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Increase in power of transmission‐disequilibrium tests for quantitative traits
Author(s) -
Malkin Ida,
Ginsburg Emil,
Elston Robert C.
Publication year - 2002
Publication title -
genetic epidemiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.301
H-Index - 98
eISSN - 1098-2272
pISSN - 0741-0395
DOI - 10.1002/gepi.10180
Subject(s) - transmission disequilibrium test , offspring , heritability , trait , biology , extreme value theory , statistics , disequilibrium , genetics , locus (genetics) , evolutionary biology , mathematics , haplotype , allele , computer science , gene , medicine , pregnancy , ophthalmology , programming language
Allison ([1997] Am. J. Hum. Genet. 60:676–690) proposed four versions of the transmission‐disequilibrium test (TDT) for quantitative traits when there is extreme‐threshold sampling , i.e., the trios having an offspring trait value between a priori defined thresholds are excluded from the analysis. Keeping intact the ideology and construction of these tests, we propose here an extreme‐offspring design for the trios: for each parent pair of which at least one is heterozygous at a marker locus, the offspring having the most extreme trait value is selected for the trio. Our simulation studies show that the effect of the extreme‐offspring design can be quite substantial (up to 30% increase in test power), and that the increase is greater for smaller values of the association parameter and for traits with smaller heritability: just those cases where the increase in power is especially desirable. Genety. Epidemiol. 23:234–244, 2002. © 2002 Wiley‐Liss, Inc.