Abstract
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.
Original language | English |
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Pages (from-to) | 234-244 |
Number of pages | 11 |
Journal | Genetic Epidemiology |
Volume | 23 |
Issue number | 3 |
DOIs | |
State | Published - Oct 2002 |
Keywords
- Extreme sampling
- Quantitative traits
- TDT power