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1.
The enzyme inosine triphosphate pyrophosphatase (ITPase) catalyses the pyrophosphohydrolysis of ITP to IMP. ITPase deficiency is a clinically benign autosomal recessive condition characterised by the abnormal accumulation of ITP in erythrocytes. A deficiency of ITPase may predict adverse reactions to therapy with the thiopurine drug 6‐mercaptopurine and its prodrug azathioprine. In this study, we examine the frequencies of ITPA polymorphisms in 100 healthy Japanese individuals. The allele frequency of the 94C > A variant in the Japanese sample was 0.135 (Caucasian allele frequency 0.06). The IV2 + 21A > C polymorphism was not found in Japanese (Caucasian allele frequency 0.130). Allele frequencies of the 138G > A, 561G > A and 708G > A polymorphisms were 0.57, 0.18 and 0.06 respectively in the Japanese population, and with the exception of the 138G > A polymorphism, similar to allele frequencies in Caucasians.  相似文献   

2.
Genetic basis of inosine triphosphate pyrophosphohydrolase deficiency   总被引:12,自引:0,他引:12  
Inosine triphosphate pyrophosphohydrolase (ITPase) deficiency is a common inherited condition characterized by the abnormal accumulation of inosine triphosphate (ITP) in erythrocytes. The genetic basis and pathological consequences of ITPase deficiency are unknown. We have characterized the genomic structure of the ITPA gene, showing that it has eight exons. Five single nucleotide polymorphisms were identified, three silent (138G-->A, 561G-->A, 708G-->A) and two associated with ITPase deficiency (94C-->A, IVS2+21A-->C). Homozygotes for the 94C-->A missense mutation (Pro32 to Thr) had zero erythrocyte ITPase activity, whereas 94C-->A heterozygotes averaged 22.5% of the control mean, a level of activity consistent with impaired subunit association of a dimeric enzyme. ITPase activity of IVS2+21A-->C homozygotes averaged 60% of the control mean. In order to explore further the relationship between mutations and enzyme activity, we examined the association between genotype and ITPase activity in 100 healthy controls. Ten subjects were heterozygous for 94C-->A (allele frequency: 0.06), 24 were heterozygotes for IVS2+21A-->C (allele frequency: 0.13) and two were compound heterozygous for these mutations. The activities of IVS2+21A-->C heterozygotes and 94C-->A/IVS2+21A-->C compound heterozygotes were 60% and 10%, respectively, of the normal control mean, suggesting that the intron mutation affects enzyme activity. In all cases when ITPase activity was below the normal range, one or both mutations were found. The ITPA genotype did not correspond to any identifiable red cell phenotype. A possible relationship between ITPase deficiency and increased drug toxicity of purine analogue drugs is proposed.  相似文献   

3.

Background

Inosine triphosphatase (ITPase) is encoded by the polymorphic gene ITPA and maintains low intracellular levels of the inosine nucleotides ITP and dITP. The most frequently reported polymorphisms are ITPA c.94C>A (rs 1127354) and ITPA c. 124+21 A>C (rs7270101). Some nucleoside-analogues used in the treatment of HIV-seropositive (HIV+) patients are potential substrates for ITPase. Therefore, the frequency of ITPA SNPs and ITPase activity were studied in a population of HIV+-patients.

Methods

The study population consisted of 222 patients, predominantly Caucasian males, >95% using HAART. Erythrocyte ITPase activity was determined by measuring the formation of IMP from ITP. ITPA genotype was determined by sequencing genomic DNA. Distribution of ITPase activity, genotype-phenotype correlation and allele frequencies were compared to 198 control subjects. The effect of nucleoside analogues on ITPase activity was studied using lymphoblastic T-cell cultures and human recombinant ITPase. Enzyme kinetic experiments were performed on erythrocyte ITPase from HIV+ patients and controls.

Results

No difference was observed in the allele frequencies between the HIV+-cohort (± HAART) and the control population. HIV+ carriers of the wild type and ITPA c.94C>A had significantly lower ITPase activities than control subjects with the same genotype (p<0.005). This was not observed in ITPA c. 124+21 A>C carriers. Nucleoside analogues did not affect ITPase activity in cell culture and human recombinant ITPase. Conclusion: ITPA population genetics were identical in HIV+ and control populations. However, the majority of HIV+-patients had decreased erythrocyte ITPase activity compared to controls, probably due to decreased amounts of ITPase protein. It seems unlikely that ITPase activity is decreased due to nucleoside analogues (HAART). Long-term effects of HIV-infection altering ITPase protein expression or stability may explain the phenomenon observed.  相似文献   

4.
The role of inosine triphosphatase (ITPase) in adverse drug reactions associated with thiopurine therapy is still under heavy debate. Surprisingly, little is known about the way thiopurines are handled by ITPase. We studied the effect of ITPA polymorphisms on the handling of inosine triphosphate (ITP) and thioinosine triphosphate (TITP) to gain more insight into this phenomenon. Human erythrocyte ITPase activity was measured by incubation with ITP using established protocols, and the generated inosine monophosphate (IMP) was measured using ion-pair RP-HPLC. Molecular analysis of the ITPA gene was performed to establish the genotype. Kinetic parameters were established for the two common polymorphisms for both ITP and TITP as substrates using the above mentioned protocol. Both ITP and TITP are substrates for ITPase and their enzyme activities are comparable. Substrate binding is not altered in the different ITPA polymorphisms. It is shown that the velocity of pyrophosphohydrolysis is compromised when the c.94C > A polymorphism is present, both in the heterozygous and in the homozygous state. TITP is handled by ITPase in a similar way as for ITP, which implies that TITP will accumulate in the erythrocytes of patients with an ITPase deficiency, resulting in adverse drug reactions (ADRs) on thiopurine therapy. In carriers of ITPA polymorphisms, the matter is more complex and the development of ADR may depend on additional epigenetic factors rather than on the accumulation of thiopurinenucleotides.  相似文献   

5.
Dihydropyrimidine dehydrogenase enzyme (DPD) deficiency is a pharmacogenetic syndrome leading to severe side-effects in patients receiving therapies containing the anticancer drug 5-fluorouracil (5-FU). The aim of this population study is to evaluate gene variations in the coding region of the dihydropyrimidine dehydrogenase gene (DPYD) in the Tunisian population. One hundred and six unrelated healthy Tunisian volunteers were genotyped by denaturing HPLC (DHPLC). Twelve variants in the coding region of the DPYD were detected. Allele frequencies of DPYD*5 (A1627G), DPYD*6 (G2194A), DPYD*9A (T85C), A496G, and G1218A were 12.7%, 7.1%, 13.7%, 5.7%, and 0.5%, respectively. The DPYD alleles DPYD*2A (IVS 14+1g>1), DPYD*3 (1897 del C) and DPYD*4 (G1601A) associated with DPD deficiency were absent from the examined subjects. We describe for the first time a new intronic polymorphism IVS 6-29 g>t, found in an allelic frequency of 4.7% in the Tunisian population. Comparing our data with that obtained in Caucasian, Egyptian, Japanese and African-American populations, we found that the Tunisian population resembles Egyptian and Caucasian populations with regard to their allelic frequencies of DPYD polymorphisms. This study describes for the first time the spectrum of DPYD sequence variations in the Tunisian population.  相似文献   

6.

Background

Role of multidrug resistance-1 (MDR-1) gene polymorphisms has not been clarified in nephrotic syndrome (NS). Additionally, researchers studied several genetic polymorphisms to explain their influence on different patients' responses to steroid; however the data were inconsistent. Therefore, we aimed to investigate the association of MDR-1 gene polymorphisms [C1236T, G2677T/A, C3435T] and haplotypes with susceptibility to childhood nephrotic syndrome, and whether they influence steroid response.

Methods

We detected MDR-1 gene polymorphisms using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 138 NS patients and 140 age and sex matched healthy children.

Results

The frequencies of MDR1 G2677T/A GT, GA, TT + AA genotypes or T allele, MDR1 C3435T TT genotype, and T allele genotype frequencies were significantly increased in NS group. While no significant differences were observed in distributions of C1236T genotypes or allele between NS patients and healthy children. Moreover, steroid non-responder NS patients had significantly higher frequencies of MDR1 G2677T/A GT, GA, and TT + AA genotypes than steroid responsive NS patients. We observed also that NS patients with age less than 6 years old had increased frequencies of MDR1 G2677T/A GT, GA, TT + AA genotypes or T allele MDR1 C3435T CT, TT genotypes and T allele. Interestingly the frequency of the TGC haplotype of MDR1 was lower in the initial steroid responders than in non-responders NS patients. On the contrary, there were no any association between the MDR1 haplotypes with NS susceptibility and they did not influence renal pathological findings.

Conclusion

Our data suggested that MDR1 C3435T or G2677T/A gene polymorphisms are risk factors of increased susceptibility, earlier onset of NS, and steroid resistance.  相似文献   

7.
CD45 is crucial for normal lymphocyte signalling, and altered CD45 expression has major effects on immune function. Both mice and humans lacking CD45 expression are severely immunodeficient, and single-nucleotide polymorphisms in the CD45 gene that cause altered splicing have been associated with autoimmune and infectious diseases. Recently, we identified an exon 6 A138G polymorphism resulting in an increased proportion of activated CD45RO T cells and altered immune function. Here we report a significantly reduced frequency of the 138G allele in hepatitis C Japanese patients and a possibly reduced frequency in type I diabetes. The allele is widely distributed in the Far East and India, indicating that it may have a significant effect on disease burden in a large part of the human population.  相似文献   

8.
Diabetic nephropathy (DN), the most serious complication of Type 1 diabetes (DM1), has a strong genetic component. Cyclooxygenase-2 (COX-2), an inducible enzyme by a number of stimuli, has been implicated in pathophysiology of cardiovascular and renal disease, including DN. The allele -765C, of the -765G > C polymorphism (rs20417) in the COX-2 promoter has lower promoter activity compared with the -765G allele and protective effects in cardiovascular disease. This polymorphism was not investigated in patients with DM1 and nephropathy. The study was conducted in 779 Caucasian patients with DM1 and compared to a representative sample of healthy Czech population. The patients demonstrated lower frequencies of the CC genotype (P = 0.005). From the DM1 cohort, 153 patients met the criteria for low risk of the development of DN (LRDN, duration of DM1 > 10 years, normoalbuminuria, normotension) and 139 patients had manifest DN. There were no differences in -765G > C polymorphisms between LRDN and DN patients. Moreover, the C/G allele frequencies did not also differ between the groups. In conclusion, patients with DM1 display lower freqencies of the protective CC genotype as compared to healthy subjects. However, the study did not reveal associations of -765G > C polymorphism with the risk of DN.  相似文献   

9.
The difference in the allele frequencies of two single nucleotide polymorphisms (SNPs) in the second exon of the myoglobin gene between Japanese and other populations is reported. These SNPs are the substitutions of (A79G) and (T109C), and they were investigated by a single polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis followed by direct sequencing. The substitutions were always linked and two alleles were found in the samples used: the A-T allele with no substitution at positions (79A) and (109T) and the G-C allele with substitutions of (79G) and (109C). The frequencies of these alleles were 0.755 and 0.245, respectively, and they were found to be in Hardy-Weinberg equilibrium. The distribution of alleles in the Japanese population was significantly different from that reported among whites, blacks, and Hispanics (p < 0.0001).  相似文献   

10.
健康人群肿瘤坏死因子-α基因多态性的分析   总被引:1,自引:0,他引:1  
了解汉族健康人群中TNF-A基因多态性的分布,研究TNF-α表达与相关疾病之间的联系。采用PCR-限制性长度片段多态分析法检测140名重庆地区汉族健康人群的TNF—A-308,TNF—A-857位点基因多态性,计算其基因型和等位基因频率,结果显示TNF-A-308G/G、G/A、4朋基因型的频率分别为89%、11%、1%,其等位基因的发生频率以G等位基因最常见(93%),其次为A等位基因(7%)。TNF—A-857C/C、C/T、形,基因型的频率分别为68%、36%、8%,其等位基因发生频率以C等位基因最常见(81%),其次为T等位基因(19%)。由结果可以得出重庆地区汉族健康人群TNF—A-308位点存在G/A多态性,TNF-A-857位点存在C/T多态性。  相似文献   

11.
The complement system is an important mediator of natural and acquired immunity. The complement system genes coding complement proteins have polymorphisms. Hereditary deficiencies of this system predispose to autoimmune conditions such as age-dependent macular degeneration or impairment of immunity against microorganisms. When different populations are compared, the frequency of complement polymorphism shows a very marked geographical distribution. The frequency of the functional polymorphism rs2230199 (Arg80Gly; C > G) in the C3 gene was determined in population from south of Iran (n = 200), using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). One hundred thirty-eight persons (69 %) were homozygous for C allele (CC or SS); fifty-six person (28 %) heterozygote GC (FS) and six people were homozygous for G allele (GG or FF) (3 %). The allele frequency was 82 % for C3S and 18 % for C3F. A distribution of C3C allele frequency in our population is different from the reports of Asians (100 %); Indians (90-98 %); African-American (93 %); Africans (99 %) and south Brazilian (97 %). However, this finding is similar with the findings Caucasian (80-82 %) ( http://www.ncbi.nlm.nih.gov/SNP ); Americans (80 %); Pushtoon, Hazaras, Osbek and Tajik ethnic groups in Afghanistan (88-90 %) and Tunisian population (84 %). Our study confirmed significant inter-ethnic differences in C3 (rs2230199) frequencies between south Iranians and other ethnic groups. The analysis of genetic variation in complement genes is a tool to provide new insights into the evolution of the human immune system.  相似文献   

12.
Human cytochrome P450 2J2 (CYP2J2) is abundant in cardiovascular tissue and active in the metabolism of arachidonic acid to eicosanoids that have potent vasodilatory properties. Variability of the CYP2J2 gene is highly constrained except for its proximal promoter: there is a relatively common and functionally relevant single nucleotide polymorphism, indicated by -50G > T polymorphism (CYP2J2*7). Although genetic variation is known among ethnic groups, data for allele frequency are limited to a few Caucasian, Asian, and one African populations. In the present study, genotype distribution of CYP2J2*7 polymorphisms was investigated using polymerase chain reaction and restriction fragment length polymorphism assay in Japanese (n = 338), Mongolian (n = 118), and Ovambo (n = 186) populations and the findings compared with other populations. The mutant (CYP2J2*7) frequencies in the Japanese, Mongolians, and Ovambos were 0.0621, 0.0339, and 0.0672, respectively. Except for the Taiwanese, a general uniformity in the polymorphism in the Asian populations was observed. The mutation frequency of Ovambos was relatively lower than that of the African-American population. This study is the first to investigate the distribution of the CYP2J2*7 gene polymorphisms in Japanese, Mongolians, and Ovambos. These data will be informative and facilitate genetic association studies, in Asian and African populations for CYP2J2-related diseases such as cardiovascular disorders.  相似文献   

13.
14.
Uncoupling protein 2 (UCP2) is a member of the mitochondrial transporter superfamily. It is proposed as a candidate gene for obesity. A common G/A polymorphism in the promoter region of this gene is associated with enhanced adipose tissue mRNA expression in vivo. Using a PCR-RFLP method, we genotyped the UCP2 -866G/A polymorphism in 75 unrelated nonobese nondiabetic Iranians. The frequencies of the UCP2 -866G/A genotypes in 75 Iranian normal subjects were 7 (9.4%) for AA, 41 (54.6%) for GA, and 27 (36%) for GG. Significantly higher HDL cholesterol was detected in people with the GG genotype (p = 0.02) compared to individuals with the GA and AA genotypes. The frequency distribution results were compared with data from Japanese, Italians, Germans, Austrians, and Danes. Our allele frequencies were significantly different from the Japanese data from two different reports (P < 0.025) but not from the others. The Japanese data showed a higher frequency of the AA genotype, which is associated with a low prevalence of obesity, than the Caucasian individuals' data did. In conclusion, a single nucleotide polymorphism in the promoter region of the UCP2 gene has a significant association with HDL cholesterol level in Iranian nonobese nondiabetic subjects. Also, our allele-frequency distribution for this single nucleotide polymorphism is closer to European Caucasians than to Japanese in nonobese nondiabetic individuals.  相似文献   

15.
Inosine triphosphate pyrophosphatase (ITPase) deficiency occurs with polymorphic frequencies in Caucasians and results in the benign accumulation of the inosine nucleotide ITP. In 62 patients treated with azathioprine for inflammatory bowel disease, the ITPA 94C > A deficiency‐associated allele was significantly associated with adverse drug reactions (OR 4.2, 95% CI 1.6–11.5, p = 0.0034). Significant associations were found for flu‐like symptoms (OR 4.7, 95% CI 1.2–18.1, p = 0.0308), rash (OR 10.3, 95% CI 4.7–62.9, p = 0.0213) and pancreatitis (OR 6.2,CI 1.1–32.6, p = 0.0485). Polymorphism in the ITPA gene thus predicts AZA intolerance. Alternative immunosuppressive drugs, particularly 6‐thioguanine, should be considered for AZA‐intolerant patients with ITPase deficiency.  相似文献   

16.
Inosine triphosphate pyrophosphatase (ITPase) deficiency occurs with polymorphic frequencies in Caucasians and results in the benign accumulation of the inosine nucleotide ITP. In 62 patients treated with azathioprine for inflammatory bowel disease, the ITPA 94C>A deficiency-associated allele was significantly associated with adverse drug reactions (OR 4.2, 95% CI 1.6-11.5, p = 0.0034). Significant associations were found for flu-like symptoms (OR 4.7, 95% CI 1.2-18.1, p = 0.0308), rash (OR 10.3, 95% CI 4.7-62.9, p = 0.0213) and pancreatitis (OR 6.2, CI 1.1-32.6, p = 0.0485). Polymorphism in the ITPA gene thus predicts AZA intolerance. Alternative immunosuppressive drugs, particularly 6-thioguanine, should be considered for AZA-intolerant patients with ITPase deficiency.  相似文献   

17.
The allele and genotype distribution of two alcohol dehydrogenase genes ADH1B (exon 3 polymorphism A/G (47His)), ADH7 (intron 5 polymorphism G/C) and cytochrome P450 2E1 gene (CYP2E1; 5'-flanking region G/C and intron 6 T/A polymorphisms) were examined in Russian (Tomsk, n = 125) healthy population and in coronary atherosclerosis patients (CA, n = 92). The genotype frequencies followed the Hardy-Weinberg equilibrium and the alleles were in linkage equilibrium or gametic equilibrium in the control sample. Only two CYP2E1 gene polymorphisms were in linkage disequilibrium. The frequencies of the derived alleles at ADH1B (*G (+MslI) allele), CYP2E1 (**C2 (+PstI) allele) and CYP2E1 (*C (-Dra I)2 allele) were 8.48 +/- 1.86%; 1.20 +/- 0.69% and 10.00 +/- 1.90%, respectively. The 2ADH7 gene polymorphism showed a high level of heterozygosity; the frequency of the ADH7*C (-Sty I) allele was 44.58 +/- 3.21%. A significantly higher frequency of CYP2E1 (*C2 (+Pst I)) allele has been revealed in the CA group (P = 0.043; OR = 4.23; 95% CI 1.03-20.01). The tendency to significant effect of A1A2 genotype in ADH1B Msl 1 polymorphism was observed for systolic blood pressure in the control group (P = 0.068). The statistically significant two-way interaction effects of ADH7 StyI and CYP2E1 DraI on diastolic blood pressure (P = 0.029) and on the serum high density lipoprotein level (P = 0,042) were also revealed. Association of A1A2 genotype in ADHIB Msl I polymorphism with reduced amount in a serum of a very low density lipoprotein level (P = 0.045) have also been shown. This may result from multifunctional activity of alcohol metabolizing enzymes and their involvement in many metabolic and free radical reactions in the body.  相似文献   

18.
This article put the genetic association exploration of osteoprotegerin (OPG) gene polymorphisms in promoter region (A-163G, T-245G) and fracture risk first and hoped to explain the ethology of fracture. The genotyping of OPG gene polymorphisms was conducted with the method of polymerase chain reaction-restriction fragment length polymorphism in 125 fracture patients and 138 relative controls. The genotype frequencies of selected controls based on OPG gene polymorphisms were checked by the χ2 test whether conformed to Hardy–Weinberg equilibrium (HWE). The relative risk was represented with odds ratio (OR) and 95% confidence interval (95% CI) between gene polymorphism and disease. The linkage disequilibrium (LD) and haplotype were also analyzed. The genotypes distributions of selected controls in OPG polymorphisms conformed to HWE. The G allele of A-163G polymorphism carriers had the tendency to suffer from fracture in the same condition, compared with A allele carriers (OR = 1.63, 95% CI = 1.04–2.55). TG and TG/GG genotypes of OPG T-245G polymorphism also showed the increased risk of fracture development, but not TT genotype (OR = 2.22, 95% CI = 1.15–4.28; OR = 2.45, 95% CI = 1.28–4.68). Likely, the mutant allele G had an abnormally higher frequency in cases than controls (14.00% and 6.16%). These two polymorphisms existed the LD and the haplotype G -163–G -245 obviously increased the risk of fracture. OPG A-163G, T-245G polymorphisms were associated with the onset of fracture and both the independent risk factors.  相似文献   

19.
Deoxyribonuclease I gene exhibits polymorphisms, including a single nucleotide polymorphism (A2317G) and a 56 bp variable number of tandem repeat, designated as HumDN1. G2317 was regarded as an independent risk factor for Japanese myocardial infarction (MI) patients. We investigated the association between either A2317G or HumDN1 polymorphism of deoxyribonuclease I gene and MI in Han Chinese population. A2317G and HumDN1 polymorphisms in 278 MI patients and 297 unrelated controls were detected by PCR and PCR-restriction fragment length polymorphism. Plasma lipids were measured in fasting state by biochemical methods. A new HumDN1 genotype -HumDN1 4/6 was found in Han Chinese MI patients. Genotype distributions and allele frequencies of A2317G and HumDN1 did not differ between MI patients and control group (all P > 0.05). In addition, none of estimated haplotypes significantly increased or decreased the risk of MI. In analysis of covariance, plasma total cholesterol was observed to be associated with HumDN1 genotypes in MI patients (P = 0.02). Our data suggest HumDN1 genotypes are related to total cholesterol levels in Han Chinese MI patients, but deoxyribonuclease I gene polymorphisms are not associated with susceptibility to MI in Han Chinese.  相似文献   

20.
Summary A Japanese group comprising 40 hypertriglyceridaemic and 35 normolipidaemic subjects were genotyped for two intragenic DNA restriction fragment length polymorphisms (RFLPs) at the A-1 and C-III gene loci. An Sst-1 polymorphism is located at the 3 end of the C-III gene and a Msp-1 polymorphism in the third intron of the A-1 gene. The polymorphic restriction sites are 3.8kb apart. The polymorphism with Sst-1 was present at allelic frequencies of 0.67 (S1 allele) and 0.33 (S2 allele), and the polymorphism with Msp-1 was present at allelic frequencies of 0.55 (M1 allele) and 0.45 (M2 allele). The alleles S1, S2, M1, and M2 are in linkage disequilibrium and three haplotypes were identified S1-M1, S1-M2, and S2-M2. Unlike the previously reported association of the S2 allele with hypertriglyceridaemia found in Caucasians there was no difference in the frequency of S2 allele between normolipidaemic and hyperlipidaemic Japanese. However one of the haplotypes S1-M2 was significantly increased in the hypertriglyceridaemic subjects (32% versus 11% P>0.025). Thus in Japanese there is an association with genotypes at this locus and hypertriglyceridaemia but with a different haplotype than in Caucasians.  相似文献   

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