Family-Based Study Designs

2008 ◽  
pp. 19-28 ◽  
Author(s):  
Audrey Schnell ◽  
John Witte
Keyword(s):  
Family Based ◽  
Study Designs

scholarly journals Case–Parent Trio Studies in Cleft Lip and Palate

2020 ◽  
Vol 07 (03) ◽  
pp. 075-079
Author(s):  
Mahamad Irfanulla Khan ◽  
Prashanth CS
Keyword(s):  
Genetic Variants ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Association Studies ◽  
Geographical Location ◽  
Genetic Association Studies ◽  
Population Based ◽  
Genome Wide Association Studies ◽  
Family Based ◽  
Study Designs

AbstractCleft lip with or without cleft palate (CL/P) is one of the most common congenital malformations in humans involving various genetic and environmental risk factors. The prevalence of CL/P varies according to geographical location, ethnicity, race, gender, and socioeconomic status, affecting approximately 1 in 800 live births worldwide. Genetic studies aim to understand the mechanisms contributory to a phenotype by measuring the association between genetic variants and also between genetic variants and phenotype population. Genome-wide association studies are standard tools used to discover genetic loci related to a trait of interest. Genetic association studies are generally divided into two main design types: population-based studies and family-based studies. The epidemiological population-based studies comprise unrelated individuals that directly compare the frequency of genetic variants between (usually independent) cases and controls. The alternative to population-based studies (case–control designs) includes various family-based study designs that comprise related individuals. An example of such a study is a case–parent trio design study, which is commonly employed in genetics to identify the variants underlying complex human disease where transmission of alleles from parents to offspring is studied. This article describes the fundamentals of case–parent trio study, trio design and its significances, statistical methods, and limitations of the trio studies.

Genetic association of G896A polymorphism of TLR4 gene in leprosy through family-based and case-control study designs

2013 ◽  
Vol 107 (12) ◽  
pp. 777-782 ◽  
Author(s):  
N. C. Suryadevara ◽  
V. S. K. Neela ◽  
S. Kovvali ◽  
S. S. Pydi ◽  
S. Jain ◽  
...  
Keyword(s):  
Genetic Association ◽  
Case Control Study ◽  
Case Control ◽  
Tlr4 Gene ◽  
Family Based ◽  
Study Designs ◽  
Control Study

scholarly journals Statistical challenges for genome-wide association studies of suicidality using family data

2010 ◽  
Vol 25 (5) ◽  
pp. 307-309 ◽  
Author(s):  
J. Lasky-Su ◽  
C. Lange
Keyword(s):  
Association Studies ◽  
Statistical Tests ◽  
Genetic Association Studies ◽  
Genetic Effect ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Genetic Etiology ◽  
Genome Wide ◽  
Family Based ◽  
Study Designs

AbstractThe etiology of suicide is complex in nature with both environmental and genetic causes that are extremely diverse. This extensive heterogeneity weakens the relationship between genotype and phenotype and as a result, we face many challenges when studying the genetic etiology of suicide. We are now in the midst of a genetics revolution, where genotyping costs are decreasing and genotyping speed is increasing at a fast rate, allowing genetic association studies to genotype thousands to millions of SNPs that cover the entire human genome. As such, genome-wide association studies (GWAS) are now the norm. In this article we address several statistical challenges that occur when studying the genetic etiology of suicidality in the age of the genetics revolution. These challenges include: (1) the large number of statistical tests; (2) complex phenotypes that are difficult to quantify; and (3) modest genetic effect sizes. We address these statistical issues in the context of family-based study designs. Specifically, we discuss several statistical extensions of family-based association tests (FBATs) that work to alleviate these challenges. As our intention is to describe how statistical methodology may work to identify disease variants for suicidality, we avoid the mathematical details of the methodologies presented.

scholarly journals Statistical challenges in genetic association analyses: Populationbased versus family-based studies

2019 ◽  
Vol 79 (01S) ◽  
Author(s):  
Saurabh Ghosh ◽  
Tanushree Haldar
Keyword(s):  
Genetic Association ◽  
Complex Traits ◽  
Disease Status ◽  
Population Based ◽  
Association Tests ◽  
Association Analyses ◽  
Advantages And Disadvantages ◽  
Tests Of Association ◽  
Family Based ◽  
Study Designs

Genetic association tests provide clues on chromosomal locations of putative genes underlying complex traits, both qualitative (such as disease status) and quantitative (such as measurable precursors of clinical outcomes). One can adopt either a population-based or a family-based study design to generate genotype and phenotype data necessary to carry out the tests of association. In this article, we provide an overview of the two contrasting study designs, the statistical issues pertaining to each of these study designs as well as their relative advantages and disadvantages. We also outline the current statistical challenges in interpreting association findings in the presence of population stratification and in carrying out appropriate comparisons of the powers of the association tests based on the two study designs.

scholarly journals Towards non-conventional methods of designing register-based epidemiological studies: An application to pediatric research

2017 ◽  
Vol 45 (17_suppl) ◽  
pp. 30-35 ◽  
Author(s):  
Tong Gong ◽  
Bronwyn Brew ◽  
Arvid Sjölander ◽  
Catarina Almqvist
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Epidemiological Studies ◽  
Case Control ◽  
Observational Research ◽  
Advantages And Disadvantages ◽  
Study Population ◽  
Family Based ◽  
Study Designs ◽  
Residual Confounding

Aims: Various epidemiological designs have been applied to investigate the causes and consequences of fetal growth restriction in register-based observational studies. This review seeks to provide an overview of several conventional designs, including cohort, case-control and more recently applied non-conventional designs such as family-based designs. We also discuss some practical points regarding the application and interpretation of family-based designs. Methods: Definitions of each design, the study population, the exposure and the outcome measures are briefly summarised. Examples of study designs are taken from the field of low birth-weight research for illustrative purposes. Also examined are relative advantages and disadvantages of each design in terms of assumptions, potential selection and information bias, confounding and generalisability. Kinship data linkage, statistical models and result interpretation are discussed specific to family-based designs. Results: When all information is retrieved from registers, there is no evident preference of the case-control design over the cohort design to estimate odds ratios. All conventional designs included in the review are prone to bias, particularly due to residual confounding. Family-based designs are able to reduce such bias and strengthen causal inference. In the field of low birth-weight research, family-based designs have been able to confirm a negative association not confounded by genetic or shared environmental factors between low birth weight and the risk of asthma. Conclusions: We conclude that there is a broader need for family-based design in observational research as evidenced by the meaningful contributions to the understanding of the potential causal association between low birth weight and subsequent outcomes.

scholarly journals Evaluation of gene-based family-based methods to detect novel genes associated with familial late onset Alzheimer disease

2018 ◽  
Author(s):  
Maria Victoria Fernández ◽  
John Budde ◽  
Jorge Del-Aguila ◽  
Laura Ibañez ◽  
Yuetiva Deming ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Rare Variants ◽  
Late Onset ◽  
Methodological Approach ◽  
Case Control Studies ◽  
High Confidence ◽  
Novel Genes ◽  
Practical Examination ◽  
Family Based ◽  
Study Designs

AbstractGene-based tests to study the combined effect of rare variants towards a particular phenotype have been widely developed for case-control studies, but their evolution and adaptation for family-based studies, especially for complex incomplete families, has been slower. In this study, we have performed a practical examination of all the latest gene-based methods available for family-based study designs using both simulated and real datasets. We have examined the performance of several collapsing, variance-component and transmission disequilibrium tests across eight different software and twenty-two models utilizing a cohort of 285 families (N=1,235) with late-onset Alzheimer disease (LOAD). After a thorough examination of each of these tests, we propose a methodological approach to identify, with high confidence, genes associated with the studied phenotype with high confidence and we provide recommendations to select the best software and model for family-based gene-based analyses. Additionally, in our dataset, we identified PTK2B, a GWAS candidate gene for sporadic AD, along with six novel genes (CHRD, CLCN2, HDLBP, CPAMD8, NLRP9, MAS1L) as candidates genes for familial LOAD.

Association study of BDNF and DRD3 genes in schizophrenia diagnosis using matched case–control and family based study designs

2010 ◽  
Vol 34 (8) ◽  
pp. 1412-1418 ◽  
Author(s):  
Clement C. Zai ◽  
Mirko Manchia ◽  
Vincenzo De Luca ◽  
Arun K. Tiwari ◽  
Alessio Squassina ◽  
...  
Keyword(s):  
Association Study ◽  
Case Control ◽  
Matched Case ◽  
Family Based ◽  
Study Designs

Effect of pomegranate fruit supplementation on performance and various markers in athletes and active subjects: a systematic review

2019 ◽  
pp. 1-15
Author(s):  
Alicja Urbaniak ◽  
Anna Skarpańska-Stejnborn
Keyword(s):  
Vessel Diameter ◽  
Whole Body ◽  
Double Blind Study ◽  
Double Blind ◽  
Physically Active ◽  
Highly Active ◽  
Body Strength ◽  
Rate Of Increase ◽  
Study Designs ◽  
Pomegranate Fruit

Abstract. The aim of the study was to review recent findings on the use of POM supplements in athletes of various disciplines and physically active participants. Eleven articles published between 2010 and 2018 were included, where the total number of investigated subjects was 176. Male participants constituted the majority of the group (n = 155), as compared to females (n = 21). 45% of research described was conducted on athletes, whereas the remaining studies were based on highly active participants. Randomised, crossover, double-blind study designs constituted the majority of the experimental designs used. POM supplementation varied in terms of form (pills/juice), dosage (50 ml–500 ml) and time of intervention (7 days–2 months) between studies. Among the reviewed articles, POM supplementation had an effect on the improvement of the following: whole body strength; feeling of vitality; acute and delayed muscle fatigue and soreness; increase in vessel diameter; blood flow and serum level of TAC; reduction in the rate of increase for HR, SBP, CK and LDH; support in the recovery of post-training CK, LDH, CRP and ASAT to their baseline levels; reduction of MMP2, MMP9, hsCRP and MDA; and increased activity of antioxidant enzymes (glutathione peroxidase and superoxide dismutase). In the majority of reviewed articles POM supplementation had a positive effect on a variety of parameters studied and the authors recommended it as a supplement for athletes and physically active bodies.

Patientenbezogene Komplexität in der Pflege – Kollektive Case Studies im Akutspital

Pflege ◽  
2018 ◽  
Vol 31 (5) ◽  
pp. 237-244 ◽  
Author(s):  
Caroline Gurtner ◽  
Rebecca Spirig ◽  
Diana Staudacher ◽  
Evelyn Huber
Keyword(s):  
Case Studies ◽  
Study Designs

Zusammenfassung. Hintergrund: Die patientenbezogene Komplexität der Pflege ist durch die Merkmale „Instabilität“, „Unsicherheit“ und „Variabilität“ definiert. Aufgrund der reduzierten Aufenthaltsdauer und der steigenden Zahl chronisch und mehrfach erkrankter Personen erhöht sich die Komplexität der Pflege. Ziel: In dieser Studie untersuchten wir das Phänomen patientenbezogener Komplexität aus Sicht von Pflegefachpersonen und Pflegeexpertinnen im Akutspital. Methode: Im Rahmen eines kollektiven Case-Study-Designs schätzten Pflegefachpersonen und Pflegeexpertinnen die Komplexität von Pflegesituationen mit einem Fragebogen ein. Danach befragten wir sie in Einzelinterviews zu ihrer Einschätzung. Mittels Within-Case-Analyse verdichteten wir die Daten induktiv zu Fallgeschichten. In der Cross-Case-Analyse verglichen wir die Fallgeschichten hinsichtlich deduktiv abgeleiteter Merkmale. Ergebnisse: Die Ausprägung der Komplexität hing in den vier Cases im Wesentlichen davon ab, ob klinische Probleme kontrollierbar und prognostizierbar waren. Je nach individuellen Ressourcen der Patientinnen und Patienten stieg bzw. sank die Komplexität. Schlussfolgerungen: Komplexe Patientensituationen fordern von Pflegefachpersonen Fachwissen, Erfahrung, kommunikative Kompetenzen sowie die Fähigkeit zur Reflexion. Berufsanfänger und Berufsanfängerinnen werden zur Entwicklung dieser Fähigkeiten idealerweise durch erfahrene Berufskolleginnen oder -kollegen unterstützt und beraten.

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