Polymorphic markers of the CYP1B1 (4326C > G), CYP2F1 (c.14_15insC), CYP2J2 (-76G > T), and CYP2S1 (13106C > T and 13255A > G) genes and genetic predisposition to chronic respiratory diseases induced by smoking and occupational factors

The contribution of the polymorphic markers of cytochrome P450 genes to respiratory diseases caused by smoking and occupational factors has been assessed. For this purpose, PCR-RFLP analysis of the CYP1B1 (rs1056836, 4326C > G), CYP2F1 (rs11399890, c.14_15insC), CYP2J2 (rs890293, -76G > T), and CYP2S1 (rs34971233, 13106C > T and rs338583, 13255A > G) gene polymorphisms has been performed. The analysis has shown that the polymorphic variants of the CYP1B1 (rs1056836, 4326C > G) and CYP2F1 (rs11399890, c. 14_15insC) genes may contribute to the development of occupational chronic bronchitis. The proportion of CYP1B1* 1*3 heterozygotes in the group of patients with occupational chronic bronchitis is considerably greater than in the group of healthy workers (69.16% versus 53.29%; chi2 = 5.94, P = 0.02, P(cor) = 0.04, OR = 1.97, the 95% CI is 1.13-3.42). Patients with occupational chronic bronchitis and healthy workers significantly differed from each other in the frequency distribution of the genotypes ofthe CYP2F1 (rs11399890, c.14_15insC) polymorphic marker (chi2 = 6.18, d.f = 2, P = 0.05). The frequency of the wild type/ins heterozygous genotype for the CYP2F1 gene is higher in healthy workers (36.08%) than in patients (22.22%) (chi2 = 5.48, P = 0.02, P(cor) = 0.04, OR = 0.51, the 95% CI is 0.28-0.90). No association has been found between the CYP2J2 (rs890293, -76G > T) or CYP2S1 (rs34971233, 13106C > T, P466L and rs338583, 13255A > G) gene polymorphisms and respiratory diseases.     

CYP1B1 (4326C > G), CYP2F1 (c.14_15insC), CYP2J2 (?76G > T), and CYP2S1 (13106C > T and 13255A > G) polymorphisms and genetic predisposition to chronic respiratory diseases induced by smoking and occupational factors

The contribution of the polymorphic markers of cytochrome P450 genes to respiratory diseases caused by smoking and occupational factors has been assessed. For this purpose, PCR-RFLP analysis of the CYP1B1 (rs1056836, 4326C > G), CYP2F1 (rs11399890, c.14_15insC), CYP2J2 (rs890293, -76G > T), and CYP2S1 (rs34971233, 13106C > T and rs338583, 13255A > G) gene polymorphisms has been performed. The analysis has shown that CYP1B1 (rs1056836, 4326C > G) and CYP2F1 (rs11399890, c.14_15insC) polymorphisms may contribute to the development of occupational chronic bronchitis. The proportion of CYP1B1*1*3 heterozygotes in the group of patients with occupational chronic bronchitis is considerably greater than in the group of healthy workers (69.16% versus 53.29%; χ² = 5.94, p = 0.02, p _cur = 0.04, OR = 1.97, the 95% CI is 1.13–3.42). Patients with occupational chronic bronchitis and healthy workers significantly differed from each other in the CYP2F1 genotypes frequency distribution (rs11399890, c.14_15insC) (χ² = 6.18, d.f. = 2, p = 0.05). CYP2F1 wild type/ins heterozygous genotype frequency is higher in healthy workers (36.08%) than in patients (22.22%) (χ² = 5.48, p = 0.02, p _cur = 0.04, OR = 0.51, the 95% CI is 0.28–0.90). No association has been found between the CYP2J2 (rs890293, −76G > T) or CYP2S1 (rs34971233, 13106C > T, and rs338583, 13255A > G) gene polymorphisms and respiratory diseases.     

A systematic genetic polymorphism analysis of the CYP2C9 gene in four different geographical Han populations in mainland China

While many studies have been focused on CYP2C9*2 and *3 there was a lack of large full gene sequencing on CYP2C9, and this study was designed to fill this gap. We used direct sequencing to systematically screen genetic polymorphisms of the CYP2C9 gene including the 5' -flanking region (2kb), all exons and their adjoining intron regions and the 3' UTR in 400 unrelated healthy Chinese Han volunteers. A total of 27 different CYP2C9 polymorphisms were identified, 3 of which were novel, including one in intron 6, a synonymous variant (1137T>C, Tyr379Tyr), and a deletion mutation in the 3'UTR (1739-1740ATdel), which potentially influences the stability of CYP2C9 mRNA. We identified CYP2C9*1, *2, *3, *8, *11, and *31, of which alleles *8 was identified for the first time in Chinese population while *11 first in Asian. This is the first systematic screening of genetic polymorphisms of CYP2C9 in the Chinese Han population.     

Polymorphisms in the CYP2E1 and GSTM1 Genes as Possible Protection Factors for Leprosy Patients

Background

The CYP2E1 and GSTM1 genes encode metabolic enzymes that have key functions in drug modification and elimination.

Methodology/Principal Findings

We investigated the possible effects of CYP2E1 and GSTM1 polymorphisms in 71 leprosy patients and in 110 individuals from the general population. The GSTM1*0 null allele and INDEL CYP2E1*1D mutant genotypes were analyzed by conventional PCR, while CYP2E1 SNPs (1053C>T, 1293G>C and 7632T>A) were determined by RT-PCR. In leprosy patients, the GSTM1*0 and CYP2E1*5 alleles and the combined alleles GSTM1*0/CYP2E1*6 and GSTM1*0/CYP2E1*5 were significantly related to a baciloscopic index (BI) (BI<3), while the CYP2E1*6 allele was related to a better clinical evolution in the leprosy spectrum.

Conclusions/Significance

Therefore, GSTM1*0, CYP2E1*5 and CYP2E1*6 may be possible protection factors for leprosy patients.     

Effects of SNPs (CYP1B1*2 G355T,CYP1B1*3 C4326G,and CYP2E1*5 G-1293C), Smoking,and Drinking on Susceptibility to Laryngeal Cancer among Han Chinese

Purpose

This study was conducted to explore the effects of genetic polymorphisms (CYP1B1*2 G355T, CYP1B1*3 C4326G, and CYP2E1*5 G-1293C) and environmental factors (smoking and drinking) on susceptibility to laryngeal cancer in a Han Chinese study group.

Methods

This case-control study included 552 Han Chinese patients diagnosed with laryngeal cancer and 666 healthy control subjects of the same ethnicity, similar age, and gender. Genetic polymorphisms were examined using multi-PCR and Matrix Assisted Laser Desorption Ionization - Time of Flight (MALDI-TOF MS) methodology. The association of these genetic and environmental factors with susceptibility to laryngeal cancer was evaluated using a statistical approach.

Results

The frequencies of all three polymorphisms in the patient cohort were significantly different from those in the control cohort. Compared to the control cohort, carriers of variant alleles of CYP1B1*2 355T and CYP2E1*5 -1293C showed a higher risk for developing laryngeal cancer (for CYP1B1*2 355T, adjusted OR = 2.657, P <0.001; for CYP2E1*5 -1293C, adjusted OR = 1.938, P <0.001), while carriers of mutation allele CYP1B1*3 4326G showed a lower risk (adjusted OR = 0.562, P <0.001). Joint effects of these polymorphisms were observed. When compared to haplotype G₃₅₅C₄₃₂₆G₋₁₂₉₃, haplotypes T₃₅₅C₄₃₂₆G₋₁₂₉₃ (adjusted OR = 1.809, P <0.001), G₃₅₅C₄₃₂₆C₋₁₂₉₃ (adjusted OR = 1.644, P = 0.044), and T₃₅₅C₄₃₂₆C₋₁₂₉₃ (adjusted OR = 3.104, P <0.001) were associated with a significantly higher laryngeal cancer risk. The adjusted ORs for non-smokers, non-drinkers, smokers, and drinkers with the GT/TT genotype at CYP1B1*2 G355T were 2.190 (P = 0.006), 2.008 (P = 0.001), 5.875 (P <0.001), and 4.518 (P <0.001), respectively.

Conclusions

CYP1B1*2 355T and CYP2E1*5 -1293C are associated with an increased laryngeal cancer risk, while CYP1B1*3 4326G is associated with a decreased risk. These polymorphisms showed joint effects on laryngeal cancer risk. Smoking and drinking showed collaborative effects with two high risk alleles (CYP1B1*2 355T and CYP1B1*3 4326G) for promoting laryngeal cancer risk.     

Cytochrome P450 2D6 variants in a Caucasian population: allele frequencies and phenotypic consequences.

Cytochrome P450 2D6 (CYP2D6) metabolizes many important drugs. CYP2D6 activity ranges from complete deficiency to ultrafast metabolism, depending on at least 16 different known alleles. Their frequencies were determined in 589 unrelated German volunteers and correlated with enzyme activity measured by phenotyping with dextromethorphan or debrisoquine. For genotyping, nested PCR-RFLP tests from a PCR amplificate of the entire CYP2D6 gene were developed. The frequency of the CYP2D6*1 allele coding for extensive metabolizer (EM) phenotype was .364. The alleles coding for slightly (CYP2D6*2) or moderately (*9 and *10) reduced activity (intermediate metabolizer phenotype [IM]) showed frequencies of .324, .018, and .015, respectively. By use of novel PCR tests for discrimination, CYP2D6 gene duplication alleles were found with frequencies of .005 (*1x2), .013 (*2x2), and .001 (*4x2). Frequencies of alleles with complete deficiency (poor metabolizer phenotype [PM]) were .207 (*4), .020 (*3 and *5), .009 (*6), and .001 (*7, *15, and *16). The defective CYP2D6 alleles *8, *11, *12, *13, and *14 were not found. All 41 PMs (7.0%) in this sample were explained by five mutations detected by four PCR-RFLP tests, which may suffice, together with the gene duplication test, for clinical prediction of CYP2D6 capacity. Three novel variants of known CYP2D6 alleles were discovered: *1C (T1957C), *2B (additional C2558T), and *4E (additional C2938T). Analysis of variance showed significant differences in enzymatic activity measured by the dextromethorphan metabolic ratio (MR) between carriers of EM/PM (mean MR = .006) and IM/PM (mean MR = .014) alleles and between carriers of one (mean MR = .009) and two (mean MR = .003) functional alleles. The results of this study provide a solid basis for prediction of CYP2D6 capacity, as required in drug research and routine drug treatment.     

Pilot study for the characterization of pharmacogenetically relevant CYP2D6, CYP2C19 and ABCB1 gene polymorphisms in the Hungarian population

Polymorphisms of CYP450 metabolizer enzymes and transport proteins play crucial roles in the inter‐individual variability of drug efficiency. The aim of our study was to predict the frequency of functional variants of CYP2D6, CYP2C19 and ABCB1 genes in the Hungarian population. One hundred twelve unrelated healthy subjects donated DNA sample in the study. ABCB1 C3435T and G2677T/A single‐nucleotide polymorphisms (SNPs) were determined by LightCycler polymerase chain reaction. Because only limited amount of data is available on the rare allelic variants of CYP2D6 in the European populations, our study applied an expanded set of CYP2D6 and CYP2C19 alleles by using AmpliChip test. Our results show that the CYP2D6 phenotypes were 1.9% ultra‐rapid metabolizer, 6.5% intermediate metabolizer (IM), 8.3% poor metabolizer (PM) and 83.3% extensive metabolizer (EM), and the CYP2C19 phenotypes were 1.8% PM, 31.2% IM and 67% EM. The prevalence of the commonly observed CYP2D6 and CYP2C19 alleles in our study corresponds with that of other European populations. Nevertheless, our study confirms that extending the CYP2D6 allele set with loss‐of‐function variants such as CYP2D6*7, *9, *41 is worth considering. Frequency of the wild type ABCB1 3435C was 42.8% whereas the prevelance of 2677 G was 50.4%. Although frequency data of G2677T/A SNP in the European area are limited, some discrepancies with other studies were found. Copyright © 2011 John Wiley & Sons, Ltd.     

中国汉族个体HLA-A、-B基因全长序列的测定及调控区多态性

文章利用20个中国汉族个体样本建立了稳定精确的HLA-A、-B基因全长序列的克隆测序方法, 获得HLA-A 10个等位基因4.2 kb序列, HLA-B 6个等位基因3.7 kb序列, 序列涵盖了两个基因的所有外显子、所有内含子、5′启动子区以及3′非翻译区(3′UTR)。A*1153是文章发现的一个新等位基因, B*151101的内含子序列、5个HLA-A以及2个HLA-B等位基因的5′启动子序列和3′UTR序列为国际上首次报道, 其他等位基因均延伸了IMGT/HLA数据库中释放的全长序列。文章首次在中国汉族个体中测定了IMGT/HLA数据库中没有覆盖的HLA-A、-B基因的上游5′启动子以及下游3′UTR区域的多态性模式。HLA-A基因5′启动子延伸区域共发现26个SNPs和一处3 bp(AAA/-)的插入/缺失, 3′UTR延伸区域共发现14个SNPs; HLA-B基因5′启动子延伸区域共发现5个SNPs和一处1 bp(T/-)的插入/缺失, 3′UTR延伸区域共发现8个SNPs。通过对两个基因的5′启动子、外显子以及3′UTR的系统发育树分析, 发现两个基因调控区与外显子的进化关系有所不同, HLA-A基因除A*24020101外, 其他等位基因两端调控区与外显子连锁比较紧密, HLA-B基因两端调控区与外显子之间则发生了较为频繁的重组事件。     

Linkage between the CYP2C8 and CYP2C9 genetic polymorphisms

Cytochrome P450 (CYP) 2C8 and 2C9 are polymorphic enzymes. The CYP2C8*3 and CYP2C9*2 are the major variant alleles in Caucasian populations. The enzymes encoded by these variant alleles have impaired function for the metabolism of several drug substrates. In the present study 1468 subjects that were used as population-based controls in the Stockholm Heart Epidemiology Program (SHEEP) were genotyped by allelic discrimination using a 5'-nuclease assay for CYP2C8*1, 2C8*3, 2C9*1, 2C9*2, and 2C9*3 variant alleles in which the frequencies appeared to be 0.91, 0.095, 0.83, 0.11, and 0.066, respectively. Approximately, 96% of the subjects with CYP2C8*3 allele also carried a CYP2C9*2 and 85% of the subjects that had CYP2C9*2 variant also carried a CYP2C8*3. The number of subjects carrying both of the CYP2C8*1*3 and CYP2C9*1*2 was 4.5-fold higher than expected. This strong association may be of importance especially for the metabolism of common substrates of CYP2C8 and CYP2C9 like arachidonic acid that produces physiologically active metabolites.     

Role of CYP2C9 and CYP2C19 polymorphisms in patients with atherosclerosis

The arachidonic acid metabolizing CYP enzymes with prominent roles in vascular regulation are epoxygenases of the two gene family which generate epoxyeicosatrienoic acids. Carriers of CYP2C9 mutant alleles exhibit a diminished CYP2C9 metabolic capacity leading to decreased endothelium-derived hyperpolarizing factors (EDHF) synthesis and an increased risk for atherosclerosis. We investigated whether the polymorphisms of CYP2C9/19 are related with atherosclerosis. We examined 108 patients having angioraphically > or =70 coronary artery narrowing and 90 healthy controls. CYPC2C9/19*2 and CYP2C9/19*3 alleles were investigated in both patients and controls by a real time PCR instrument. There was no significant difference in the distribution of the CYP2C9*2/*3 alleles between cases and the controls. We found that smoker patients having CYP2C9*2 heterozygote genotype have 3.7-fold risk of developing atherosclerosis. CYP2C19*3 heterozygote alleles are more frequent in patients than in controls (10.2%, 5.6% respectively) and it is related with a three-fold risk of atherosclerosis (odds ratio (OR) = 3.75, confidence interval (CI) = 0.75-18.65). It becomes clear that cigarette smoking can cause almost all major diseases prevalent today, such as cancer or heart disease. This inter-subject variability in cigarette-induced pathologies is partly mediated by genetic variants of genes that may participate in detoxification processes, e.g., cytochrome P450 (CYP), cellular susceptibility to toxins, such as p53, or disease development such as atherosclerosis.     

Characterization of CYP1A2, CYP2C19, CYP3A4 and CYP3A5 polymorphisms in South Brazilians

Potential causes of variability in drug response include intrinsic factors such as ethnicity and genetic differences in the expression of enzymes that metabolize drugs, such as those from Cytochrome P450 (CYPs) superfamily. Pharmacogenetic studies search for genetic differences between populations since relevant alleles occur with varying frequencies among different ethnic populations. The Brazilian population is one of the most heterogeneous in the world, resulting from multiethnic admixture of Amerindians, Europeans, and Africans across centuries. Since the knowledge of CYP allele frequency distributions is relevant to pharmacogenetic strategies and these data are scarce in the Brazilian population, this study aimed to describe genotype and allele distributions of 15 single nucleotide polymorphisms (SNPs) at CYP 1A2, 2C19, 3A4, and 3A5 genes in African and European descents from South Brazil. A sample of 179 healthy individuals of European and African ancestry was genotyped by the MassARRAY SNP genotyping system. CYP3A5*3, CYP1A2*1F, CYP3A4*1B, and CYP2C19*2 were the most frequent alleles found in our sample. Significant differences in genotype and allelic distribution between African and European descents were observed for CYP3A4 and CYP3A5 genes. CYP3A4*1B was observed in higher frequency in African descents (0.379) than in European descents (0.098), and European descents showed higher frequency of CYP3A5*3 (0.810) than African descents (0.523). Our results indicate that only a few polymorphisms would have impact in pharmacogenetic testing in South Brazilians. Further studies with larger sample sizes are required also among other Brazilian regions.     

Genetic polymorphisms in cytochrome P4501B1 and susceptibility to head and neck cancer

Cytochrome P4501B1 (CYP1B1), a polycyclic aromatic hydrocarbon (PAH) metabolizing CYP, is genetically polymorphic in humans and may be involved in the individual susceptibility to chemical-induced cancer. In the present study, genotype and haplotype frequencies of four single nucleotide polymorphisms (SNPs) in CYP1B1 that cause amino acid changes (Arg-Gly at codon 48, Ala-Ser at codon 119, Leu-Val at codon 432 and Asn-Ser at codon 453) were studied in 150 cases suffering from head and neck squamous cell carcinoma (HNSCC) and in an equal number of controls. A significant difference was observed for the distribution of variant genotypes of Arg48Gly (CYP1B1*2) and Ala119Ser (CYP1B1*2) polymorphisms of CYP1B1 in cases versus controls. No significant differences were observed for the distribution of variant genotypes-Leu432Val (CYP1B1*3) and Asn453Ser (CYP1B1*4), respectively. When the four SNPs were analyzed using a haplotype approach, SNPs at codon 48 (Arg48Gly) and codon 119 (Ala119Ser) exhibited complete linkage disequilibrium (LD) in all the cases and controls. Significant differences in the distribution of the two haplotypes (G-T-C-A and G-T-G-A) were observed both in the cases and in controls. Furthermore, our data indicates a several fold increase in risk in the cases who use tobacco (cigarette smoking or tobacco chewing) or alcohol with the variant genotypes of CYP1B1 (CYP1B1*2 and CYP1B1*3) suggesting the role of gene-environment interaction in the susceptibility to HNSCC.     

Allele and genotype frequencies of the polymorphic cytochrome P450 genes (CYP1A1, CYP3A4, CYP3A5, CYP2C9 and CYP2C19) in the Jordanian population

Drug metabolizing enzymes participate in the neutralizing of xenobiotics and biotransformation of drugs. Human cytochrome P450, particularly CYP1A1, CYP2C9, CYP2C19, CYP3A4 and CYP3A5, play an important role in drug metabolism. The genes encoding the CYP enzymes are polymorphic, and extensive data have shown that certain alleles confer reduced enzymatic function. The goal of this study was to determine the frequencies of important allelic variants of CYP1A1, CYP2C9, CYP2C19, CYP3A4 and CYP3A5 in the Jordanian population and compare them with the frequency in other ethnic groups. Genotyping of CYP1A1(m1 and m2), CYP2C9 (*2 and *3), CYP2C19 (*2 and *3), CYP3A4*5, CYP3A5 (*3 and *6), was carried out on Jordanian subjects. Different variants allele were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). CYP1A1 allele frequencies in 290 subjects were 0.764 for CYP1A1*1, 0.165 for CYP1A1*2A and 0.071 for CYP1A1*2C. CYP2C9 allele frequencies in 263 subjects were 0.797 for CYP2C9*1, 0.135 for CYP2C9*2 and 0.068 for CYP2C9*3. For CYP2C19, the frequencies of the wild type (CYP2C19*1) and the nonfunctional (*2 and *3) alleles were 0.877, 0.123 and 0, respectively. Five subjects (3.16?%) were homozygous for *2/*2. Regarding CYP3A4*1B, only 12 subjects out of 173 subjects (6.9?%) were heterozygote with none were mutant for this polymorphism. With respect to CYP3A5, 229 were analyzed, frequencies of CYP3A5*1,*3 and *6 were 0.071, 0.925 and 0.0022, respectively. Comparing our data with that obtained in several Caucasian, African-American and Asian populations, Jordanians are most similar to Caucasians with regard to allelic frequencies of the tested variants of CYP1A1, CYP2C9, CYP2C19, CYP3A4 and CYP3A5.     

Genetic risk assessment towards warfarin application: Saudi Arabia study with a potential to predict and prevent side effects

Warfarin doses are greatly affected by polymorphism altering cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) gene. This study evaluated the prevalence of alleles (either single or double) and carriers of single nucleotide polymorphisms (SNPs) in both genotypes CYP2C9 and VKORC1 in alkharj area, Saudi Arabia and its association with warfarin use risk. Total 112 samples were collected and genotyped using FlexiGene DNA Kit for isolation and StepOnePlus Real-Time PCR System by TaqMan allelic discrimination methods. The results indicated the frequency of 11%, 8% and 45% for CYP2C9 *2 *3 and VKORC1-1639 G > A polymorphism. And as a combination genotype it was 15.18% For both CYP2C9 and VKORC1 polymorphism, 27.67% for CYP2C9 and 42.86% for VKORC1. Non-carriers rate came to be at 30.3%. According to previously published dosing changes in warfarin for polymorphism carriers (single-double-triple). The predicted warfarin doses reduction in order of 1–1.6, 2–2.9, 2.9–3.7 mg/day. It was found that 72.3% of the study population was carrier of a type of polymorphism, 15.18% for two types of polymorphisms. These findings predict changes in warfarin metabolism and eventually dosing alteration among patients on warfarin. Both genotypes (CYP2C9 and VKORC1) require different dosing of warfarin than non-carriers in order to minimize the risk of warfarin overdosing and avoidance of the drug-related problems (DRPs).     

Comparison between MassARRAY and pyrosequencing for CYP2C19 and ABCB1 gene variants of clopidogrel efficiency genotyping

Clopidogrel is one of the most frequently used drugs in patients to reduce cardiovascular events. Since patients with different genetic variations respond quite differently to clopidogrel therapy, the related genetic testing plays a vital role in its dosage and genetic testing related to clopidogrel therapy is currently considered as routine test worldwide. In this study, we aim to use two different methods MALDI-TOF mass spectrometry and pyrosequencing to detect gene variant of CYP2C19 and ABCB1. Six single nucleotides polymorphisms (SNP) within CYP2C19 (*2, *3, *4, *5, *17) and ABCB1 C3435T in 458 Chinese Han patients were determined using both MassARRAY and Pyrosequencing. Sanger sequencing was used for verification. Results of both methods were analyzed and compared. Allele frequencies of each SNP and distribution of different genotypes were calculated based on the MassARRAY and Sanger sequencing results. Both methods provided 100% call rates for gene variants, while results of six samples were different with two methods. With Sanger sequencing as the reference results, MassARRAY generated all the same results. The minor allele frequencies of the above six SNPs were 27.1% (CYP2C19*), 5.9% (CYP2C19*3), 0% (CYP2C19*4), 0% (CYP2C19*5), 1.1% (CYP2C19*17), 40.9% (ABCB1), respectively. MassARRAY provides accurate clopidogrel related genotyping with relatively high cost-efficiency, throughput and short time when compared with pyrosequencing.     

Influence of CYP3A4, CYP3A5 and MDR-1 polymorphisms on tacrolimus pharmacokinetics and early renal dysfunction in liver transplant recipients

Objectives

Tacrolimus is a widely used immunosuppressive drug in organ transplantation. The oral bioavailability of tacrolimus varies greatly between individuals and depends largely on the activity of both the cytochrome P450 3A (CYP3A) subfamily and P-glycoprotein (P-gp). The possible influence of single nucleotide polymorphisms (SNPs) of CYP3A subfamily and P-gp (MDR-1) in liver transplant recipients has recently been indicated as one of the most important variables affecting the pharmacokinetics of tacrolimus and the renal injury induced by tacrolimus.

Methods

A total of 216 liver transplant recipients were enrolled in this study. The recipients' mean follow-up time was 52 mo (range from 16 to 96 mo). All liver transplant recipients were all in a stable stage with normal serum creatinine (SCr). All liver transplant recipients treated with tacrolimus were genotyped for CYP3A5 (6986A>G), CYP3A4 intron 6 (CYP3A4*22), MDR-1 exon 26 (3435C>T) and exon 12 (1236 C>T) SNPs by HRM analysis (high-resolution melting curve analysis). Recipients were defined as the early renal injury by the elevation of different microproteins in the urine including microalbumin (MA), urine immunoglobulin G (IGU), urine transferrin (TRU) and α1-microglobulin (A1M).

Results

The daily dose of tacrolimus was higher for recipients with CYP3A5*1/*1 (AA) genotype than those with CYP3A5*3/*3 (GG) genotype [3.0 (2.0–4.0) versus 2.0 (1.5–2.5) mg/d, P < 0.05]. The concentration/dose ratio of recipients with CYP3A5*1 homozygotes was lowest compared to recipients with CYP3A5*3/*3 and CYP3A5*1/*3 genotypes. Furthermore, the recipients carrying CYP3A5*3 allele were associated with increased risk of early renal glomerular injury compared to the recipients carrying CYP3A5*1 allele (P = 0.01). MDR-1 polymorphisms were not related with tacrolimus pharmacokinetics and early renal injury.

Conclusion

CYP3A5 6986A>G genetic polymorphism affected daily dose requirements, concentration and nephrotoxicity of tacrolimus. Screening for this single nucleotide polymorphism before the transplantation might be helpful for the selection of adequate initial daily dose and to achieve the desired immunosuppression outcome.     

Allele and genotype frequencies of CYP2B6 in a Turkish population

Increasing interest in cytochrome P450 2B6 (CYP2B6) genetic polymorphism was stimulated by revelations of a specific CYP2B6 genotype significantly affecting the metabolism of various drugs in common clinical use in terms of increasing drug efficacy and avoiding adverse drug reactions. The present study aimed to determine the frequencies of CYP2B6*4 CYP2B6*5, CYP2B6*6, CYP2B6*7 and CYP2B6*9 alleles in healthy Turkish individuals (n = 172). Frequencies of three single nucleotide polymorphisms were 516G>T (28 %), 785A>G (33 %), and 1459C>T (12 %). The frequencies of CYP2B6*1, *4, *5, *6, *7, and *9 alleles were 54.3 (95 % CI 49.04–59.56), 6.4 % (95 % CI 3.81–8.99), 11 % (95 % CI 7.69–14.31), 25.3 % (95 % CI 20.71–29.89), 0.87 % (95 % CI ?0.11–1.85) and 2.0 % (95 % CI 0.52–3.48), respectively. Allele *6 was more frequent (25.3 %) than the other variant alleles in Turkish subjects. The frequencies of CYP2B6*4, *5, *6, *7, and *9 alleles were similar to European populations but significantly different from that reported for Asian populations. This is the first study to document the frequencies of the CYP2B6*4, *5, *6, *7, *9 alleles in the healthy Turkish individuals and our results could provide clinically useful information on drug metabolism by CYP2B6 in Turkish population.     

Screening of 12 SNPs of CYP3A4 in a Chinese population using oligonucleotide microarray

Human cytochrome P450 3A4 (CYP34A) plays an important role in the metabolism of many endo- and xenomaterials. It also exhibits a substantial interindividual variation in enzymatic activity. It has been shown that the mutant alleles of CYP3A4 encoding inactive/decreased enzymes are largely caused by single nucleotide polymorphisms (SNPs) in the gene sequence. In the present study, with the goal of detecting the known SNPs of CYP3A4, an oligonucleotide microarray was created. A genotyping standard for this microarray was also established using constructed plasmids as standard templates. The 12 SNPs of CYP3A4 in 387 Chinese DNA samples were screened using this oligonucleotide microarray. Three heterozygous subjects of CYP3A4*/*4, 5 heterozygous subjects of CYP3A4*1/*5, 4 heterozygous subjects of CPY3A4*1/6, and 6 heterozygous subjects of CYP3A4*1/*18 were found. The genotyping results of the 18 heterozygous subjects and 12 wild-type subjects were validated by direct sequencing.     

CYP2C9 genotype and association with bone mineral density: A pilot study

Background

In recent years reduced bone mineral density (BMD) and osteoporosis have become major public health problems. Single nucleotide polymorphisms (SNPs) in the cytochrome P450 2C9 (CYP2C9) gene influence the response to oral anticoagulant drugs, which are positively associated with the risk to develop osteoporosis. The aim of the present investigation was to clarify a potential role of CYP2C9 sequence variations and susceptibility to develop osteoporosis.

Subjects and methods

Ninety two consecutive angiologic outpatients, mean age: 60.3 ± 14.4, without secondary causes of bone loss were genotyped and classified as patients with normal BMD, osteopenia and osteoporosis according to WHO criteria by dual-energy X-ray absorptiometry at the lumbar spine and/or the femoral neck. Potential association between the CYP2C9 genotype and BMD was tested.

Results

59% of the patients (n = 54) presented with reduced BMD and were compared to 38 age-matched persons with normal BMD. The genotype distribution showed 15% heterozygous for CYP2C9*2 p.Arg144Cys, 14% for CYP2C9*3 p.IIe359Leu, 2% for both polymorphisms, and 69% had wildtype genotypes. Patients with CYP2C9 mutations had significantly lower BMD values at the femoral neck and displayed a four-fold higher adjusted risk to suffer from reduced BMD than individuals with wildtype genotypes (p = 0.02).

Discussion

Oral anticoagulant treatment is common in angiologic outpatients. The gene variants CYP2C9*2 and CYP2C9*3 have been shown to require lower maintenance doses of oral anticoagulant drugs. An association between oral anticoagulant drugs and the susceptibility to develop osteoporosis in relation to sequence variations in the CYP2C9 gene is suggested to be mediated via the glucocorticoid synthesis pathway.

Conclusion

The CYP2C9*2/CYP2C9*3 variants were significantly associated with femoral BMD in a selected elderly Austrian population. These variants could contribute to the complex risk to develop osteoporosis.