In 1988, two regular research grants were awarded as part of this multicenter study. The grant at the Southwest Foundation for Biomedical Research determined the genotypes for each subject with respect to restriction fragment length polymorphisms in apolipoprotein and LDL receptor genes using Southern blot analyses of DNA from liver samples sent from each collection center. It also typed the subjects for apo E isoform genotypes using oligonucleotide probes. The grant at Ohio State University correlated 3-D coronary axial geometry and pathology.