The relevance of checking population allele frequencies and Hardy–Weinberg Equilibrium in genetic association studies: The case of SLC6A4 5-HTTLPR polymorphism in a Chinese Han Irritable Bowel Syndrome association study

2014 ◽  
Vol 162 (1) ◽  
pp. 276-278 ◽  
Author(s):  
Valerio Napolioni
Keyword(s):  
Irritable Bowel Syndrome ◽  
Association Study ◽  
Genetic Association ◽  
Association Studies ◽  
Genetic Association Studies ◽  
Chinese Han ◽  
Weinberg Equilibrium ◽  
Hardy Weinberg Equilibrium ◽  
Irritable Bowel ◽  
Syndrome Association

scholarly journals Power Estimation for Gene-Longevity Association Analysis Using Concordant Twins

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Qihua Tan ◽  
Jing Hua Zhao ◽  
Torben Kruse ◽  
Kaare Christensen
Keyword(s):  
Association Study ◽  
Genetic Association ◽  
Association Analysis ◽  
Statistical Power ◽  
Association Studies ◽  
Genetic Association Studies ◽  
Small Sample ◽  
Identical Twins ◽  
Human Longevity ◽  
Sample Sizes

Statistical power is one of the major concerns in genetic association studies. Related individuals such as twins are valuable samples for genetic studies because of their genetic relatedness. Phenotype similarity in twin pairs provides evidence of genetic control over the phenotype variation in a population. The genetic association study on human longevity, a complex trait that is under control of both genetic and environmental factors, has been confronted by the small sample sizes of longevity subjects which limit statistical power. Twin pairs concordant for longevity have increased probability for carrying beneficial genes and thus are useful samples for gene-longevity association analysis. We conducted a computer simulation to estimate the power of association study using longevity concordant twin pairs. We observed remarkable power increases in using singletons from longevity concordant twin pairs as cases in comparison with cases of sporadic proband. A similar power would require doubled sample sizes for fraternal twins than for identical twins who are concordant for longevity suggesting that longevity concordant identical twins are more efficient samples than fraternal twins. We also observed an approximate of 2- to 3-fold increase in sample sizes needed for longevity cutoff at age 90 as compared with that at age 95. Overall, our results showed high value of twins in genetic association studies on human longevity.

scholarly journals Association Study of Serotonin Transporter SLC6A4 Gene with Chinese Han Irritable Bowel Syndrome

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e84414 ◽  
Author(s):  
Jing Yuan ◽  
ChuanYuan Kang ◽  
Min Wang ◽  
Qiang Wang ◽  
PeiKai Li ◽  
...  
Keyword(s):  
Irritable Bowel Syndrome ◽  
Association Study ◽  
Serotonin Transporter ◽  
Chinese Han ◽  
Irritable Bowel

A genetic association study of 5-HTT LPR and GN?3 C825T polymorphisms with irritable bowel syndrome

2007 ◽  
Vol 19 (6) ◽  
pp. 465-470 ◽  
Author(s):  
y. a. saito ◽  
g. r. locke ◽  
j. m. zimmerman ◽  
g. holtmann ◽  
j. p. slusser ◽  
...  
Keyword(s):  
Irritable Bowel Syndrome ◽  
Association Study ◽  
Genetic Association ◽  
Genetic Association Study ◽  
Irritable Bowel

scholarly journals Statistical significance in genetic association studies

2010 ◽  
Vol 33 (5) ◽  
pp. 266 ◽  
Author(s):  
Hui-Qi Qu ◽  
Matthew Tien ◽  
Constantin Polychronakos
Keyword(s):  
Association Study ◽  
Genetic Association ◽  
Genome Wide Association Study ◽  
Association Studies ◽  
Statistical Significance ◽  
Genetic Association Studies ◽  
Positive Association ◽  
Sampling Bias ◽  
Genetic Associations ◽  
Candidate Loci

Clinical & Investigative Medicine (CIM) is receiving an increasing number of reports of candidate-based association studies. The track record of such studies in the past has been poor: numerous genetic associations reported from candidate gene studies have not been replicated in later studies. The rise of the genome-wide association study (GWAS) is changing this situation. A well-designed GWAS may identify a number of candidate loci without bias by screening the whole human genome. Validating and fine-mapping the candidate loci from GWAS are required to clarify the genetic mechanisms. Thus, a candidate-based association study has become a well-directed effort, instead of searching for a needle in a haystack. In the post-GWAS era, exponential growth of candidate-based genetic association studies is expected. A pressing issue accompanying this new trend is the assessment of the validity of an association study. In this editorial, we illustrate the major cause of false positive association from random sampling bias by an empirical example, and emphasize the application of the probability theory in assessing the validity of a genetic association study.

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