Genetic analysis of drug metabolizing phase-I enzymes CYP3A4 in Tibetan populations.

The enzymatic activity of CYP3A4 results in broad interindividual variability in response to certain pharmacotherapies. The present study aimed to screen Tibetan volunteers for CYP3A4 genetic polymorphisms. Previous research has focussed on Han Chinese patients, while little is known about the genetic variation of CYP3A4 in the Tibetan populations. Here, we adopted DNA sequencing to investigate the promoter, exons and surrounding introns, and 3'-untranslated region of the CYP3A4 gene in 96 unrelated healthy Tibetan individuals.We identified 20 different CYP3A4 polymorphisms in the Tibetan population, including two novel variants (21824 A>G and 15580 G>C). In addition, we also determined the allele frequencies of CYP3A4*1A and CYP3A4*1H were 82.29% and 28.13%, respectively. CYP3A4*1P and *1G were relatively rare with frequencies of only 1.04% and 0.52%, respectively. Our results provide information on CYP3A4 polymorphisms in Tibetan individuals which may help to optimize pharmacotherapy effectiveness by providing personalized medicine to this ethnic group.