International Journal of Cardiology 90 (2003) 269–273 www.elsevier.com / locate / ijcard A1/A2 V ariation of the platelet glycoprotein IIIa PI allele frequencies in the three ethnic groups of Singapore a b a a b b, * Jimmy Lim , Suman Lal , Kenneth C. Ng , Kheng-Siang Ng , Nilmani Saha , Chew-Kiat Heng a Tan Tock Seng Hospital, Singapore, Singapore b Department of Paediatrics, National University of Singapore,5 Lower Kent Ridge Road, Singapore 119074, Singapore Received 20 April 2002; received in revised form 21 September 2002; accepted 3 November 2002 Abstract Background: Polymorphisms of the glycoprotein IIIa receptor have been shown to be associated with differences in platelet A2 aggregability. The PI variant of the polymorphism has been reported to be an inherited risk factor for acute coronary events. Although the allele frequency of this polymorphism is well documented in Caucasian populations, studies involving Asian Indians, Malays and Chinese are lacking. We studied 706 random male individuals to determine the genotypic distribution of this polymorphism in Singapore. Methods: Male subjects included in this study were drawn from those undergoing routine annual medical examinations offered by their employers. Venous blood was obtained from these patients after an overnight fast and from which genomic DNA was extracted. Genotyping was carried out by polymerase chain reaction (PCR) followed by digestion with restriction enzyme Nci I. Personal and family medical history of the subjects were also taken. Results: The genotype distribution of the individuals studied was in accordance to a A2 population at Hardy Weinberg equilibrium. The frequency of the PI allele was 0.1, 0.01 and 0.01 in the Indians, Malays and Chinese, A2 respectively. The differences in frequencies of the PI variant are significant among different ethnic groups ( P,0.001 for Indians vs. A2 Chinese and Indians vs. Malays). Conclusions: We observed a significantly higher frequency of the PI allele among Indians relative to the Chinese and Malays in Singapore. The effect of this genotype may partially explain the higher rate of ischaemic heart disease seen among Indians compared to the Chinese and Malay ethnic groups.  2003 Elsevier Ireland Ltd. All rights reserved. Keywords: Ethnic variation; Ischaemic heart disease; Coronary artery disease 1. Introduction Singapore are at a higher risk of developing coronary artery disease (CAD) compared to their other ethnic Singapore is a tropical island nation with a land counterparts. In the Singapore Cardiovascular Cohort 2 area of 648 km . The people of Singapore are from Study, Lee et al. [1] found that Indian males had the diverse ethnic origins, with the majority comprising highest risk of developing CAD with a hazard ratio of Chinese, Malays and Indians. The Chinese make up 3.1 when compared to Chinese and 3.4 when com- the majority of the population in Singapore, account- pared to Malays. In another study by Hughes et al. ing for 77%, while the Malays account for 14% and [2], Indians in Singapore had higher mortality from the Indians account for 8%. CAD when compared to their Chinese and Malay Numerous studies have shown that Indians in counterparts. The age standardized relative risks of Indians when compared to Chinese males was 3.8 and 3.4 for females [2]. The higher mortality could *Corresponding author. Tel.: 165-6772-5708; fax: 165-6774-2796. E-mail address: paehck@nus.edu.sg (C.K. Heng). not be explained by risk factors such as cigarette 0167-5273 / 03 / $ – see front matter  2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016 / S0167-5273(02)00567-3