Open AccessThe power of the Transmission Disequilibrium Test in the presence of population stratification
Author(s) -
Ronnie Sebro,
John Rogus
Publication year - 2010
Publication title -
european journal of human genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.587
H-Index - 125
eISSN - 1476-5438
pISSN - 1018-4813
DOI - 10.1038/ejhg.2010.57
Subject(s) - population stratification , disequilibrium , population , biology , transmission disequilibrium test , statistics , hardy–weinberg principle , type i and type ii errors , linkage disequilibrium , genetics , demography , mathematics , allele , allele frequency , haplotype , genotype , medicine , gene , single nucleotide polymorphism , ophthalmology , sociology
The Transmission Disequilibrium Test (TDT) is a family-based test for association based on the rate of transmission of alleles from heterozygous parents to affected offspring, and has gained popularity as this test preserves the Type I error rate. Population stratification results in a decreased number of heterozygous parents compared to that expected assuming Hardy-Weinberg Equilibrium (Wahlund Effect). We show that population stratification changes the relative proportion of the informative mating types. The decrease in the number of heterozygous parents and the change in the relative proportion of the informative mating types result in significant changes to the sample sizes required to achieve the power desired. We show examples of the changes in sample sizes, and provide an easy method for estimating TDT sample sizes in the presence of population stratification. This method potentially aids in reducing the number of false-negative association studies.