Frequency of cytochrome P450 2C9 allelic variants in the Chinese and French populations

Abstract

Cytochrome P450 2C9 (CYP2C9) is a polymorphic enzyme responsible for the metabolism of different drugs with low therapeutic index such as oral anticoagulants. CYP2C9*2 and CYP2C9*3 are two single nucleotide polymorphic allelic variants. The frequency of these alleles in different ethnic populations is extremely variable. In this study, we compared the frequencies of CYP2C9 allelic variants among 394 Chinese living in Shanghai to 151 French Caucasians living in Paris. The allelic frequencies of CYP2C9 variants of the Chinese and the French subjects were 0.963, 0.001, 0.036 and 0.77, 0.15, 0.08 for CYP2C9*1, CYP2C9*2, CYP2C9*3, respectively. Chinese CYP2C9*3 allelic frequency was twice as lower as the French subjects, but three times higher than Korean (0.036 vs. 0.011). The CYP2C9*2 allele could be detected in only one Chinese subject, whereas it represented the major allelic variant in French Caucasians. The low frequency of the CYP2C9*2 and CYP2C9*3 allelic variants in Chinese subjects does not justify their detection in clinical practice, unlike French Caucasians.

187 Early Post-Traumatic Seizures are Associated with Valproic Acid Plasma Concentrations and UGT1A6/CYP2C9 Genetic Polymorphisms in Patients with Severe Traumatic Brain Injury

“…As mentioned earlier, the antiepileptic effects of VPA requires stable plasma concentrations, which are associated with genetic polymorphisms affecting VPA pharmacokinetics and pharmacodynamics. Compared to previous studies, there were no significant differences in the frequencies of the UGT1A6, UGT2B7, CYP2C9, CYP2C19 genotypes between our observations and other reported Chinese populations [29,[37][38][39]. During the first two days after injury, when plasma concentrations were initially not available, all patients received similar dosages of VPA injection in our study.…”

“…However, the results were not entirely consistent. For example, our findings on UGT1A6 SNPs were supported by two recent publications showing that homozygous carriers of the variant UGT1A6 19T > G, 541A > G and 552A > C allele have relatively low VPA concentrations [39,40]. However, similar results were not achieved in other studies [41].…”

Frequency of CYP2C9 alleles in Koreans and their effects on losartan pharmacokinetics

“…The CYP2C9 allelic variants CYP2C9*2, CYP2C9*3, and CYP2C9*13 code for enzymes with approximately 10%-40%, 5%-15%, and 1%-12% of the activity of CYP2C9*1, respectively [4,10,29] . The CYP2C9*2 allele is the most common variant allele among people of European descent with a frequency of approximately 0.132 [4,9,16,30] . In contrast, the CYP2C9*2 allele is rare in East Asians [3] (Table 3).…”

In Vitro and In Vivo Characterization of 13 CYP2C9 Allelic Variants Found in Chinese Han Population

“…Different populations had different frequencies of CYP2C9*2 and CYP2C9*3. For instance, in Chinese Han population, CYP2C9*1, CYP2C9*2, and CYP2C9*3 had a frequency of 0.963, 0.001, and 0.036 (Yang et al, 2003), whereas in Italian and Ethiopian population, the corresponding frequencies were 0. 8, 0.11, 0.09, and 0.94, 0.04, 0.02 (Scordo et al, 2001), respectively.…”