The Trp23-Stop and Trp66-Gly mutations in the LDL receptor gene: common causes of familial hypercholesterolemia in Denmark

Mutations in the gene for the low density lipoprotein (LDL) receptor cause the autosomal dominant disease familial hypercholesterolemia (FH), the prevalence of which is about 0.2% in most populations. By PCR-SSCP analysis and direct sequencing, we identified the receptor-negative Trp23-Stop LDL receptor mutation (FH Cincinnati-5) in 10 of 63 FH probands and the receptor-defective Trp66-Gly LDL receptor mutation (FH French Canadian-4) in another 10 of the 63 FH probands. These two mutations thus account for 30% of diagnosed FH families in Denmark. Comparison of the mean lipid concentrations (unadjusted and adjusted for age), including serum total cholesterol and LDL-cholesterol, showed no significant differences between the two groups of FH heterozygote probands (cholesterol: 10.7 mmol/l vs. 10.7 mmol/l) and between the probands and 16 and 22 non-proband family members with the Trp23-stop (cholesterol: 10.1 mmol/l) and Trp66-Gly (cholesterol: 10.7 mmol/l) mutations, respectively.