title: How do homozygous parents affect TDT as a test for association?
abstract: The traditional transmission disequilibrium test (TDT) (Spielman et al., 1993) is a powerful test for association only in the presence of linkage. Since allele transmissions from homozygous parents do not carry any information on linkage, the TDT statistic uses data only on heterozygous parents. However, homozygous parents carry information on association between alleles at a marker locus and a disease locus. In this article, we explore whether inclusion of homozygous parents increases the power to detect association. The resultant test statistic follows a chi(2) distribution with 2 degrees of freedom. Monte-Carlo simulations are included to compare the performance of this test with the traditional TDT under different disease models.
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63110-1093, USA. saurabh@sikver.wustl.edu
authors.forename: Saurabh
authors.initials: S
authors.lastname: Ghosh
authors.forename: Theodore
authors.initials: T
authors.lastname: Reich
mesh_terms: D000483:Alleles; D016009:Chi-Square Distribution; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D015810:Linkage Disequilibrium; D009010:Monte Carlo Method; D010290:Parents