Is thiopurine methyltransferase genetic polymorphism a major factor for withdrawal of azathioprine in rheumatoid arthritis patients?

OBJECTIVE: To determine whether the presence of thiopurine methyltransferase (TPMT) alleles associated with reduced or absent activity of thiopurine methyltransferase is a major factor for withdrawal of azathioprine (AZA) in rheumatoid arthritis (RA) patients. METHODS: The TPMT genotype, including the variable number of tandem repeats (VNTR) pattern in the 5' untranslated region, was analysed in 111 patients with long-standing RA. Azathioprine (AZA) therapy was used in 40 patients (36%) as a disease-modifying anti-rheumatic drug. RESULTS: Seven out of 111 RA patients (6.3%) were carriers of a mutant allele, TPMT3A (G(460)-->A, A(719)-->G) being the mutant allele observed most frequently. In the group of 40 AZA-treated patients, therapy was discontinued in six patients because of side-effects and in 26 patients because of lack of efficacy. Three patients presented moderate side-effects and were homozygous for the wild-type TPMT allele, whereas the remaining three patients, who developed gastrointestinal effects with severe nausea and vomiting, were TPMT3A carriers. CONCLUSION: In this observational study, the absence of response, probably due to the low-dose scheme used, was the major cause of AZA withdrawal in our series of RA patients. TPMT genotyping may allow the use of high doses of AZA in patients with normal TPMT alleles to improve the efficacy of this immunosuppressive drug. Our data support the relationship between gastrointestinal intolerance and thiopurine metabolic imbalance.     

Thiopurine-methyltransferase variants in inflammatory bowel disease:Prevalence and toxicity in Brazilian patients

AIM:To analyze the prevalence of thiopurine-methyltransferase(TPMT)genotypes and their associationwith drug toxicity in inflammatory bowel disease(IBD)patients from southeastern Brazil.METHODS:A total of 219 consecutive patients with IBD,of which 146 had Crohn’s disease and 73 had ulcerative colitis,regularly seen at the outpatient unit of the Division of Gastroenterology at the University Hospital Pedro Ernesto of the State University of Rio de Janeiro,a tertiary referral center,were enrolled in this study from February 2009 to January 2011.We analyzed the presence of major TPMT genetic variants(TPMT*2,*3A,*3C)in IBD patients by means of a specific allele and RFLP-PCR.Genomic DNA was isolated from peripheral blood leukocytes by proteinase-K/Sodium Dodecyl Sulfate digestion and phenol-chloroform extraction.TPMT*2(C238G),TPMT*3A(G460A/A719G),and TPMT*3C(A719G)genotypes were detected by real-time polymerase chain reaction followed by direct sequencing with specific primers.Clinical data were systematically recorded,and correlated with the genotype results.RESULTS:The distribution of the selected TPMT gene polymorphism TPMT*2(C238G),TPMT*3A(G460A/A719G),and TPMT*3C(A719G)genotypes was 3.6%,5.4%,and 7.7%of the patients,respectively.Among the side effects recorded from patients taking azathioprine,14 patients presented with pancreatitis and/or an elevation of pancreatic enzymes,while 6 patients had liver toxicity,and 2 patients exhibited myelosuppression/neutropenia.TPMT polymorphisms were detected in 37/219 patients(8 heterozygous for*2,11 heterozygous for*3A,and 18 heterozygous for*3C).No homozygotic polymorphisms were found.Despite the prevalence of the TPMT*3C genotype,no differences among the genotype frequencies were significant.Although no association was detected regarding myelotoxicity or hepatotoxicity,a trend towards the elevation of pancreatic enzymes was observed for TPMT*2 and TPMT*3C genotypes.CONCLUSION:The prevalence of TPMT genotypes was high among Brazilian patients.Variants genes*2and*3C may be associated with azathioprine pancreatic toxicity in a IBD southeastern Brazilian population.     

广州地区人群中硫嘌呤甲基转移酶基因的等位基因频率及分布

目的：了解硫嘌呤甲基转移酶(Thiopurme S-methyltransferase，TPMT)基因常见的遗传多态性在广州地区人群中的分布及其频率。方法：应用聚合酶链反应-等位基因特异性扩增(PCR-ASA)和聚合酶链反应-限制性片段长度多态性分析(PCR-RFLP)对文献报道的TPMT基因中三种常见的基因突变(G238C、G460A和A719G)进行检测。结果：在我们调查的人群中只检测到A719G(TPMT／3C)，其频率为0．7％(3／392)；该突变基因在人群中以杂合子形式存在，基因型频率为1．5％(3／196)，未发现突变型纯合子，亦未检测到另外两种基因突变。结论：广州地区人群中TPMT等位基因的频率及分布与白人存在明显差异，与黑人及日本人较为接近，但频率更低。     

HRM技术检测炎症性肠病患者TPMT的基因多态性

目的应用HRM技术检测炎症性肠病(IBD)患者TPMT基因多态性,进而探索IBD患者TPMT基因型与硫唑嘌呤(AZA)致骨髓抑制的关系。方法采用聚合酶链反应-高分辨熔解曲线(PCR-HRM)与Sanger法序列测定相结合的方法,对82例IBD患者和53名健康志愿者TPMT基因第7、10外显子进行检测。结果 IBD患者中TPMT*1/*3C杂合子4例,健康对照者中TPMT*1/*3C杂合子2例。未检测出TPMT*3A和TPMT*3B型突变。IBD患者4例出现骨髓抑制的患者中,1例是TPMT*1/*3C杂合子;其余3例为TPMT野生型。结论 TPMT*3C(A719G)基因突变在中国的IBD患者中较TPMT*3A(G460A/A719G)、TPMT*3B(G460A)发生率高,而存在此基因突变的IBD患者对硫唑嘌呤不能耐受,导致骨髓抑制。然而TPMT基因突变只能解释部分AZA治疗IBD导致骨髓抑制的病例。     

Thiopurine S-methyltransferase (TPMT) Activity Is Better Determined by Biochemical Assay Versus Genotyping in the Jewish Population

Background

Thiopurine S-methyltransferase (TPMT) is a key enzyme that deactivates thiopurines, into their inactive metabolite, 6-methylmercaptopurine. Intermediate and low TPMT activity may lead to leukopenia following thiopurine treatment. The aim of this study was to determine TPMT activity and TPMT alleles (genotype–phenotype correlation) in Jews, aiming to develop an evidence-based pharmacogenetic assay for this population.

Methods

TPMT activity was determined in 228 Jewish volunteers by high performance liquid chromatography. Common allelic variants in the Caucasian population [TPMT*2 (G238C), TPMT *3A (G460A and A719G), TPMT* 3B (G460A) and TPMT*3C (A719G)] were tested. Phenotype–genotype correlation was examined and discordant cases were fully sequenced to identify novel genetic variants.

Results

Mean TPMT activity was 15.4 ± 4 U/ml red blood cells (range 1–34). Intermediate activity was found in 33/228 (14 %) subjects and absent activity was found in one sample (0.4 %). Only eight individuals (3.5 % of the entire cohort and 24 % of those with intermediate/low activity) were identified as carriers of a TPMT genetic variant, all of whom had the TPMT*3A allele. Sequencing the entire TPMT coding region and splice junctions in the remainder of the discordant cases did not reveal any novel variants.

Conclusion

Genotyping TPMT in Jews yields a much lower rate of variants than identified in the general Caucasian population. We conclude that a biochemical assay to determine TPMT enzymatic activity should be performed in Jews before starting thiopurine treatment in order to identify low activity subjects.     

Thiopurine methyltransferase genotyping in Palestinian childhood acute lymphoblastic leukemia patients

Background

The genetic polymorphism of thiopurine methyltransferase (TPMT) is well characterized in most populations. Four common polymorphic alleles are associated with impaired activity of the enzyme. These are TPMT*2 (238G>C), TPMT*3B (c.460G>A), TPMT*3A (c.460G>A and c.719A>G) and TPMT*3C (c.719A>G). The aim of the present study was to determine the frequency of TPMT polymorphisms and their association with the occurrence of adverse events, during 6-mercaptopurine therapy in pediatric acute lymphoblastic leukemic (ALL) patients in Gaza Strip.

Methods

A total of 56 DNA samples from all pediatric ALL patients admitted to the pediatric hematology departments of Gaza strip hospitals were analyzed. Genomic DNA from peripheral blood leukocytes was isolated and the TPMT*2, TPMT*3B TPMT*3A and TPMT*3C allelic polymorphism was determined by PCR-RFLP and allele specific PCR technique.

Results

No TPMT*2, *3B or *3C alleles were detected. Only one, out of 56 patients, was found heterozygous for the TPMT*3A allele. Thus, the frequency of TPMT*3A allele was calculated to be 0.89%. Fourteen patients of ALL were suffering from myelotoxicity during 6-MP therapy. From our results, no significant association could be established between clinical and laboratory data and/or the presence of the mutation in TPMT gene.

Conclusion

TPMT*3A was the only deficiency allele detected in our population with an allelic frequency of 0.89%. Other polymorphic alleles in TPMT gene, or factors other than TPMT polymorphisms may be responsible for the development of myelosuppression in cases that don’t carry the investigated TPMT alleles (*2, *3A, *3B and *3C). Therefore, more studies are recommended to study such factors.     

Inosine triphosphate pyrophosphatase and thiopurine s-methyltransferase genotypes relationship to azathioprine-induced myelosuppression.

BACKGROUND & AIMS: The use of azathioprine (AZA) in inflammatory bowel disease (IBD) patients is limited by toxicity, which occurs in up to 20% of treated patients. Mutations in the thiopurine S-methyltransferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) genes have been associated with the occurrence of AZA-related toxicity. The aim of our study was to determine the relative contribution of ITPA and TPMT mutations to the development of toxicity induced by AZA treatment in IBD patients. METHODS: ITPA(94C>A, IVS2+21A>C) and TPMT (238G>C, 460G>A, and 719A>G) genotypes were assessed in 262 IBD patients (159 females, 103 males; 67 patients with ulcerative colitis, 195 patients with Crohn's disease) treated with AZA and were correlated with the development of leukopenia and hepatotoxicity. RESULTS: Leukopenia (leukocyte count, <3.0 x 10(9)/L) was observed in 4.6% of treated patients. The frequencies of mutant ITPA 94C>A and TPMT alleles were significantly higher in the leukopenic population compared with patients without leukopenia (16.7% and 5.4%, respectively, for ITPA 94C>A, and 20.8% and 4%, respectively, for TPMT). Moreover, the ITPA 94C>A and TPMT mutations predicted leukopenia: ITPA 94C>A odds ratio, 3.504; 95% confidence interval, 1.119-10.971 (P = .046); TPMT odds ratio, 6.316; 95% confidence interval, 2.141-18.634 (P = .004). Neither TPMT nor ITPA genotype predicted hepatotoxicity. CONCLUSIONS: ITPA 94C>A and TPMT polymorphisms are associated with AZA-related leukopenia in IBD patients.     

Significant differences in the interleukin-1beta and interleukin-1 receptor antagonist gene polymorphisms in a Hungarian population with inflammatory bowel disease

BACKGROUND: There is growing evidence of the importance of genetic predisposition and the activation of the mucosal immune system in the pathogenesis of inflammatory bowel disease. Thus, genes involved in the regulation of inflammation are receiving increased attention. We have studied whether Crohn's disease (CD) or ulcerative colitis (UC) is associated with certain allelic combinations of IL1B/IL1RA gene polymorphisms in a different European population than the ones studied so far. METHODS: Ninety-six patients with UC, 97 with CD, and 132 healthy individuals (HC) were typed for the polymorphic regions in exon 5 of the IL1B gene and in intron 2 of the IL1RA gene, using polymerase chain reaction-based methods. RESULTS: In CD homozygotes for allele 1 in IL1B gene polymorphism were more often present (72% versus 28%; P = 0.01) in the subgroup of patients carrying at least one copy of allele 2 in IL1RA gene polymorphism. This association was not found in HC (HC versus CD; P = 0.03) or UC. However, in UC patients with pancolitis a similar trend was observed (75% versus 25%). Several genotype combinations characterized by the presence of allele 2 of the IL1RA gene polymorphism were more common in CD (P = 0.001) and UC (P = 0.049) than in HC. CONCLUSIONS: Our data support the concept that CD and severe UC have a genetic disequilibrium in the distribution of IL1B and IL1RA gene polymorphisms. These findings together with functional studies will contribute to the understanding of the pathogenesis of the chronicity of inflammation in these diseases.     

Genotypic analysis of thiopurine S-methyltransferase in patients with Crohn's disease and severe myelosuppression during azathioprine therapy

BACKGROUND & AIMS: Myelosuppression in patients with Crohn's disease (CD) treated with azathioprine has been attributed to low activity of thiopurine S-methyltransferase (TPMT). Allelic variants of the TPMT gene responsible for changes in the enzyme activity have been characterized. We investigated the distribution of mutant alleles associated with TPMT deficiency in patients with CD and myelosuppression during azathioprine/6-mercaptopurine therapy. METHODS: Forty-one patients with CD were included. They developed leukopenia or thrombocytopenia during azathioprine or 6-mercaptopurine treatment. Polymerase chain reaction-based methods were used to search for mutations associated with TPMT deficiency. RESULTS: Four patients (10%) had 2 mutant alleles associated with TPMT deficiency, 7 (17%) had 1 mutant allele, and 30 (73%) had no known TPMT mutation. The delay between administration of the drug and occurrence of bone marrow toxicity was less than 1.5 months in the 4 patients with 2 mutant alleles, and ranged from 1 to 18 months in patients with 1 mutant allele and from 0.5 to 87 months in patients with normal genotype. CONCLUSIONS: Twenty-seven percent of patients with CD and myelosuppression during azathioprine therapy had mutant alleles of the TPMT gene associated with enzyme deficiency. Myelosuppression is more often caused by other factors. Continued monitoring of blood cell counts remains mandatory in patients treated with azathioprine.     

High prevalence of polymorphism and low activity of thiopurine methyltransferase in patients with inflammatory bowel disease

BackgroundGene polymorphism of thiopurine methyltransferase (TPMT) correlates with decreased enzyme activity which determines a significant risk of adverse effect reactions (ADR) in patients treated with thiopurines. The aim of this study was to investigate TPMT genotype and phenotype status in patients with inflammatory bowel diseases (IBD).MethodsFifty-one consecutive out-patients with IBD were genotyped for the following allelic variants: rs1800462 (referred as TPMT*2 allele), rs1800460 (referred as TPMT *3B allele), and 1142345 (referred as TPMT *3C allele). Red blood cell TPMT activity was measured using a competitive micro-well immunoassay for the semi-quantitative determination of TPMT activity in red blood cells (RBC) by means of a 6-MP substrate.ResultsPolymorphism of TPMT was found in 5 out of 51 patients (10%; 95% CI 2%–18%), three heterozygous and two homozygous carriers. Six patients (11.8%; 95% CI 2.4%–19.5%) displayed very low, 12 (23.5%; 95% CI 11.4%–34.5%) intermediate, and 33 (64.7%; 95% CI 52%–78%) normal/high TPMT activity. There were no differences between TPMT genotype and phenotype groups according to age, type of disease, smoking, and chronic medications. A 71% (95% CI 61%–81%; κ = 0.45) concordance rate was found between genotype and phenotype status. Six out of 27 (22%) current or past users of azathioprine developed ADR, with three (50%) displaying TPMT genotype and/or phenotype alterations.ConclusionCompared to the general population, IBD patients may have significantly higher prevalence of TPMT polymorphism and, even more, low activity. Phenotypic more than genotypic TPMT analysis could be useful to better manage IBD therapy with thiopurines.     

Significant Differences in the Interleukin-1ß and Interleukin-1 Receptor Antagonist Gene Polymorphisms in a Hungarian Population with Inflammatory Bowel Disease

Background: There is growing evidence of the importance of genetic predisposition and the activation of the mucosal immune system in the pathogenesis of inflammatory bowel disease. Thus, genes involved in the regulation of inflammation are receiving increased attention. We have studied whether Crohn's disease (CD) or ulcerative colitis (UC) is associated with certain allelic combinations of IL1B/IL1RA gene polymorphisms in a different European population than the ones studied so far. Methods: Ninety-six patients with UC, 97 with CD, and 132 healthy individuals (HC) were typed for the polymorphic regions in exon 5 of the IL1B gene and in intron 2 of the IL1RA gene, using polymerase chain reaction-based methods. Results: In CD homozygotes for allele 1 in IL1B gene polymorphism were more often present (72% versus 28%; P = 0.01) in the subgroup of patients carrying at least one copy of allele 2 in IL1RA gene polymorphism. This association was not found in HC (HC versus CD; P = 0.03) or UC. However, in UC patients with pancolitis a similar trend was observed (75% versus 25%). Several genotype combinations characterized by the presence of allele 2 of the IL1RA gene polymorphism were more common in CD (P = 0.001) and UC (P = 0.049) than in HC. Conclusions: Our data support the concept that CD and severe UC have a genetic disequilibrium in the distribution of IL1B and IL1RA gene polymorphisms. These findings together with functional studies will contribute to the understanding of the pathogenesis of the chronicity of inflammation in these diseases.     

Azathioprine-induced severe pancytopenia due to a homozygous two-point mutation of the thiopurine methyltransferase gene in a patient with juvenile HLA-B27-associated spondylarthritis

Severe pancytopenia due to azathioprine (AZA) toxicity in patients with autoimmune diseases is not uncommon. We describe a 14-year-old girl with HLA-B27+ spondylarthritis who was treated with AZA 3 mg/kg/day and who suddenly developed severe pancytopenia in the seventh week of treatment. Analysis of the catabolic pathway of AZA revealed a homozygous deficiency of thiopurine methyltransferase (TPMT) on the basis of a combined 2-point mutation at nucleotide positions 460 and 719 in the gene for TPMT, causing a toxic level of the metabolic active 6-thioguanine nucleotides (6-TGN) (2,394 pmoles/8 × 10⁸ red blood cells). The patient was transfusion dependent and finally recovered 8 weeks after the development of the pancytopenia. At that time, 6-TGN had already returned to normal therapeutic levels. Family studies revealed another homozygous deficiency in the mother, while the other family members were heterozygous.     

亚甲基四氢叶酸还原酶基因677和1298位点多态性与溃疡性结肠炎的相关性

目的 探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T和A1298C位点多态性与浙江汉族人群溃疡性结肠炎(UC)的关系.方法 采用限制性片段长度多态性PCR(PCR-RELP)法,在274例UC患者和726例正常对照者中检测MTHFR C677T及A1298C基因多态性分布差异.结果 UC患者中,MTHFR C677T突变等位基因(T)和基因型(CT+TT)频率与正常对照组相比差异无统计学意义(P＞0.05);而MTHFR A1298C突变等位基因(C)和基因型(AC+CC)频率均高于正常对照组(35.77%比29.96%,P=0.013;52.19%比44.90%,P=0.039).另外,MTHFR 677纯合子突变基因型(TT)、突变等位基因(T)以及677CT/1298AC复合基因型频率在广泛性结肠炎患者中明显高于远端结肠炎(37.66%比14.72%,P=0.0002;49.35%比32.99%,P=0.0004;29.87%比15.23%,P=0.006);重度UC患者的MTHFR 1298位点突变等位基因(C)频率显著低于(轻+中)度患者(18.97%比33.88%,P=0.022).结论 MTHFR C677T及A1298C基因多态性与浙江汉族UC明显相关.

Abstract：

Objective To investigate the association between the genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and ulcerative colitis (UC) of Han ethnic population in Zhejiang, China. Methods Two hundred and seventy-four consecutive patients with UC and 726 healthy controls (HC) were studied. The genetic polymorphisms of MTHFR (C677T and A1298C) were genotyped using PCR-RELP methods. Results The frequencies of variant allele and genotype in MTHFR A1298Cgene were higher in UC patients than in the HC (35.77% vs 29. 96%, P =0. 013; 52. 19% vs 44. 90%,P=0.039; respectively). However, there were no significant discrepancies of the allele and genotype frequencies in the MTHFR C677T gene between the UC patients and the HC (P ＞ 0. 05 ). In addition, the MTHFR 677Tr homozygote, T allele and 677CT/1298AC compound genotype were more prevalent in patients with extensive colitis than in those with distal colitis (37. 66% vs 14. 72% ,P = 0. 0002; 49. 35% vs 32.99% ,P =0. 0004; 29. 87% vs 15.23% ,P =0. 006; respectively). Furthermore,the variant allele in the MTHFR A1298C gene (C) in severe UC patients was significantly lower than in mild and moderate UC patients (18.97% vs 33. 88% ,P =0. 022). Conclusion The genetic polymorphisms of MTHFR C677T and A1298C are obviously associated with Han ethnic population with UC in Zhejiang province.     

Association between polymorphisms in the Toll-like receptor 4, CD14, and CARD15／NOD2 and inflammatory bowel disease in the Greek population

AIM: Crohn's disease (CD) and ulcerative colitis (DC) are multifactorial diseases with a significant genetic background. Apart from CARD15/NOD2 gene, evidence is accumulating that molecules related to the innate immune response such as CD14 or Toll-like receptor 4 (TLR4), are involved in their pathogenesis. In further exploring the genetic background of these diseases, we investigated the variations in the CARD15/NOD2 gene (Arg702Trp, Gly908Arg and Leu1007fsinsC), and polymorphisms in the TLR4 gene (Asp299Gly and Thr399Ile) as well as in the promoter of the CD14 gene (T/C at position -159) in Greek patients with CD and UC. METHODS: DNA was obtained from 120 patients with CD, 85 with UC and 100 healthy individuals. Genotyping was performed by allele specific PCR or by PCR-RFLP analysis. RESULTS: The 299Gly allele frequency of the TLR4 gene and the T allele and TT genotype frequencies of the CD14 promoter were significantly higher in CD patients only compared to healthy individuals (P= 0.026<0.05; P= 0.0048<0.01 and P= 0.047<0.05 respectively). Concerning the NOD2/CARD15 mutations the overall presence in CD patients was significantly higher than that: in UC patients or in controls. Additionally, 51.67% of the CD patients were carriers of a TLR4 and/or CD14 polymorphic allele and at least one variant of the NOD2/CARD15, compared to 27% of the UC patients. It should be pointed out that both frequencies significantly increased as compared with the 10% frequency of multiple carriers found in healthy controls. A possible interaction of the NOD2/CARD15 with TLR4 and especially CD14, increased the risk of developing inflammatory bowel disease (IBD). CONCLUSION: Our results indicate that co-existence of a mutation in either the TLR4 or CD14 gene, and in NOD2/CARD15 is associated with an increased susceptibility to developing CD compared to UC, and to developing either CD or UC compared to healthy individuals.     

肿瘤坏死因子相关凋亡诱导配体基因多态性及单倍型与溃疡性结肠炎易感性相关性研究

[目的]探讨肿瘤坏死因子相关凋亡诱导配体(Trail) (G1525A、C1595T)基因多态性及单倍型与溃疡性结肠炎(UC)易感性的关系.[方法]收集252例UC患者和775例正常对照者(HC),采用直接测序法检测Trail (G1525A、C1595T)等位基因及基因型,并做单倍型分析.[结果]与HC组相比,UC组Trail GI525A变异等位基因(A)和基因型(GA+AA)的频率明显减低(35.52％ VS 55.94％,P＜0.01；41.27％ VS 79.74％,P＜0.01) ;Trail C1595T变异基因型(CT+TT)的频率UC组亦明显降低(70.23％ VS 80.52％,P＜0.01).单倍型分析发现Trail (G1525A、C1595T)完全连锁(D’=0.979,r2=0.810).与HC组比较,GC、GT单倍型UC组明显增高(46.56％VS 36.77％,P＜0.01；13.36％ VS 7.54％,P＜0.01)；而AC、AT单倍型明显降低(0.64％ VS 10.22％,P＜0.01；39.44％ VS 45.47％,P＜0.01).[结论]Trail(G1525A、C1595T)基因多态性及单倍型与UC易感性相关,此2位点基因变异对UC可能具有保护作用.     

Thiopurine S-methyltransferase and inosine triphosphate pyrophosphohydrolase genes in Japanese patients with inflammatory bowel disease in whom adverse drug reactions were induced by azathioprine/6-mercaptopurine treatment

Background  The main cause of azathioprine (AZA)/6-mercaptopurine (6MP)-induced adverse reactions is a reduction in the activities of the metabolizing enzymes thiopurine S-methyltransferase (TPMT) and inosine triphosphate pyrophosphohydrolase (ITPA). Adverse reactions develop at a high frequency in Japanese patients at half the dose required for European and American patients; however, the association with TPMT and ITPA gene polymorphisms in Japanese has not been fully investigated. Methods  Gene mutations of TPMT and ITPA, the major AZA/6-MP -metabolizing enzymes, were investigated retrospectively in 16 Japanese patients with inflammatory bowel disease (IBD) in whom AZA/6MP treatment induced adverse reactions. Results  The TPMT gene was found to have a wild-type sequence in all patients, but in the ITPA gene a mutation, 94C>A, was detected at a rate of 50% (8/16), with 83.3% (5/6) occurring in patients with acute bone marrow suppression and 75% (3/4) in those with agranulocytosis. The 94C>A allele frequency was 10 of 32 (0.313; 95% CI, 0.180–0.486). Adverse reactions developed earlier in patients with the 94C>A mutation. However, in half the patients, no gene polymorphism was noted. Conclusions  It is suggested that the ITPA gene mutation is closely related to the adverse reactions of AZA/6-MP in Japanese patients, and screening for the mutant allele is useful for predicting the most serious adverse reactions, agranulocytosis and acute bone marrow suppression.     

Thiopurine S-methyltransferase polymorphisms and the relationship between the mutant alleles and the adverse effects in systemic lupus erythematosus patients taking azathioprine

OBJECTIVE: The present study sought to elucidate the genetic basis of thiopurine methyltransferase (TPMT) polymorphism and subsequently to investigate the relationship between mutant TPMT and an adverse response observed in Korean patients with systemic lupus erythematosus (SLE) taking azathioprine (AZA). METHODS: The TPMT genotype of 342 patients with SLE was determined by MALDI-TOF mass spectrometry and correlated with the effects of clinical exposure to AZA. RESULTS: TPMT polymorphism was detected in 17 of the 342 study subjects (5.0%), 12 heterozygous for the TPMT*3C allele and 5 heterozygous for the TPMT*6 allele. Numerous patients taking AZA demonstrated adverse drug responses. Severe nausea occurred in 4 patients with the TPMT*3C allele, while 1 patient with the TPMT*6 allele suffered severe bone marrow toxicity. Leucopenia (n = 17), nausea (n = 4), and abnormal liver function (n = 1) were suspected in 23 of the 94 lupus patients taking AZA. AZA was relatively well tolerated by the remainder of the patients. The heterozygous genotype for the TPMT*3C and *6 alleles was frequently detected in Korean SLE patients. CONCLUSION: Contrary to previous hypotheses, this study identified no statistical correlation between TPMT genotype and AZA toxicity. We thus conclude that TMPT genotyping cannot replace regular blood monitoring in SLE patients receiving AZA treatment.     

Carotid and femoral intima-media thickness in relation to three candidate genes in a Caucasian population

BACKGROUND : In a Caucasian population, the prevalence and incidence of hypertension, renal function and large artery stiffness were significantly correlated with polymorphisms in the genes encoding the angiotensin-converting enzyme (ACE I/D), aldosterone synthase (-C344T) and the cytoskeleton protein alpha-adducin (Gly460Trp). OBJECTIVE : This study investigated intima-media thickening, a precursor of atherosclerosis, in relation to these genetic polymorphisms. METHODS : Carotid and femoral intima-media thickness were assessed with a wall-track system in 380 subjects enrolled in a population study. Subjects were genotyped for the presence of the ACE D, aldosterone synthase -344T and alpha-adducin 460Trp alleles. The statistical analysis allowed for confounders, interactions among genes, and the non-independence of the phenotypes within families. RESULTS : The sample included 188 men (49.5%). Mean age was 39.8 years. Intima-media thickness of the carotid and femoral arteries averaged 575 and 719 microm, respectively. Intima-media thickness of the femoral-but not carotid-artery increased with the number of ACE D alleles. The effect of ACE genotype on femoral intima-media thickness was confined to carriers of the 460Trp allele and the -344T allele. Expressed as a percentage of the population mean, the mean differences between II and DD homozygotes averaged 13.4% (95% CI 5.6-21.2%) in all subjects, 21.2% (8.0-34.5%) in carriers of the 460Trp allele, 15.4% (4.1-26.8%) in carriers of the -344T allele, and 25.2% (10.7-39.7%) if the 460Trp and -344T alleles were both present. CONCLUSION : This study shows that a relationship exists between the intima-media thickness of the large muscular femoral artery and the ACE gene. This relationship is only apparent in the presence of either the alpha-adducin 460Trp or the aldosterone synthase -344T allele. These findings may have clinical implications for the assessment of genetic cardiovascular risk.     

溃疡性结肠炎患者中肿瘤坏死因子相关凋亡诱导配体基因多态性及单倍型分析

目的 探讨肿瘤坏死因子相关凋亡诱导配体(Trail)基因多态性及单倍型与溃疡性结肠炎(UC)的关系.方法 收集UC患者331例,健康对照者832名,PCR扩增Trail目的基因后,直接测序检测Trail基因3非编码区(G1525A/G1588A/C1595T)三种单核苷酸多态性,并分析Trail单倍型与UC的关系.结果 与对照组相比较,Trail G1525A突变等位基因A和基因型GA+ AA的频率在UC组中明显降低(P值均＜0.01);UC组Trail G1588A和C1595T两位点突变等位基因A和T的频率明显低于对照组,且差异有统计学意义(P值均＜0.01).轻和中度UC患者Trail C1595T突变等位基因T和CT+ TT基因型频率为49.15％和64.51％,重度UC患者分别为72.37％和84.21％,两组比较差异均有统计学意义(OR值分别=2.710和2.935,95％CI:1.598～4.596和1.188～7.249,P值均＜0.05).重度UC患者Trail G1525A突变等位基因A的频率为48.69％,较轻和中度UC患者(35.16％)增加(OR=1.750,95％CI:1.082～2.830,P=0.021).UC组中AAT单倍型频率显著低于对照组(43.09％比58.41％,95％CI:1.549～2.229,P＜0.01);GAT单倍型频率在UC组中明显增高(10.15％比0.18％,95％CI:0.005～0.051,P＜0.01).结论 Trail基因多态性及单倍型与UC易感性密切相关.     

DLG5 R30Q is not associated with IBD in Hungarian IBD patients but predicts clinical response to steroids in Crohn's disease

BACKGROUND: Recent data suggest that haplotypic variants of the DLG5 gene on 10q23 are associated with susceptibility to inflammatory bowel disease (IBD) in Germany. In view of the geographical differences in frequency of genetic markers and the absence of data in Central European patients, our aim was to determine the DLG5 R30Q variant in Hungarian IBD patients. MATERIALS AND METHODS: We investigated 773 unrelated IBD patients (age 38.1 +/- 10.3 years; duration, 8.8 +/- 7.5 years; Crohn's disease [CD]: 639; male/female, 309/330; duration, 8.4 +/- 7.1 years; ulcerative colitis [UC]: 134; male/female, 63/71; duration, 10.6 +/- 8.9 years) and 150 healthy subjects. DLG5 R30Q and TLR4 D299G variants were tested by polymerase chain reaction/restriction fragment length polymorphism. DNA was screened for NOD2/CARD15 mutations by denaturing high-performance liquid chromatography. Detailed clinical phenotype was determined by reviewing the medical charts. RESULTS: The frequency of the R30Q variant allele was not significantly different in IBD (22.0%), CD (20.8%), and UC (27.6%) patients compared with healthy control subjects (28.0%). In CD, the 113A variant allele was associated with steroid resistance (16.3% vs noncarriers, 7.6%; odds ratio [OR], 2.4; 95% CI 1.3-4.5; P = 0.013). In a logistic regression model carriage of DLG5 R30Q, perianal involvement and frequent relapses were independently associated with steroid resistance. No phenotype-genotype associations were found in UC patients, although a trend toward more extensive disease was observed in carriers of the variant allele (OR = 2.1; 95% CI 0.95-4.4; P = 0.07). CONCLUSIONS: The present data strongly contrast previous data from Germany. DLG5 113A is not associated with disease susceptibility, but there was a tendency for this allele to confer resistance to steroids. Further studies are required to evaluate the significance of DLG5 in other populations from geographically diverse regions.