Cuchel Marina, Wolfe Megan L, deLemos Andrew S, Rader Daniel J
Department of Medicine, University of Pennsylvania, School of Medicine, 654 BRB II/III, 421 Curie Blvd, Philadelphia, PA 19104, USA.
Atherosclerosis. 2002 Jul;163(1):169-74. doi: 10.1016/s0021-9150(01)00769-9.
Cholesteryl ester transfer protein (CETP) mediates the exchange of cholesteryl ester for triglyceride between high density lipoprotein (HDL) and very low density lipoprotein. The B2 allele of the TaqIB polymorphism located in the first intron of the CETP gene occurs with an allele frequency of about 0.40 in Caucasians and is associated with decreased CETP levels and activity and with higher HDL-cholesterol (HDL-C) levels in this racial group. We hypothesized that the higher levels of HDL-C seen in African Americans compared with Caucasians could be in part explained by a higher frequency of the TaqI B2 allele. We determined the distribution of this polymorphism in a total of 395 African Americans and 362 Caucasian ascertained as two independent cohorts: one of healthy volunteers (NORM) and the other of patients undergoing cardiac catheterization (CATH). Of the 244 NORM-African Americans studied, 56% were B1B1, 37% B1B2 and 7% B2B2, compared with the 224 NORM-Caucasians of which 33% were B1B1, 45% B1B2 and 22% B2B2. In the CATH-African American group (n=151) 51% were B1B1, 41% B1B2 and 8% B2B2 compared with 35% CATH-Caucasians B1B1, 54% B1B2 and 11% B2B2. The frequency of the B2 allele in the Caucasian subjects in both cohorts was similar to that reported in the literature. The frequency of the B2 allele was significantly lower in African Americans than in Caucasians in the NORM group (0.26 vs 0.44; chi(2)=36.5, P<0.001) and in the CATH group (0.28 vs 0.38, chi(2)=4.7, P=0.01). Carriers of the B2 allele had higher HDL-C levels compared with B1B1 subjects in Caucasians (NORM: 57 vs 53 mg/dl, P=0.035; CATH: 47 vs 42 mg/dl, P=0.049) and in CATH-African Americans (48 vs 43 mg/dl, P=0.028), but not in NORM-African Americans (55 vs 54 mg/dl, P=0.494). There were no other significant associations between this polymorphism and other lipids and lipoproteins in the subjects studied. These results suggest that, in contrast to our hypothesis, the B2 allele of the TaqIB polymorphism is less frequent in African Americans compared with Caucasians and that this polymorphism is unlikely to contribute to the higher levels of HDL-C reported in the African American population.
胆固醇酯转运蛋白（CETP）介导高密度脂蛋白（HDL）和极低密度脂蛋白之间胆固醇酯与甘油三酯的交换。位于CETP基因第一内含子的TaqIB多态性的B2等位基因在白种人中的等位基因频率约为0.40，并且与该种族群体中CETP水平和活性降低以及较高的高密度脂蛋白胆固醇（HDL-C）水平相关。我们推测，与白种人相比，非裔美国人中较高的HDL-C水平可能部分归因于TaqI B2等位基因的较高频率。我们确定了总共395名非裔美国人和362名白种人（作为两个独立队列）中这种多态性的分布：一个是健康志愿者队列（NORM），另一个是接受心脏导管插入术的患者队列（CATH）。在244名接受研究的NORM-非裔美国人中，56%为B1B1，37%为B1B2，7%为B2B2；相比之下，224名NORM-白种人中，33%为B1B1，45%为B1B2，22%为B2B2。在CATH-非裔美国人组（n = 151）中，51%为B1B1，41%为B1B2，8%为B2B2；相比之下，CATH-白种人中35%为B1B1，54%为B1B2，11%为B2B2。两个队列中的白种人受试者中B2等位基因的频率与文献报道的相似。在NORM组（0.26对0.44；卡方 = 36.5，P < 0.001）和CATH组（0.28对0.38，卡方 = 4.7，P = 0.01）中，非裔美国人中B2等位基因的频率显著低于白种人。与白种人中的B1B1受试者相比，B2等位基因携带者的HDL-C水平更高（NORM组：57对53mg/dl，P = 0.035；CATH组：47对42mg/dl，P = 0.049），在CATH-非裔美国人中也是如此（48对43mg/dl，P = 0.028），但在NORM-非裔美国人中并非如此（55对54mg/dl，P = 0.494）。在所研究的受试者中，这种多态性与其他脂质和脂蛋白之间没有其他显著关联。这些结果表明，与我们的假设相反，与白种人相比，非裔美国人中TaqIB多态性的B2等位基因频率较低，并且这种多态性不太可能导致非裔美国人群体中报道的较高HDL-C水平。
