Relationship between (TTTTA)n gene polymorphism in the apolipoprotein(a) 5' control region and atherosclerotic cerebral infarction in Han nationality of Hubei area

Bo HU; Xin ZHOU; Zhaoxia LI; Guoqiang HONG; Minqi LUO; Zhenyu ZHU

ABSTRACT

BACKGROUND:

Apolipoprotein(a) [Apo(a)] plays some role in promoting the formation of atherosclerotic plaque, and contains pentanucleotide repeats(PNR), which has a key value in genic research and in forecast on the increased risk of early atherosclerosis cerebral infarction (ACI). But the relationship between ACI and Apo(a) PNR in different races needs to be further investigated.

OBJECTIVE:

To investigate the relationship between the Apo(a) PNR polymorphism and ACI.

DESIGN:

A case-control study based on the ACI patients and normal people of Han nationality in Hubei.

SETTING:

Department of Laboratory in a hospital of a university.

PARTICIPANTS:

From February 1998 to March 1999, 82 ACI patients (ACI group) and 153 healthy controls(control group) were selected from the Department of Neurology, Central South Hospital and Yatai Hospital of Wuhan University. All patients were Han nationality in Hubei without any relatives.

METHODS:

Serum lipoprotein(a) [Lp(a) ], total cholesterol(TC), high density lipoprotein cholesterol(HDL-c), low density lipoprotein cholesterol (LDL-c), triglyceride (TG), apolipoprotein A Ⅰ (ApoA Ⅰ) and apolipoprotein B (Apo B) were tested respectively. Meanwhile, the PNR in the 5' control region of the Apo(a) was detected with polymerase chain reaction(PCR) and high voltage polyacrylamide gels electrophoresis. The results were analyzed with controlled analysis.

RESULTS:

The levels of serum Lp(a) [ (239.9 ±225.4) mg/L], TC [(4.76±0.74) nmol/L], TG[(1.74±0.60) mmol/L] and LDL-C [ (2.84 ± 0. 63) mmol/L] were remarkably higher in ACI group than those in control group, which were(133.5 ±97.7) mg/L in serum Lp(a), (4. 29±0.72) mmol/L in TC, (1.05±0.52) mmol/L in TG and(2.84±0.63) mmol/L in LDL-C, however, the level of HDL-C[ (0.88± 0.17) mmol/L] was remarkably lower in ACI group than that in control group [ ( 1.03 ± 0. 35 ) mmol/L], the differences were all significant( t = 3.65to9.18, P ＜ 0.01) . The levels of ApoA Ⅰ [(1.13±0.15) mmol/L,(1.25±0.19) mmol/L] and ApoB[(0.93±0.12) mmol/L, (0.89± 0. 15 ) mmol/L] were no significant difference compared with those in control group. The duplicated frequency of the allele(TTTTA) 5(0. 098) in the ACI was remarkably higher than that in control(0. 026) (x2 = 5.62, P＜ 0. 05), The frequency of the allele(TTTTA) 9 in the ACI(0. 073) was remarkably lower than that in control (0. 213 ) (x2 = 7.83, P ＜ 0.01 ), The frequency of the allele(TTTTA) 5 was also associated with low TC and high Lp(a) levels.

CONCLUSION:

It is suggested that the Apo(a) PNR polymorphism are associated with the susceptibility to ACI, and involved in the development of ACI.