In studies of traits like hypertension or obesity, information can be lost when arbitary cirteria are used to dichotomize a continous variable to determine ?affection status.? The effect of this loss of information on the power of model-independent tests of linkage and association was evaluated using computer simulation. The Genometric Analysis Simulation Program (G.A.S.P.) was used to simulate a continuous variable with a threshold set to that approximately 5% of the population would be affected. One hundred nuclear families, each with four offspring, were acertained so that at least two offspring were afected in each family. Models considered include: heritabilities from 0 to 0.8, complete and no linkage disequilibrium, and recombination fractions from 0 to 10 cM. The power of four variations of the Haseman-Elston (H-E) sib- pair test for discrete traits and the TDT test were compared to the H-E test for a continous trait. The power of the H-E test for concordantly affected pairs (only) was nearly identical to that of the H-E test for the continuous trait. The TDT test of association was more powerful than the H-E test for continuous traits when there was complete linkage disequilibrium; other the power of this test was only marginally better than the type I error rate

Agency
National Institute of Health (NIH)
Institute
National Human Genome Research Institute (NHGRI)
Type
Intramural Research (Z01)
Project #
1Z01HG000127-01
Application #
6109053
Study Section
Special Emphasis Panel (IDRB)
Project Start
Project End
Budget Start
Budget End
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
National Human Genome Research Institute
Department
Type
DUNS #
City
State
Country
United States
Zip Code