect their relatives. We conclude that the question of what information on family members may be shared with a biobank by research participants without informed consent of those relatives, and when family members become research subjects, lacks a clear answer and detailed guidelines, especially in the context of the introduction of the European Union's (EU) General Data Protection Regulation. Researchers in Latvia and EU face ethical questions and dilemmas about returning research results and incidental findings to donors' relatives, and donors need more information on sharing research results with relatives in the informed consent process.

Bio-repository of DNA in stroke: a study protocol of three ancestral populations

Stroke is a leading cause of death and disability in the world. Identifying the genes underlying stroke risk may help us to improve our understanding of the mechanisms that cause stroke and also identify novel therapeutic targets. To have sufficient power to disentangle the genetic component of stroke, large-scale highly phenotyped DNA repositories are necessary. The BRAINS (Bio-repository of DNA in stroke) study aims to recruit subjects with all subtypes of stroke as well as controls from UK, India, Sri Lanka and Qatar. BRAINS-UK will include 1500 stroke patients of European ancestry as well as British South Asians. BRAINS-South Asia aims to recruit 3000 stroke subjects and 3000 controls from across India and Sri Lanka. BRAINS-Middle East aims to enrol 1500 stroke patients from Qatar. The controls for BRAINS-Middle East will be recruited from a population-based Qatari Biobank. With the addition of new recruitment centres in India and Qatar, we present an updated version of the BRAINS study protocol. This is the first international DNA biobank for stroke patients and controls from the Middle East. By investigating the influence of genetic factors on stroke risk in European, South Asian and Middle Eastern populations, BRAINS has the potential to improve our understanding of genetic differences between these groups and may lead to new population-specific therapeutic targets.

Siblings with ischemic stroke study: results of a genome-wide scan for stroke loci

BACKGROUND AND PURPOSE

Ischemic stroke has a strong familial component to risk. The Siblings With Ischemic Stroke Study (SWISS) is a genome-wide, family-based analysis that included use of imputed genotypes. The Siblings With Ischemic Stroke Study was conducted to examine the associations between single-nucleotide polymorphisms (SNPs) and risk of stroke and stroke subtypes within pairs.

METHODS

The Siblings With Ischemic Stroke Study enrolled 312 probands with ischemic stroke from 70 US and Canadian centers. Affected siblings were ascertained by centers and confirmed by central record review; unaffected siblings were ascertained by telephone contact. Ischemic stroke was subtyped according to Trial of Org 10172 in Acute Stroke Treatment criteria. Genotyping was performed with an Illumina 610 quad array (probands) and an Illumina linkage V array (affected siblings). SNPs were imputed by using 1000 Genomes Project data and MACH software. Family-based association analyses were conducted by using the sibling transmission-disequilibrium test.

RESULTS

For all pairs, the correlation of age at stroke within pairs of affected siblings was r=0.83 (95% CI, 0.78-0.86; P<2.2×10(-16)). The correlation did not differ substantially by subtype. The concordance of stroke subtypes among affected pairs was 33.8% (kappa=0.13; P=5.06×10(-4)) and did not differ by age at stroke in the proband. Although no SNP achieved genome-wide significance for risk of ischemic stroke, there was clustering of the most associated SNPs on chromosomes 3p (neuronal nitric oxide synthase) and 6p.

CONCLUSIONS

Stroke subtype and age at stroke in affected sibling pairs exhibit significant clustering. No individual SNP reached genome-wide significance. However, 2 promising candidate loci were identified, including 1 that contains neuronal nitric oxide synthase, although these risk loci warrant further examination in larger sample collections.

Genomic risk profiling of ischemic stroke: results of an international genome-wide association meta-analysis

INTRODUCTION

Familial aggregation of ischemic stroke derives from shared genetic and environmental factors. We present a meta-analysis of genome-wide association scans (GWAS) from 3 cohorts to identify the contribution of common variants to ischemic stroke risk.

METHODS

This study involved 1464 ischemic stroke cases and 1932 controls. Cases were genotyped using the Illumina 610 or 660 genotyping arrays; controls, with Illumina HumanHap 550Kv1 or 550Kv3 genotyping arrays. Imputation was performed with the 1000 Genomes European ancestry haplotypes (August 2010 release) as a reference. A total of 5,156,597 single-nucleotide polymorphisms (SNPs) were incorporated into the fixed effects meta-analysis. All SNPs associated with ischemic stroke (P<1×10(-5)) were incorporated into a multivariate risk profile model.

RESULTS

No SNP reached genome-wide significance for ischemic stroke (P<5×10(-8)). Secondary analysis identified a significant cumulative effect for age at onset of stroke (first versus fifth quintile of cumulative profiles based on SNPs associated with late onset, ß = 14.77 [10.85,18.68], P = 5.5×10(-12)), as well as a strong effect showing increased risk across samples with a high propensity for stroke among samples with enriched counts of suggestive risk alleles (P<5×10(-6)). Risk profile scores based only on genomic information offered little incremental prediction.

DISCUSSION

There is little evidence of a common genetic variant contributing to moderate risk of ischemic stroke. Quintiles based on genetic loading of alleles associated with a younger age at onset of ischemic stroke revealed a significant difference in age at onset between those in the upper and lower quintiles. Using common variants from GWAS and imputation, genomic profiling remains inferior to family history of stroke for defining risk. Inclusion of genomic (rare variant) information may be required to improve clinical risk profiling.

Bio-Repository of DNA in stroke (BRAINS): a study protocol

Background

Stroke is one of the commonest causes of mortality in the world and anticipated to be an increasing burden to the developing world. Stroke has a genetic basis and identifying those genes may not only help us define the mechanisms that cause stroke but also identify novel therapeutic targets. However, large scale highly phenotyped DNA repositories are required in order for this to be achieved.

Methods

The proposed Bio-Repository of DNA in Stroke (BRAINS) will recruit all subtypes of stroke as well as controls from two different continents, Europe and Asia. Subjects recruited from the UK will include stroke patients of European ancestry as well as British South Asians. Stroke subjects from South Asia will be recruited from India and Sri Lanka. South Asian cases will also have control subjects recruited.

Discussion

We describe a study protocol to establish a large and highly characterized stroke biobank in those of European and South Asian descent. With different ethnic populations being recruited, BRAINS has the ability to compare and contrast genetic risk factors between those of differing ancestral descent as well as those who migrate into different environments.

Joint Commission primary stroke center certification does not affect proband enrollment: the siblings with ischemic stroke study

BACKGROUND

The Joint Commission (JC) certifies primary stroke centers in the United States. Whether certification promotes enrollment of study subjects into stroke research studies is not known. We examined whether enrollment performance of centers was related to JC certification status.

METHODS

The 51 US Siblings with Ischemic Stroke Study (SWISS) centers were characterized by JC certification status, year of certification, year initiated into SWISS, center location, and whether the center had a vascular/stroke neurology fellowship program accredited by the Accreditation Council for Graduate Medical Education. Performance measures included days elapsed from initiation to first enrollment, total enrollments within 12 months after initiation, and annual rate of enrollment thereafter.

RESULTS

In all, 36 of 51 SWISS sites (71%) were JC certified. A total of 32 (63%) were initiated into the study from 2000 through 2002, and 19 (37%) were initiated from 2005 through May 2008. Comparison of certified and noncertified sites showed no significant difference in the time to first enrollment (median, 77.5 v 115 days; P = .90), total enrollees in the first year (median, 3 v 2 probands; P = .69), or annual enrollment rate (median, 1.9 v 1.8 probands; P = .72). The rate of enrollment or time to first enrollment was not different between 2000-to-2002 and 2005-to-2008 sites. Early-initiated centers tended to have better year-1 enrollment than later-initiated centers (3 v 2 probands; P = .056).

CONCLUSIONS

JC certification did not have a significant effect on SWISS center enrollment. The JC should encourage the research mission among certified stroke centers.

Personal privacy and public health: potential impacts of privacy legislation on health research in Canada

Despite variation in Canadian privacy laws between provinces and territories, increasing legislative protection of personal privacy has imposed restrictions on health research across the country. The effects of these restrictions on patient recruitment include increased study costs, durations, and decreased participation rates. Low participation rates can jeopardize the validity of research findings and the accuracy of measures of association by introducing non-response, or participation bias. We constructed simulations to assess potential effects of non-response bias on the accuracy of measures of association in a hypothetical case-control study. Small biases that alter the probability of selecting an exposed case can lead to dramatic inflation or attrition of the odds ratio (OR) in case-control studies. ORs are more unstable and subject to error when the true probability of selecting an exposed case is greater, such that strong positive associations are subject to error even at low levels of bias. Well-powered, population-based epidemiological research is a cornerstone of public health. Therefore, when weighing the benefits of protecting personal privacy, the benefits of valid and robust health research must also be considered. Options might include special legislative treatment of health research, or the use of an "opt-out" (vs. the current "opt-in") construct for consent in confidential research.

Impact of restricting enrollment in stroke genetics research to adults able to provide informed consent

BACKGROUND AND PURPOSE

The extent of potential consent bias in observational studies elucidating genetic and environmental contributions to ischemic stroke is largely unknown. The purpose of this study was to assess differences in stroke cohort characteristics between those who provided informed consent and those whose enrollment was authorized by surrogate decision makers.

METHODS

The Ischemic Stroke Genetics Study (ISGS) is a prospective, 5-center, case-control study of first-ever ischemic stroke. Demographic, clinical, and stroke characteristics were compared between cases enrolled by self versus by surrogate. Data from one site that limits enrollment only to those able to self-consent were also analyzed to compare those who enrolled with those not able to consent.

RESULTS

Overall, 10% (54 of 517) were enrolled using surrogate authorization. Self-consented and surrogate-authorized cases did not differ significantly in age, sex, or conventional risk factors. Surrogate-authorized cases had significantly more severe stroke deficits, larger infarcts, and infarcts localizing to left supratentorial regions. Similarly, at the site restricting enrollment, stroke severity and characteristics differed between self-consented individuals and those otherwise eligible but unable to provide consent.

CONCLUSIONS

Failure to permit surrogate authorization in genetic studies of ischemic stroke may skew enrollment toward less severe strokes caused by smaller infarcts. This potential consent bias may undermine the ability to identify genetic determinants of risk and severity and suggests that surrogate enrollment in these studies can be ethically justifiable.

Willingness of ischemic stroke patients to donate DNA for genetic research: a systematic review

Systematic differences between eligible subjects who participate in research and those who do not are a form of selection bias. The aim of this study was to determine whether published reports of genetic studies of stroke provide sufficient information on the willingness of subjects to participate to assess the potential for bias. We conducted a systematic 2-person review of the English-language literature based on a MEDLINE search for studies on the genetics of ischemic stroke published between January 2000 and January 2002. Of the 41 studies that met the search criteria, only 6 (15%) provided information on the number of stroke patients who were eligible for DNA collection but refused to donate a DNA sample: 4 hospital-based case-control studies or case series and 2 population-based case-control studies of 1 cohort. The acceptance rate for participation was higher in the hospital-based case-control studies (95-99%) than in the population-based studies (75.2%). Scant data are available regarding the willingness of patients with ischemic stroke to participate in genetic studies. Methodologic and cultural differences may explain the broad range of acceptance rates for participation.

The Fangshan/Family-based Ischemic Stroke Study In China (FISSIC) protocol

BACKGROUND

The exact etiology of ischemic stroke remains unclear, because multiple genetic predispositions and environmental risk factors may be involved, and their interactions dictate the complexity. Family-based studies provide unique features in design, while they are currently underrepresented for studies of ischemic stroke in developing countries. The Fangshan/Family-based Ischemic Stroke Study In China (FISSIC) program aims to conduct a genetic pedigree study of ischemic stroke in rural communities of China.

METHODS/DESIGN

The pedigrees of ischemic stroke with clear documentation are recruited by using the proband-initiated contact method, based on the stroke registry in hospital and communities. Blood samples and detailed information of pedigrees are collected through the health care network in the rural area, and prospective follow-up of the pedigrees cohort is scheduled. Complementary strategies of both family-based design and matched case-spousal control design are used, and comprehensive statistical methods will be implemented to ascertain potential complex genetic and environmental factors and their interactions as well.

DISCUSSION

This study is complementary to other genetic pedigree studies of ischemic stroke, such as the Siblings With Ischemic Stroke Study (SWISS), which are established in developed countries. We describe the protocol of this family-based genetic epidemiological study that may be used as a new practical guideline and research paradigm in developing countries and facilitate initiatives of stroke study for international collaborations.

The Siblings With Ischemic Stroke Study (SWISS): a progress report

There is increasing evidence that genetic factors are associated with ischemic stroke, including multiple recent reports of association with the gene PDE4D, encoding phosphodiesterase 4D, on chromosome 5q12. Genetic studies of stroke are important but can be logistically difficult to perform. This article reviews the design of the Siblings With Ischemic Stroke Study (SWISS) and discusses problems in performing a sibling-based pedigree study where proband-initiated consent is used to enroll pedigree members. Proband-initiated enrollment optimizes privacy protections for family members, but it is associated with a substantial pedigree non-completion rate such that 3 to 4 probands must be identified to obtain one completed sibling pedigree. This report updates the progress of enrollment in the SWISS protocol, discusses barriers to pedigree completion and describes innovative approaches used by the SWISS investigators to enhance enrollment.

The impact of privacy protections on recruitment in a multicenter stroke genetics study

The authors reviewed the recruitment of stroke-affected sibling pairs using a letter-based, proband-initiated contact strategy. The authors randomly sampled 99 proband enrollment forms (Phase 1) and randomly sampled 50 sibling reply cards (Phase 2). The sibling response rate was 30.6%, for a pedigree response rate of 58%. Of the siblings who replied, 96% authorized further contact. Median time from proband enrollment to pedigree DNA banking, which required 3+ probands, was 134 days.

Cascade testing in familial hypercholesterolaemia: how should family members be contacted?

Cascade testing or screening provides an important mechanism for identifying people at risk of a genetic condition. For some autosomal dominant conditions, such as familial hpercholesterolaemia (FH), identifying relatives allows for significant health-affecting interventions to be administered, which can extend a person's life expectancy significantly. However, cascade screening is not without ethical implications. In this paper, we examine one ethically contentious aspect of cascade screening programmes, namely the alternative methods by which relatives of a proband can be contacted. Should the proband be invited to contact his or her family members, or should the screening programme contact family members directly? We argue that direct contact is an ethically justifiable method of contact tracing in cascade screening for FH. Not only has this method already been utilised without adverse effects, an examination of the ethical arguments against it shows these are unsubstantiated. We describe several criteria that, if met, will allow an appropriate balance to be struck between maximising the efficiency of family tracing and respecting the interests of probands and their relatives.

A survey of the SWISS researchers on the impact of sibling privacy protections on pedigree recruitment

To understand the perceptions and attitudes about privacy safeguards in research and investigate the impact of letter-based proband-initiated contact on recruitment, we surveyed researchers in the Siblings With Ischemic Stroke Study (SWISS). All 49 actively recruiting sites provided at least 1 response, and 61% reported that potential probands were enthusiastic. Although 66% of researchers valued proband-initiated contact, only 23% said that probands viewed this strategy as important to protecting the privacy of siblings. A substantial minority of researchers (37%) said the strategy impeded enrollment, and 44% said it was overly burdensome to probands.

Ethical issues in identifying and recruiting participants for familial genetic research

Family-based research is essential to understanding the genetic and environmental etiology of human disease. The success of family-based research often depends on investigators' ability to identify, recruit, and achieve a high participation rate among eligible family members. However, recruitment of family members raises ethical concerns due to the tension between protecting participants' privacy and promoting research quality, and guidelines for these activities are not well established. The Cancer Genetics Network Bioethics Committee assembled a multidisciplinary group to explore the scientific and ethical issues that arise in the process of family-based recruitment. The group used a literature review as well as expert opinion to develop recommendations about appropriate approaches to identifying, contacting, and recruiting family members. We conclude that there is no single correct approach, but recommend a balanced approach that takes into account the nature of the particular study as well as its recruitment goals. Recruitment of family members should be viewed as part of the research protocol and should require appropriate informed consent of the already-enrolled participant. Investigators should inform prospective participants why they are being contacted, how information about them was obtained, and what will happen to that information if they decide not to participate. The recruitment process should also be sensitive to the fact that some individuals from families at increased genetic risk will have no prior knowledge of their risk status. These recommendations are put forward to promote further discussion about the advantages and disadvantages of various approaches to family-based recruitment. They suggest a framework for considering alternative recruitment strategies and their implications, as well as highlight areas in need of further empirical research.

New advances in identifying genetic anomalies in stroke-prone probands

The past several years have been marked by significant progress in identifying genetic anomalies in stroke-prone probands. These advances have occurred in both highly penetrant single-gene disorders and in common stroke, which is influenced by risk/susceptibility genes. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can be challenging to diagnose because of the wide range of notch 3 mutations that can cause disease, but a new immunohistochemical technique using a skin biopsy sample appears to be highly sensitive and specific. In a landmark Icelandic study, linkage was established between stroke and a locus on chromosome 5q12 designated STRK1. Association studies continue to identify polymorphisms that predispose to stroke and to markers for cerebrovascular atherosclerosis, such as intima-media thickness. Intense interest now surrounds genes involved in inflammation, including genes that encode for the interleukin-1 receptor antagonist and paraoxonase-1. In the foreseeable future, prevention, diagnosis, and treatment will incorporate genetic data to refine and individualize management of cerebrovascular disease.

Curricular approaches to research ethics training for psychiatric investigators

RATIONALE

Training in research ethics is crucial for psychiatric investigators. Addressing ethical dimensions of human subjects research requires knowledge about the rules and norms governing research; sensitivity to ethical implications of actions; and skills in ethics problem solving. Investigators in training who are physicians have the additional challenge of developing identities as investigators that sometimes conflict with their identities as physicians.

OBJECTIVES

To propose a curriculum for psychiatric research ethics training.

METHODS

Review of literature on ethics education and presentation of a curricular approach to research ethics training for psychiatric investigators.

RESULTS

Research ethics can be learned and should be taught. Involvement of active investigators in teaching research ethics is important. While core topics of psychiatric research ethics training have not yet been identified, there are available models from which to draw. Research ethics should be introduced early and integrated throughout the research training period. Lack of resources and institutional support can be obstacles to development of comprehensive research ethics curricula. Small-group, case-based discussion is best for teaching ethics problem-solving skills. Examples of teaching module ideas and a fully developed sample teaching module are presented.

CONCLUSIONS

There is opportunity for creative models for teaching psychiatric research ethics. Work is needed to identify core topics, target pedagogical strategies to trainees at different levels, and develop evaluation methods.

The Ischemic Stroke Genetics Study (ISGS) Protocol

BACKGROUND

The molecular basis for the genetic risk of ischemic stroke is likely to be multigenic and influenced by environmental factors. Several small case-control studies have suggested associations between ischemic stroke and polymorphisms of genes that code for coagulation cascade proteins and platelet receptors. Our aim is to investigate potential associations between hemostatic gene polymorphisms and ischemic stroke, with particular emphasis on detailed characterization of the phenotype.

METHODS/DESIGN

The Ischemic Stroke Genetic Study is a prospective, multicenter genetic association study in adults with recent first-ever ischemic stroke confirmed with computed tomography or magnetic resonance imaging. Patients are evaluated at academic medical centers in the United States and compared with sex- and age-matched controls. Stroke subtypes are determined by central blinded adjudication using standardized, validated mechanistic and syndromic classification systems. The panel of genes to be tested for polymorphisms includes beta-fibrinogen and platelet glycoprotein Ia, Iba, and IIb/IIIa. Immortalized cell lines are created to allow for time- and cost-efficient testing of additional candidate genes in the future.

DISCUSSION

The study is designed to minimize survival bias and to allow for exploring associations between specific polymorphisms and individual subtypes of ischemic stroke. The data set will also permit the study of genetic determinants of stroke outcome. Having cell lines will permit testing of future candidate risk factor genes.

Ethical aspects of research into the etiology of autism

Advances in understanding autism and other developmental neuropsychiatric disorders will come from an integration of various research strategies including phenomenologic, functional neuroimaging, and pharmacologic methods, as well as epidemiologic approaches aimed at identifying genetic and environmental risk factors. The highly heritable nature of autism makes it scientifically valuable to involve parents and siblings as research participants. However, many studies on autism pose ethical challenges because they do not offer the prospect of direct benefit to subjects. In this article, we present an in-depth ethical analysis of current nontherapeutic research strategies that are common in autism research. The ethical analysis applies a proposed ethical framework for evaluating clinical research focusing on seven ethical requirements: (1) social or scientific value, (2) scientific validity, (3) fair subject selection, (4) favorable risk-benefit ratio, (5) independent review, (6) informed consent, and (7) respect for potential and enrolled research participants.

New advances in identifying genetic anomalies in stroke-prone probands

The past several years have been marked by significant progress in identifying genetic anomalies in stroke-prone probands. These advances have occurred in both highly penetrant single-gene disorders and in common stroke, which is influenced by risk/susceptibility genes. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can be challenging to diagnose because of the wide range of notch 3 mutations that can cause disease, but a new immunohistochemical technique using a skin biopsy sample appears to be highly sensitive and specific. In a landmark Icelandic study, linkage was established between stroke and a locus on chromosome 5q12 designated STRK1. Association studies continue to identify polymorphisms that predispose to stroke and to markers for cerebrovascular atherosclerosis, such as intima-media thickness. Intense interest now surrounds genes involved in inflammation, including genes that encode for the interleukin-1 receptor antagonist and paraoxonase-1. In the foreseeable future, prevention, diagnosis, and treatment will incorporate genetic data to refine and individualize management of cerebrovascular disease.

The Siblings With Ischemic Stroke Study (SWISS) protocol

BACKGROUND

Family history and twins studies suggest an inherited component to ischemic stroke risk. Candidate gene association studies have been performed but have limited capacity to identify novel risk factor genes. The Siblings With Ischemic Stroke Study (SWISS) aims to conduct a genome-wide scan in sibling pairs concordant or discordant for ischemic stroke to identify novel genetic risk factors through linkage analysis.

METHODS

Screening at multiple clinical centers identifies patients (probands) with radiographically confirmed ischemic stroke and a family history of at least 1 living full sibling with stroke. After giving informed consent, without violating privacy among other family members, the proband invites siblings concordant and discordant for stroke to participate. Siblings then contact the study coordinating center. The diagnosis of ischemic stroke in potentially concordant siblings is confirmed by systematic centralized review of medical records. The stroke-free status of potentially discordant siblings is confirmed by validated structured telephone interview. Blood samples for DNA analysis are taken from concordant sibling pairs and, if applicable, from 1 discordant sibling. Epstein-Barr virus-transformed lymphoblastoid cell lines are created, and a scan of the human genome is planned.

DISCUSSION

Conducting adequately powered genomics studies of stroke in humans is challenging because of the heterogeneity of the stroke phenotype and the difficulty of obtaining DNA samples from clinically well-characterized members of a cohort of stroke pedigrees. The multicentered design of this study is intended to efficiently assemble a cohort of ischemic stroke pedigrees without invoking community consent or using cold-calling of pedigree members.