药物代谢酶CYP3A和多药耐药基因在中国肾移植人群的遗传多态性

目的 建立基质辅助激光解吸电离飞行时间质谱技术(MASS ARRAY)测定中国肾移植人群的CYP3A5*3、CYP3AP1和多药耐药基因(MDR1)的多态性.方法 用MASS ARRAY技术对60例中国肾移植人群的CYP3AS*3、CY3AP1和MDR1位点进行基因分型.结果 CYP3A5*I等位基因占25.9%,*3等位基因占74.1%,CYP3AP1 A等位基因占26.7%,G等位基因占73.3%,MDR1 C1236T、G2677T/A、C3435T个体突变频率分别为65.6%、38.3%、36.6%.结论 中国肾移植人群中CYP3A5*3、CYP3AP1和MDR1位点存在遗传多态性,影响不同个体药物代谢酶活性和药物代谢.     

细胞色素P450 3A5和多药耐药基因遗传变异的联合效应对克拉霉素药代动力学的影响

目的 观察CYP3A5*3和MDR1 C3435T遗传变异的联合效应对中国健康受试者克拉霉素(大环内酯类抗生素)药代动力学的影响.方法 45名受试者服用单剂量克拉霉素胶囊250 mg,HPLC-MS法测定血药浓度.PCR-ASA法和PCR-RFLP法分别测定受试者CYP3A53和MDR1 C3435T的基因型,按基因型分组,比较基因多态性对克拉霉素药代动力学的影响.结果 在45名受试者中,CYP3A5*3各基因型分布,不受MDR1 C3435T基因型的影响;而2者的基因突变均不同程度地协同影响克拉霉素药代动力学参数Cmax、AUC0-24和tmax.结论 CYP3A5*3和MDR1 C3435T遗传变异及协同作用是影响克拉霉素药代动力学特性的重要因素.     

细胞色素 P4503 A4与 P4503 A5及多药耐药基因多态性对氨氯地平降压疗效影响研究

目的：探讨细胞色素 P450（ CYP）3A4倡1G、CYP3A5倡3及多药耐药（MDR1） C1236T、MDR1 G2677T／A和MDR1 C3435T基因多态性对氨氯地平降压疗效的影响。方法纳入159名原发性高血压患者,予氨氯地平5 mg· d－1干预4周,检测相关基因型,分析不同个体CYP3A4、3A5及MDR1相关基因型分布特征,考察不同单核苷酸多态性（ SNP）及MDR1单倍体对氨氯地平降压疗效的影响。结果 CYP3A4倡1G倡1G 基因型舒张压（ DBP）下降幅度显著低于CYP3A4倡1G倡1和CYP3A4倡1倡1（P＜0.05）;CYP3A5倡3倡3基因型DBP下降幅度显著高于CYP3A5倡1倡3和CYP3A5倡1倡1（P＜0.05）;MDR1 C1236T CC、MDR1 G2677T／A AA基因型收缩压（SBP）下降幅度显著高于其他基因型（P＜0.05）;MDR1 C3435T各基因型治疗前后SBP、DBP下降幅度差异均无统计学意义（P＞0.05）。携带MDR1 C3435T CC、MDR1 C3435T CT基因型的患者的DBP下降幅度,女性显著高于男性（ P＜0.05）。对MDR1单倍体分析,各组单倍体治疗前后 SBP、DBP 下降幅度差异均无统计学意义（ P ＞0.05）。结论CYP3A5倡3、CYP3A4倡1G基因多态性可影响氨氯地平降压疗效,MDR1各单倍体未发现与氨氯地平降压疗效相关。     

CYP3A4/5、ABCB1基因单倍型与中国肾移植患者他克莫司血药谷浓度相关性的研究

目的:探讨CYP3A4*18B、CYP3A5*3、ABCB1基因单倍型对中国肾移植患者术后一月内他克莫司谷浓度(C0/D)的影响。方法:采用限制性片段长度多态性技术分析46名肾移植患者CYP3A4*18B、CYP3A5*3、ABCB1(外显子C1236T、G2677A/T、C3435T)基因型,采用酶增强免疫测定技术测定患者C0值。结果:经分析患者CYP3A4*18B、CYP3A5*3、ABCB1(C1236T,G2677A/T,C3435T)等位基因频率分别为0.304、0.707、0.554、0.478和0.304,均符合HardyWeinberg平衡。CYP3A4-3A5、G2677A/T-C3435T及C1236T-C3435T间均表现为连锁不平衡。术后8~15、16~30天内CYP3A4*18B与患者FK506 C0/D值显著相关,野生型患者C0/D值分别为杂合及突变型患者的1.34和1.67倍。CYP3A5*3基因也与患者FK506 C0/D值显著相关。突变型患者C0/D值在术后1~7、8~15及16~30天时分别为野生及杂合型患者的1.56、1.98及1.99倍。单倍型分析发现CYP3A4/5单倍型GG型携带者C0/D值较非携带者在移植术后8~15、16~30天显著性增加1.43、1.77倍。未观察到ABCB1基因多态性及单倍型对FK506血药浓度的影响。结论:仅CYP3A4/5单倍型与他克莫司C0/D值显著相关,移植前对CYP3A4/5单倍型进行检测将有利于他克莫司给药剂量的调整。     

111例心衰患者的 MDR1 和CYP3A 基因多态性与地高辛血药浓度的相关性研究

目的：观察中国贵州地区汉族心衰患者中MDR1C3435T、CYP3A4＊18B和CYP3A5＊3等位基因多态性对地高辛血药浓度的影响。方法：收集111名中国贵州地区汉族心衰患者的血样与地高辛治疗药物浓度监测（TDM）数据,通过PCR-RFLP法分析患者的MDR1C3435T、CYP3A4＊18B及CYP3A5＊3基因型,分析每个基因的多态性对地高辛血药浓度的影响。结果：70岁以上患者MDR1各基因型组中,野生纯合子（CC）组、突变杂合子（CT）组、突变纯合子（TT）组的地高辛血药浓度依次增高。CC组和CT组较TT组的地高辛血药浓度差异有统计学意义（P〈0.05）;CYP3A4和CYP3A5各基因型组之间的地高辛血药浓度差异均无统计学意义（P〉0.05）。结论：MDR1C3435T等位基因突变可使地高辛血药浓度提高;而CYP3A4＊18B和CYP3A5＊3等位基因突变对地高辛的血药浓度无明显影响。     

CYP3A5和MDR1基因多态性对中国肝移植患者他克莫司药动学的影响

目的探讨细胞色素P450酶3A5（CYP3A5）基因和多药耐药基因（MDR1）C1236T、G2677T／A、C3435T多态性对肝移植患者口服他克莫司（TAC）后体内药动学参数的影响。方法采集28例肝移植患者手术后第1周和第3周血标本,采用LC—MS／MS法检测TAC血药浓度,计算主要药动学参数。采用聚合酶链反应结合基因测序分析28例肝移植患者CYP3A5＊3和MDR1主要基因型。结果携带MDR1 3435T基因型的肝移植患者口服TAC后,药动学参数AUC0→1和ρmax明显高于3435CC型患者,而CYP3A5＊3、MDR1 C1236T和G2677T／A基因多态性对TAC的药动学参数无明显影响。结论携带MDR1 3435T基因型肝移植患者比3435CC型患者需要较高剂量才能达到目标浓度。     

MDR1基因多态性和单倍体对肾移植术后稳定期患者他克莫司浓度/剂量比值的影响

目的 探讨MDR1 C1236T、G2677T/A和C3435T 基因多态性和单倍体对中国汉族肾移植术后稳定期患者他克莫司浓度/剂量比值的影响,为他克莫司个体化用药提供依据。方法 采用PCR-基因测序法检测104例肾移植术后稳定期患者MDR1 C1236T、G2677T/A和C3435T 的基因多态性,采用均相酶免疫测定方法(EMIT法)测定他克莫司的谷浓度,比较不同基因型患者之间他克莫司血药浓度/(剂量×体质量)(C/D)比值。结果 104例患者中,MDR1 C1236T、G2677T/A和C3435T突变频率分别为56.73%、55.77%和33.17%。MDR1 C3435T、MDR1 TTT单倍体与他克莫司C/D比值具有相关性(P<0.05)。CYP3A5*3*3患者中,MDR1 TTT单倍体与他克莫司C/D比值仍存在显著相关(P<0.05)。MDR1 C1236T、G2677T/A、CGC单倍体与他克莫司C/D比值无显著性差异(P>0.05)。结论 MDR1 C3435T、MDR1 TTT单倍体与中国汉族肾移植术后稳定期患者他克莫司C/D比值具有显著相关性,是影响肾移植患者他克莫司浓度个体化差异的重要因素。     

CYP3A5和ABCB1基因多态性对肾移植患者术后初期他克莫司剂量、浓度及肾功能的影响

目的研究CYP3A5和ABCB1基因多态性对肾移植患者术后初期他克莫司剂量、浓度以及肾功能的影响。方法以200例肾移植患者为研究对象,使用聚合酶链式反应(PCR)-限制性内切片段长度多态性(RFLP)法和测序法检测患者CYP3A5*3和ABCB1(C1236T、G2677T/A、C3435T)基因型,比较肾移植术后28 d内不同基因型患者之间他克莫司血药浓度(C)、剂量(D)、浓度剂量比(C/D)以及肾功能(血清肌酐和胱抑素C水平)的差异。结果 CYP3A5非表达组(CYP3A5*3*3型)的C和C/D在术后7、14、21和28 d均显著高于CYP3A5表达组(CYP3A5*1*1和CYP3A5*1*3型)(P <0.05,P<0.01)。ABCB1 1236基因多态性对CYP3A5表达组患者的他克莫司C、D及C/D均没有显著影响;对于CYP3A5非表达组,ABCB1 1236 CT和TT型患者他克莫司的D及C/D有显著性差异。对于CYP3A5表达组,ABCB1 3435 TT型患者他克莫司的C和D显著低于CC型和CT型患者(P <0.05);而在CYP3A5非表达组中,ABCB1 3435 TT型患者的他克莫司D显著低于CT型。对肾功能的影响:ABCB11236和2677基因型对CYP3A5表达组和非表达组肾功能均没有显著影响。对于CYP3A5非表达组,ABCB1 3435 TT型患者移植后第7或14日肌酐和胱抑素C水平显著高于CC和CT型患者(P <0.05)。结论肾移植术后初期,CYP3A5*3、ABCB1 C1236T和ABCB1 C3435T基因多态性影响他克莫司C和D,ABCB1 C3435T基因多态性对肾功能有影响。     

有机阴离子转运因子2的多态性与某省新生儿重症高胆红素血症的相关性研究

目的探讨有机阴离子转运因子2(OATP2)的A388G及T521C基因多态性与云南省新生儿高胆红素血症的相关性。方法 180例新生儿重症高胆红素血症作为病例组,80例无黄疸新生儿作为对照组。采用常规方法提取DNA,用聚合酶链反应(PCR)方法扩增,琼脂糖凝胶电泳鉴定产物,PCR产物进行DNA测序。结果病例组与对照组A388G等位基因突变率分别为25%及23%,病例组A388G基因频率与对照组间差异无统计学意义(χ2=1.056,P>0.05);病例组与对照组T521C基因等位基因突变率分别为9%及3%,病例组T521C基因频率显著高于对照组,差异有统计学意义(χ2=5.590,P<0.05)。结论云南省重症新生儿高胆红素血症的发生与有机阴离子转运因子2的A388G基因突变无关,而与T521C基因的多态性密切相关。     

焦磷酸测序技术检测SLCO1B1基因多态性方法的建立

目的:建立SLCO1B1A388G和T521C单核苷酸多态位点的焦磷酸测序方法,分析中国健康人群中分布频率。方法:制备300例健康人外周血gDNA,应用PyroMark ID焦磷酸测序仪进行多态位点分型分析。并通过重复性检验和毛细管电泳测序验证方法正确性。结果:建立了SL-CO1B1A388G和T521C多态性分析的焦磷酸测序新方法,经毛细管电泳测序验证和重复性验证,结果准确可靠。在300例标本中,388A、388G、521T、521C等位基因频率分别为28%、72%、89.5%和10.5%,符合Hardy-Weinberg平衡。结论:焦磷酸测序方法可准确、高通量、快速检测SLCO1B1A388G和T521C单核苷酸多态性,特别适宜大样本量的临床及科研批量检测需要。     

Pharmacokinetics of paclitaxel in ovarian cancer patients and genetic polymorphisms of CYP2C8, CYP3A4, and MDR1

Interindividual differences in the pharmacokinetics of paclitaxel and its metabolites in Japanese ovarian cancer patients were investigated in relation to genetic polymorphisms of the CYP2C8, CYP3A4, and MDR1 genes. The area under the concentration-time curve (AUC) ratios of paclitaxel/6alpha-hydroxypaclitaxel and paclitaxel/3 -p-hydroxypaclitaxel calculated as the metabolic index of CYP2C8 and CYP3A4 showed 13- and 12-fold interindividual variations, respectively. No patient had any CYP2C8 variants, while 2 patients were heterozygotes of CYP3A4*16. For the MDR1 gene, the frequencies of -129C, 1236C, 2677T, 2677A, and 3435T alleles were 2.2%, 8.7%, 56.5%, 4.4%, and 52.2%, respectively. Subjects possessing the 3435T allele had a significantly (P < .05) higher AUC of 3'- p-hydroxypaclitaxel compared to those possessing the 3435C allele. Leukocytopenia was significantly (P < .05) related to the AUC of paclitaxel. Genotyping of the CYP2C8, CYP3A4, and MDR1 genes might not be essential to predict adverse effects of paclitaxel in Japanese patients, although an allelic variant of MDR1 may functionally affect the pharmacokinetics of its metabolite.     

Frequencies and roles of CYP3A5, CYP3A4 and ABCB1 single nucleotide polymorphisms in Italian teenagers after kidney transplantation

The main genes involved in the pharmacokinetics of immunosuppressive drugs are those encoding cytochrome P450 (CYP) family enzymes and multidrug resistance 1 (ABCB1). In this study, 87 Italian teenagers with transplanted kidneys (mean age 11.6 ± 4.8 years) receiving calcineurin inhibitors (CNIs) were genotyped for the single nucleotide polymorphisms (SNPs) CYP3A5*1/3 and CYP3A4*1B for CYP3A, and C1236T, G2677T/A, C3435T and IVS21+49 for ABCB1, and retrospectively evaluated for the influence of the screened SNPs on CNI blood level at different post-transplantation times. The CYP3A5*1 allele was present in 7% of the patients, and the CYP3A4*1B allele was present in 3% of patients. The ABCB1 C1236T, G2677T/A and C3435T SNPs C, G and T occurred frequently (55%, 53% and 54%, respectively). The frequency of the T allele of IVS21+49 was 86%. The frequency of SNPs in both genes was comparable with that reported in other European Caucasian populations but different from that found in Asians or Afro-Americans. None of the cyclosporine (CsA) pharmacokinetic parameters were associated with the CYP3A5 genetic polymorphism, whereas the presence of the A allele in some patients was responsible for the required administration of a significantly increased dose of tacrolimus (Tac) that was necessary to reach therapeutic target levels. None of the Tac pharmacokinetic parameters were associated with ABCB1 SNPs, but ABCB1 SNPs had early effects on the CsA exposure index and dose requirements. In conclusion, because SNPs of the CYP3A and ABCB1 genes may be associated with CNI pharmacokinetic parameters and exposure indices, pre-transplant genetic screening should be considered in order to avoid immunosuppressant-related adverse events.     

The effect of CYP3A5 and MDR1 polymorphic expression on cyclosporine oral disposition in renal transplant patients

Variability in CYP3A (CYP3A4/5) and P-glycoprotein (human MDR1 gene product) activity underlies interindividual differences in oral cyclosporine (CsA) bioavailability. Racial differences in polymorphic expression of CYP3A5 and MDR1 may explain observed interracial variability in oral bioavailability. Our objective was to evaluate the effect of CYP3A5 and MDR1 polymorphic expression on CsA oral disposition. Steady-state plasma concentration profiles (n = 19) were sampled in renal transplant recipients receiving concentration-adjusted CsA maintenance therapy. CsA plasma concentrations were measured by fluorescence polarization immunoassay. CYP3A5 and MDR1 genotypes were determined by real-time polymerase chain reaction. Noncompartmental pharmacokinetic analysis and nonlinear mixed-effects modeling (NONMEM) were performed to assess the effect of genotype on CsA pharmacokinetics. MDR1 C3435T genotype was identified as the best predictor of CsA systemic exposure. CsA oral clearance was significantly higher in subjects who carried at least one 3435T allele compared to homozygous wild-type individuals (40.0 +/- 2.2 vs. 26.4 +/- 3.1 L/h, p = 0.007). MDR1 C3435T genotype accounted for 43% of the interindividual variability of CsA oral clearance in the study population after accounting for interoccasion variability. The authors were unable to independently assess whether CYP3A5 correlated with any CsA pharmacokinetic parameter since all CYP3A5 nonexpressors were also 3435T allele carriers. MDR1 3435T allele carriers have enhanced oral clearance compared to individuals with the CC genotype. The frequency of the 3435T allele is lower in African Americans compared to Caucasians. Thus, the MDR1 C3435T genotype offers a potential mechanistic basis to explain interracial differences in CsA oral bioavailability. Further studies are needed to explore the relationship between CYP3A5 and MDR1 genotype and phenotype.     

CYP3A5*3 and MDR-1 C3435T single nucleotide polymorphisms in six Chinese ethnic groups

The prevalent CYP3A5 *3 and the functional multi-drug resistance gene (MDR1) C3435T show marked interethnic variation among Orientals, Caucasians and Africans. This study aimed to investigate the distribution of CYP3A5*3 and MDR1 C3435T among Chinese ethnic groups. Genotypes of the CYP3A5*3 and MDR1 C3435T were determined in 839 unrelated healthy Chinese subjects by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assays. Frequencies (P < 0.05) of CYP3A5*3 variant alleles observed in Uygur Chinese, Kazakh Chinese and Tibetan Chinese (88.1%, 84.5% and 80.7%, respectively) were Significantly higher than those in Han Chinese, Wa Chinese and Bai Chinese (67.3%, 56.3% and 70.2%, respectively). Significantly higher 3435T variant frequencies (P < 0.05) were observed in Uygur Chinese (58.4%) and Kazakh Chinese (56.8%) compared with Han Chinese (44.2%), Tibetan Chinese (43.9%), Wa Chinese (45.8%) and Bai Chinese (44.2%). These results indicate that there were marked ethnic differences in the mutant frequencies of CYP3A5*3 and MDR1 C3435T among Chinese ethnic groups. Frequencies of those variants observed in Uygur Chinese, Kazakh Chinese, Tibetan Chinese, Wa Chinese and Bai Chinese wereintermediate between those seen in Han Chinese and African-American.     

Differences in CYP3A5*3 genotype distribution and combinations with other polymorphisms between Spaniards and Other Caucasian populations

The goal of this study was to detect genotypic differences between Spaniards and other related populations regarding CYP3A4*1B, CYP3A5*3, and ABCB1 (MDR1) C3435T polymorphisms. DNA from 177 Spanish patients were analyzed for the presence of these mutations using PCR-restriction fragment length polymorphism or direct sequencing. The observed frequencies for CYP3A4*1B, CYP3A5*3, and C3435T alleles were within normal values in Caucasians (0.04, 0.91, and 0.5, respectively). However, 2.8% of the patients were homozygous for the wild-type CYP3A5*1 allele, an extremely uncommon genotype in other Caucasians. In addition, analysis of CYP3A4-3A5 haplotypes revealed the existence of 2 unusual subgroups: patients who were homozygous wild-type for both polymorphisms, and patients showing a CYP3A4*1A/*1B-CYP3A5*3/*3 genotype combination. The incidence of CYP3A5*1/*1 carriers and the occurrence of subjects combining the 2 above-mentioned unusual genotype combinations were more frequent in Spanish-Caucasians compared with American- or European-Caucasians. ABCB1 C3435T genotype frequencies were equally distributed between both single and combined CYP3A4 and 3A5 genotypes. These findings suggest that dose requirements for drugs metabolized by CYP3A and certain allele-disease association studies in white populations could show discrepancies in Spaniards.     

Effects of genetic polymorphisms of CYP3A4, CYP3A5 and MDR1 on cyclosporine pharmacokinetics after renal transplantation

1. The calcineurin inhibitor cyclosporine is widely used to prevent allograft rejection after solid organ transplantation. It has a narrow therapeutic index and shows considerable interindividual differences in its pharmacokinetics. Interindividual differences in the activity and expression of the metabolising enzymes cytochrome P450 (CYP) 3A4 and 3A5 and the multidrug efflux pump P-glycoprotein (P-gp) contribute considerably to cyclosporine pharmacokinetics. Variability in the activity of CYP3A4, CYP3A5 and P-gp could be considered to result from genetic polymorphisms encoding their genes. 2. The aim of the present study was to evaluate retrospectively the effects of genetic polymorphisms of CYP3A4, CYP3A5 and MDR1 on cyclosporine dose adjusted trough blood concentration during the early period after renal transplantation in Chinese patients. 3. One hundred and six renal transplant recipients in China were genotyped by polymerase chain reaction-restriction fragment length polymorphism for CYP3A4*18A, CYP3A5*3 and MDR1 C3435T. Cyclosporine whole blood levels were measured by fluorescence polarization immunoassay. Dose-adjusted trough blood concentrations (C(0)) were determined and compared among the different genotype groups. 4. The frequency of the CYP3A4*18A, CYP3A5*3 and MDR1 C3435T variant alleles were 0.005 (95% confidence interval (CI) 0.048, 0.0049), 0.783 (95% CI 0.781, 0.785) and 0.528 (95% CI 0.526, 0.531), respectively, and these alleles exhibited incomplete linkage disequilibrium. The median cyclosporine dose-adjusted C(0) in CYP3A5*1/*1 genotype subjects (n = 6) was 14.8 ng/mL per mg per kg (range 11.1-26.8 ng/mL per mg per kg), in CYP3A5*1/*3 patients (n = 34) it was 23.7 ng/mL per mg per kg (range 9.0-61.0 ng/mL per mg per kg) and for CYP3A5*3/*3 patients (n = 66) it was 26.4 ng/mL per mg per kg (range 9.8-85.8 ng/mL per mg per kg; P = 0.012, Kruskal-Wallis test). Accordingly, cyclosporine dose-adjusted C0 was larger in CYP3A5 non-expressors than expressors in the first week after renal transplantation. In addition, wild-type homozygotes (n = 21) for MDR1 C3435T had a slight but significantly lower dose-adjusted C0 compared with heterozygotes (n = 58): 17.7 (10.3-60.8) versus 26.4 (9.0-67.3) ng/mL per mg per kg, respectively (P = 0.014, Mann-Whitney U-test). 5. In conclusion, the present study shows that genetic polymorphisms in CYP3A5 may be responsible, in part, for the large interindividual variability of cyclosporine pharmacokinetics during the early phase after renal transplantation in Chinese patients. Patients with the CYP3A5*3 variant genotype require a low dose of cyclosporine to reach target levels compared with those with the CYP3A5*1 allele.     

MDR1 haplotypes derived from exons 21 and 26 do not affect the steady-state pharmacokinetics of tacrolimus in renal transplant patients

AIM: This retrospective study investigated the influence of MDR1 haplotypes derived from the polymorphisms 2677G > T (exon 21) and 3435C > T (exon 26) on the pharmacokinetics of the immunosuppressant drug tacrolimus in 73 renal transplant patients. METHODS: Based on both variants of SNPs 2677 and 3435, four different haplotypes and eight different genotypes were identified in the study sample. Tacrolimus trough concentrations (C(0)) were compared between different SNP variants and genotypes, as well as between carriers and noncarriers of each haplotype. Additionally, CYP3A5 genotype (6956G > A) was determined. RESULTS: No significant differences were observed between groups. Differences in mean tacrolimus C(0) values between carriers and noncarriers of each haplotype ranged from -0.04 microg/litre (95% confidence interval: -0.53 to 0.60) to -23 microg/litre (-1.07 to 1.53). No association was found between CYP3A5*1/*3 genotype and tacrolimus Co concentractions. CONCLUSION: MDR1 haplotypes derived from the SNPs 2677G > T (exon 21) and 3435C > T (exon 26) do not influence the pharmacokinetics of tacrolimus in renal transplant patients.     

CYP3A5 Genotype is Associated with Diagnosis of Hypertension in Elderly Patients

OBJECTIVE: The aim of this study was to address the presently controversial question of whether cytochrome P450 (CYP) 3A5 polymorphism is associated with hypertension. METHOD: We studied 373 elderly (age > or =75 years) Finnish (Caucasian) patients from the ongoing DEBATE (Drugs and Evidence Based Medicine in the Elderly) trial. The patients were classified into those with a history of hypertension (n = 229) and those without a history of hypertension (n = 144) on the basis of a detailed questionnaire on each patient's medical history and an interview. The patients were genotyped for the CYP3A5 6986A/G single nucleotide polymorphism (SNP) [CYP3A5*1/*3 alleles]. RESULTS: The proportion of individuals with the CYP3A5*1/*3 genotype, i.e. CYP3A5 expressors, was significantly higher among patients with a diagnosis of hypertension than among patients without (18.3% vs 9.0%, p = 0.016). The corresponding odds ratio was 2.26 (95% CI 1.17, 4.38). The allele and genotype frequencies for the two control SNPs, ABCB1 (MDR1) 3435C/T and SLCO1B1 521T/C, did not differ between the two groups. CONCLUSION: This work lends support to the theory that the polymorphic CYP3A5 enzyme may be involved in regulation of blood pressure. The possible role of CYP3A5 as a genetic contributor to hypertension susceptibility warrants further study.