Prevalence of familial hypercholesterolemia among young north Karelian patients with coronary heart disease: a study based on diagnosis by polymerase chain reaction.

Two deletions of the low density lipoprotein (LDL) receptor gene account for about 90% of the mutations that cause familial hypercholesterolemia (FH) in eastern Finland. The FH-Helsinki mutation deletes exons 16, 17 and a portion of exon 18, while the FH-North Karelia allele is characterized by a deletion of seven nucleotides from exon 6 of the LDL receptor gene. We developed a DNA assay based on the use of polymerase chain reaction (PCR) which simultaneously detects both of these mutations. We have screened 90 young (< 45 years) eastern Finns with symptomatic coronary heart disease (CHD) for the presence of these FH genes. One or the other of the mutations was present in 4 out of 55 survivors of acute myocardial infarction (AMI) and 4 out of 35 patients with angina pectoris (AP), but in none of 50 healthy controls of similar age. These data show a relatively high prevalence of confirmed FH in young CHD patients (AMI and MI combined: 8/90, or 9%), and also demonstrate the feasibility of PCR techniques in diagnosis of FH among populations with enrichment of specific types of LDL receptor gene mutations.