GENETIC RISK-FACTORS AND ISCHEMIC CEREBROVASCULAR-DISEASE - ROLE OF COMMON VARIATION OF THE GENES ENCODING APOLIPOPROTEINS AND ANGIOTENSIN-CONVERTING ENZYME

DNA polymorphisms in genes encoding apolipoproteins (apo) A-I, C-m, B and E and angiotensin-converting enzyme (ACE) have been proposed to be associated with the risk of coronary artery disease (CAD). We studied whether the same genetic markers would also be associated with the oc currence and extent of atherosclerosis in cervical arteries. DNA sampl es from 234 survivors of stroke or a transient ischaemic attack aged G O pears or less were examined. The presence of atherosclerosis was ass essed using aortic arch angiograms. The SstI polymorphism of apoA-I/C- III gene locus, the XbaI polymorphism of apoB gene, common apoE phenot ypes and the insertion/deletion polymorphism of the ACE gene were anal ysed. The allele frequencies of the apoA-I/C-III, apoB, apoE or ACE ge ne did not differ between the groups with (It = 148) or without (n = 8 5) cervical atherosclerosis. However, when patients with at least one apoE4 allele and one X2 allele of apoB were combined and compared with those without either of them (E2E3 or E3E3 and X1X1), a significant a ssociation with the presence of cervical atherosclerosis was found (P = 0.03). The patients having the E2E3 phenotype had a significantly el evated serum triglyceride level compared with those with the E3E3 phen otype (P = 0.03). Serum high-density lipoprotein (HDL) cholesterol was lower in the patients with the E2E3 phenotype than in those with the E3E3 and E3E4 (P = 0.01 and P = 0.06, respectively). The apoB or ACE g enotypes were not significantly associated with serum lipid or lipopro tein levels. There was no association between the ACE gene polymorphis m and the occurrence of hypertension. In conclusion, the interaction o f common apoB and apoE alleles may increase the risk of atherosclerosi s in cervical arteries.