The study was renewed in fiscal year 1996 to determine the contribution of polymorphic variation in nine candidate genes involved in lipid metabolism [APO(a), APOD, hepatic lipase (HL), cholesteryl ester transfer protein (CETP), LDL receptor related protein (LRP), 3- hydroxy-3 methyl glutryl-coenzyme A (HMG COA), VLDL-receptor, Lecithin cholesterol acyletransferase (LCAT) and paraoxonase (PON)] in determining quantitative lipoprotein-lipid levels in Hispanics and non-Hispanic Whites of the San Luis Valley, Colorado. The study also determined the molecular basis of the functional mutation in the lipoprotein lipase (LPL) gene which is associated with plasma triglyceride and HDL cholesterol variations. The objectives were achieved by fulfilling the following specific aims: 1) by PCR, DNA sequencing and SSCP analyses, all coding exons and putative regulatory elements in the LPL gene of individuals who were homozygous for the HindIII restriction site to detect nucleotide changes in the coding region which affected directly triglycerides and HDL-cholesterol levels werescreened, in vitro mutagenesis and expression studies were conducted to confirm which of the putative functional mutations was the actual functional mutation; 2) genetic variations in genes coding for CETP, HL, LRP, APOD, HMG COA, VLDL-receptor, LCAT and PON were identified by PCR or standard Southern blotting techniques, and the impact of individual polymorphisms and the joint impact of polymorphisms at different loci (genotype-genotype interaction) in determining quantitative lipoprotein-lipid levels in Hispanics and non-Hispanic whites were estimated; and 3) the distribution of APO(a) kringle 4 and pentanucleotide polymorphisms were determined by SDS-agarose gel electrophoresis and PCR, respectively, and LP(a) levels were quantified by enzyme-linked immunosorbent assay, and the correlation between APO(a) polymorphisms and LP(a) levels were investigated.