Abstract
We have used anchored PCR to amplify and sequence 1400bp of the 15th intron of the Low Density Lipoprotein (LDL) receptor gene, and have determined oligonucleotides and conditions for the genotyping of the previously reported Pvull polymorphism. The cutting site (CAGCTG) is created by the transition of a CpG to a TpG within the sequence CAGCCG at a position roughly 600bp 5' from the splice acceptor site of exon 16. Genotype was determined in three populationbased samples of healthy individuals. In a group of 318 men and women from Iceland the frequencies of the Intron-15 T (cutting) allele was 0.23 (95% CI, 0.19-0.28) and was similar in men and women. In two groups of men from England (n=385) and Scotland (n=320), the frequency was similar, being 0.23 (0.19-0.27) and 0.25 (0.22-0.28) respectively. Individuals who were homozygous for the T allele had lower levels oftotal-cholesterol triglycerides and apolipoprotein B, than those with other genotypes, and in the combined group of UK men this effect reached statistical significance; compared to the CIC group, the TIT group had 6% lower cholesterol (p=0.02) and 15% lower triglycerides (p=0.03). The lowering effect associated with the TIT genotype was greater in men who were in the lowest terti Ie of body mass index (<25kg/m2) and for the trait of apoB levels, this genotype x obesity interaction was statistically significant (p=0.01). We thus confirm the association between this allele and lower levels of plasma lipid levels previously reported. The availability of a PCR-based method to detect this polymorphism will facilitate further investigation of the impact of LDL-receptor gene variation in determining lipid levels.