Objective To examine the relationship between apolipoprotein E （Apo E） gene polymorphism and risk of coronary artery disease （CAD）

analyzing association of polymorphism with classical risk factors. Methods A total of 124 patients （including 84 Han population and 40 Uygur population） with angiographically verified CAD or myocardial infarction were prospectively evaluated. Data referring to hypertension

diabetes

and tobacco consump-tion were recorded. The levels of total cholesterol （TC）

high density lipoprotein （HDL） cholesterol

Apo A1 and B

and triglycerides （TG） were determined. DNA was obtained from 124 patients and 70 controls. In order to determine Apo E genotypes

DNA was PCR amplified and digested with HhaI. The genetic polymorphism of Apo E is due to three common alleles

epsilon（ε） 2

ε3

ε4

at a single autosomal gene locus. These alleles determine the six phenotypes E2/2

E3/3

E4/4

E4/2

E4/3

and E3/2. Results In Uygur population

the frequency of the ε2

ε3

and ε4 was 0.155

0.648

and 0.197 respectively. In Han po-pulation

the frequency of the ε2

ε3

and ε4 was 0.081

0.772

and 0.146 respectively. In the patient group

the frequency of the ε2

ε3

and ε4was 0.060

0.758

and 0.182 respectively. In the control group

the frequency of the ε2

ε3

and ε4 was 0.193

0.671

and 0.136 respectively. ε2 frequency of Uygur’ patients and controls was 0.050 and 0.290 respectively. Serum low density lipoprotein （LDL） cholesterol

TC

and TG values tended to decrease from the Apo E-4 phenotypes to Apo E-2 phenotypes. When deletion polymorphism of ε2 was compared with the common risk factors for CAD

its risk ratio （RR） is 4.38. Conclusions These studies confirm and find that Apo E phenotype distribution in Uygur population differs significantly from that in Han population in Xinjiang. CAD patients have significantly lower ε2 allele and slightly higher ε3 or ε4 allele frequency than controls

especially in Uygur population. It shows protective effects of ε2 on CAD.