CYP3A5*3 and *6 single nucleotide polymorphisms in three distinct Asian populations

Abstract

To determine the frequencies of two functional single nucleotide polymorphisms, CYP3A5*3 and CYP3A5*6, in the CYP3A5 gene in three distinct Asian ethnic groups, namely, the Chinese, Malays and Indians. Single nucleotide polymorphism analyses of CYP3A5*1, *3 and *6 were performed in 296 healthy subjects (108 Chinese, 98 Malays and 90 Indians) using the polymerase chain reaction-restriction fragment length polymorphism method. The *1 allele frequency was 25% in Chinese compared with 40% in Malays and Indians (P=0.001). The *3 allele frequency was also higher in the Chinese population, being 76% versus 60% in the Malays and Indians (P=0.001). The Malays and Indians also had allele frequencies significantly different from Caucasian, Japanese and African-American populations (each P≤0.001) previously published in the literature. The *6 allele was not detected in any the three Asian ethnic groups analysed. These results seem to suggest that genetic polymorphisms in CYP3A5 in Asians, in particular Malays and Indians but also Chinese although to a lesser extent, may be an important genetic contributor to interindividual as well as interethnic differences in clearance of CYP3A substrates.