Kasetpong Sutthakhun. Associations of polymorphisms of APO B3'VNTR, APO E and APO A-1 genes in Thai subjects with primary hyperlipidemia and coronary heart disease . Doctoral Degree(Biochemistry). Mahidol University. : Mahidol University, 2007.
Associations of polymorphisms of APO B3'VNTR, APO E and APO A-1 genes in Thai subjects with primary hyperlipidemia and coronary heart disease
Abstract:
To study the impact of apolipoprotein (apo) B 3′VNTR, apo E and apo A-1
polymorphism in 312 Thai people, 103 normolipidemia, 103 hyperlipidemia and 106 CHD
were obtained from Dyslipoproteinemia Clinic and Her Majesty’s Cardiac Centre at Siriraj
Hospital. The aim of this study was to investigate the role of these polymorphisms on lipid
metabolism in primary hyperlipidemic and CHD subjects whose coronary arteries were
evaluated by mean of coronary angiography. The apo B 3′VNTR polymorphism was
investigated using the polymerase chain reaction (PCR) to determine its frequency and
influence on the lipid profile. Fifteen VNTR alleles and 30 genotypes were observed in 312
Thai subjects. The VNTR 35 allele and genotype VNTR 35/35 were observed most frequency
in normolipidemia and hyperlipidemia but in CHD VNTR 37 allele and genotype VNTR
35/39 were the most frequency. Some minor alleles, such as 47, 49, 51, 58 were found only in
hyperlipidemia and CHD and only allele 53 was found in normolipidemia. The hyperlipidemia
were significantly greater frequency of long (VNTR>41 repeats) allele than the
normolipidemia and CHD. Apolipoprotein E (apo E) plays a major role in lipoprotein
metabolism and lipid transport. The study of apo E polymorphisms containing ε2, ε3 and ε4
were analyzed by polymerase chain reaction-restriction fragment length polymorphisms
(PCR-RFLPs). The results of apo ε2, ε3 and ε4 allele frequencies between normolipidemia (ε2
= 0.063, ε3 = 0.87, ε4 = 0.063), hyperlipidemia (ε2 = 0.08, ε3 = 0.76, ε4 = 0.16) and CHD (ε2
= 0.07, ε3 = 0.78, ε4 = 0.15) revealed that the ε4 allele frequencies was significantly higher in
hyperlipidemia and CHD than in normolipidemia. Apolipoprotein A-1 is the major protein
constituent of plasma HDL and plays a crucial role in reverse lipid transport and metabolism.
Numerous investigators reported that apo A-1 is a co-indicator with HDL to predict the
incidence of CHD. The apo A-1 polymorphisms at -75 bp of G→A substitution at promoter
region and +83 bp of C→T substitution at intron 1 on chromosome 11 were analyzed by PCRRFLP.
The results of the frequency of A allele at -75 bp was significantly different among
normolipidemic, hyperlipidemic subjects and CHD patients. The frequency of T allele at +83
bp was not significantly different among normolipidemic, hyperlipidemic subjects and CHD
patients. In addition, the genotype distribution (VNTR >41 repeats) was associated with higher
plasma lipid levels of total cholesterol and triglyceride in Thai population. The apo ε2 was not
associated with lipid levels but ε4 was associated with high level of plasma cholesterol and
LDL-C. For apo A-1 polymorphisms at -75 bp and +83 bp, there was no association with HDL
levels in any groups of this study. Odds ratio was also used to assess the associations of these
polymorphisms to hyperlipidemia and CHD. The results of this study suggested that large
VNTR, apo ε4 and -75 bp of apo A-1 polymorphism associated with hyperlipidemia and CHD
while +83 bp of apo A-1 polymorphism was not associated with hyperlipidemia and CHD.