| 1. |
- Carlsson, Lena E, et al.
(författare)
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Platelet receptor and clotting factor polymorphisms as genetic risk factors for thromboembolic complications in heparin-induced thrombocytopenia.
- 2003
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Ingår i: Pharmacogenetics. - 0960-314X .- 1473-561X. ; 13:5, s. 253-8
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Tidskriftsartikel (refereegranskat)abstract
- Heparin-induced thrombocytopenia (HIT) is an immune mediated adverse reaction to heparin treatment often associated with limb- and/or life-threatening thromboembolic complications (TECs). Presently, no prognostic marker has been identified that allows differentiation between mildly (isolated thrombocytopenia) and severely (TECs) affected patients. This study assesses the impact of platelet glycoprotein- and clotting factor polymorphisms in HIT-patients with isolated thrombocytopenia compared to HIT-patients with TECs. Sixty-three HIT-patients with isolated thrombocytopenia and 79 HIT-patients with HIT-related TECs were genotyped for GPIIb-IIIa polymorphisms (HPA-1, HPA-3), GPIa-IIa polymorphisms (HPA-5, GPIaC807T), GPIb-IX-V polymorphisms (HPA-2, Kozak-5, VNTR), and clotting factor polymorphisms (FV-Leiden R506Q, prothrombin PT-G20210A and MTHFR C677T). Women more often presented with TECs than men (P = 0.04). No differences in genotype frequencies could be seen on comparing HIT-patients with and without TECs. Analysing men and women separately, the C allele of the Kozak polymorphism was overrepresented in men who developed TECs (P = 0.034). The enhanced risk of women to develop HIT-associated TECs remains unexplained but it is potentially important in view of recent data on sex-hormone related changes of haemostasis. There was no correlation between platelet glycoprotein- and clotting factor polymorphisms and the risk to develop HIT-associated TECs. An association between the development of TECs and the Kozak-5C allele could be seen among male patients. However, this would need to be assessed in further larger studies. Most likely, the high levels of thrombin generation during acute HIT are so procoagulant that less pronounced risk factors such as polymorphisms are overshadowed.
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| 2. |
- Liljedahl, Ulrika, et al.
(författare)
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A microarray minisequencing system for pharmacogenetic profiling of antihypertensive drug response
- 2003
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Ingår i: Pharmacogenetics. - : Ovid Technologies (Wolters Kluwer Health). - 0960-314X .- 1473-561X. ; 13:1, s. 7-17
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to develop a microarray genotyping system for multiplex analysis of a panel of single nucleotide polymorphisms (SNPs) in genes encoding proteins involved in blood pressure regulation, and to apply this system in a pilot study demonstrating its feasibility in the pharmacogenetics of hypertension. A panel of 74 SNPs in 25 genes involved in blood pressure regulation was selected from the SNP databases, and genotyped in DNA samples of 97 hypertensive patients. The patients had been randomized to double-blind treatment with either the angiotensin II type 1 receptor blocker irbesartan or the beta 1-adrenergic receptor blocker atenolol. Genotyping was performed using a microarray based DNA polymerase assisted 'minisequencing' single nucleotide primer extension assay with fluorescence detection. The observed genotypes were related to the blood pressure reduction using stepwise multiple regression analysis. The allele frequencies of the selected SNPs were determined in the Swedish population. The established microarray-based genotyping system was validated and allowed unequivocal multiplex genotyping of the panel of 74 SNPs in every patient. Almost 7200 SNP genotypes were generated in the study. Profiles of four or five SNP-genotypes that may be useful as predictors of blood pressure reduction after antihypertensive treatment were identified. Our results highlight the potential of microarray-based technology for SNP genotyping in pharmacogenetics.
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| 3. |
- Lindqvist Appell, Malin, 1976-, et al.
(författare)
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Identification of two novel sequence variants affecting thiopurine methyltransferase enzyme activity
- 2004
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Ingår i: Pharmacogenetics. - : Ovid Technologies (Wolters Kluwer Health). - 0960-314X .- 1473-561X. ; 14:4, s. 261-265
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Tidskriftsartikel (refereegranskat)abstract
- The polymorphic enzyme thiopurine methyltransferase (TPMT) is involved in the methylation of thiopurines. On comparing the phenotype with the genotype in Swedish patients with inflammatory bowel disease and healthy individuals, we found two discordant cases with low TPMT enzyme activity (0.3 and 0.4 U/ml packed red blood cells (pRBC). Genotyping by pyrosequencing revealed that they carried the nucleotide substitutions 460G>A and 719A>G, giving two possible genotypes (TPMT*1/*3A or TPMT*3B/ *3C). DNA sequencing of exon III to X was performed in the patients and their parents. We identified an A>G transition in the start codon (exon III, 1A>G, Met>Val, TPMT*14) in one of the patients and her father (6.3 U/ml pRBC). The mother in this family carried the 460G>A and 719A>G nucleotide substitutions (TPMT*3A, 5.0 U/ml pRBC). In the second family, sequencing revealed a G>A transition in the acceptor splice site in intron VII/exon VIII (IVS7 - 1G>A, TPMT*15) in the patient and his mother (6.9 U/ml pRBC). His father was genotyped as TPMT*1/*3A (6.0 U/ml pRBC). Hence, we report the identification of two novel sequence variants, present in highly conserved nucleotide positions of the human TPMT gene, resulting in a loss of enzyme activity.
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| 4. |
- Syvänen, Ann-Christine, et al.
(författare)
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Genetic polymorphism of catechol-O-methyltransferase (COMT) : correlation of genotype with individual variation of S-COMT activity and comparison of the allele frequencies in the normal population and parkinsonian patients in Finland
- 1997
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Ingår i: Pharmacogenetics. - 0960-314X .- 1473-561X. ; 7:1, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- The catechol-O-methyltransferase (COMT) gene occurs as two polymorphic alleles, which code for a high activity thermostable and low activity thermolabile form of the enzyme. We devised a fast solid-phase minisequencing assay for genotyping the COMT gene at nucleotide position 544 encoding amino acid residue 158. The method was applied to correlate the genotype of the COMT gene with the biological activity of the COMT enzyme. In red blood cells from individuals homozygous for G at nucleotide position 544 coding for Val-158, the activity of COMT ranged from 0.55-1.03 pmol min-1 mg-1 protein, and in individuals homozygous for A at position 544 coding for Met-158, the activity ranged from 0.21-0.43 pmol min-1 mg-1. Heterozygotes showed intermediate activities of 0.20-0.88 pmol min-1 mg-1. The thermostability (heated/unheated) at 48 degrees C of the high activity form was shown to be about two-fold compared to that of the low activity form of the enzyme. By analysing 76 individual samples and three pooled samples representing altogether 3140 individuals using the solid-phase minisequencing method, the two COMT alleles were shown to be equally distributed in the Finnish population. No statistically significant difference in the frequencies of the COMT alleles was found when comparing the normal population with a sample of 158 Finnish patients with Parkinson's disease.
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| 5. |
- Söderström, Torbjörn, et al.
(författare)
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5alfa-reductase 2 polymorphisms as risk factors in prostate cancer
- 2002
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Ingår i: Pharmacogenetics. - : Ovid Technologies (Wolters Kluwer Health). - 0960-314X .- 1473-561X. ; 12:4, s. 307-12
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Tidskriftsartikel (refereegranskat)abstract
- Prostate cancer is a significant cause of death in Western countries and is under the strong influence of androgens. The steroid 5alpha-reductase 2 catalyzes the metabolism of testosterone into the more potent androgen dihydrotestosterone in the prostate gland. The enzyme is a target in pharmacological treatment of benign prostatic hyperplasia using specific inhibitors such as finasteride. Makridakis et al. have characterized the V89L and A49T polymorphisms in recombinant expression systems. The L allelic variant has a lower Vmax/Km ratio than the V variant. In the A49T polymorphism, the T variant has an increased Vmax/Km ratio. We performed a population-based case-control study of the impact of the SRD5A2 V89L and A49T polymorphisms on the risk of prostate cancer. We also studied the relation between the genotypes and age at diagnosis, tumor, node, metastasis stage, differentiation grade, prostate specific antigen and heredity. The study included 175 prostate cancer patients and 159 healthy controls that were matched for age. There was an association with SRD5A2 V89L LL genotype and metastases at the time of diagnosis, OR 5.67 (95% CI 1.44-22.30) when adjusted for age, differentiation grade, T-stage and prostate specific antigen. Heterozygous prostate cancer cases that carried the SRD5A2 A49T AT genotype were significantly younger than cases that carried the AA genotype, (mean age 66 years vs 71, P = 0.038). The SRD5A2 V89L and A49T polymorphisms were, however, not associated with altered prostate cancer risk. Further studies of the V89L polymorphism may lead to better understanding of the etiology of prostate cancer metastases.
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| 6. |
- Wadelius, Mia, et al.
(författare)
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Polymorphisms in NAT2, CYP2D6, CYP2C19 and GSTP1 and their association with prostate cancer
- 1999
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Ingår i: Pharmacogenetics. - 0960-314X .- 1473-561X. ; 9:3, s. 333-40
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Tidskriftsartikel (refereegranskat)abstract
- The development of prostate cancer is dependent on heredity, androgenic influences, and exposure to environmental agents. A high intake of dietary fat is associated with an increased risk of prostate cancer, either through influence on steroid hormone profiles or through production of carcinogenic compounds that require biotransformation by enzymes. The polymorphic glutathione S-transferase (GST), N-acetyltransferase (NAT), and cytochrome P450 (CYP) enzymes are of particular interest in prostate cancer susceptibility because of their ability to metabolize both endogenous and exogenous compounds, including dietary constituents. Association between different NAT2, CYP2D6, CYP2C19 and GSTP1 genotypes and prostate cancer was studied in a Swedish and Danish case-control study comprising 850 individuals. The combined Swedish and Danish study population was analysed by polymerase chain reaction for the NAT2 alleles *4, *5A, *5B, *5C, *6 and *7, and for the CYP2D6 alleles *l, *3 and *4. The Swedish subjects were also analysed for the CYP2C19 alleles *1 and *2, and the GSTP1 alleles *A, *B and *C. No association was found between prostate cancer and polymorphisms in NAT2, CYP2D6, CYP2C19 or GSTP1. An association between CYP2D6 poor metabolism and prostate cancer was seen among smoking Danes; odds ratio 3.10 (95% confidence interval 1.07; 8.93), P = 0.03, but not among smoking Swedes; odds ratio 1.19 (95% confidence interval 0.41; 3.42), P = 0.75. Smoking is not a known risk factor for prostate cancer, and the association between CYP2D6 poor metabolism and prostate cancer in Danish smokers may have arisen by chance.
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| 7. |
- Wadelius, Mia, et al.
(författare)
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Polymorphisms of NAT2 in relation to sulphasalazine-induced agranulocytosis
- 2000
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Ingår i: Pharmacogenetics. - 0960-314X .- 1473-561X. ; 10:1, s. 35-41
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Tidskriftsartikel (refereegranskat)abstract
- Agranulocytosis is a rare, but serious adverse reaction to sulphasalazine. The polymorphic enzyme N-acetyltransferase 2 (NAT2) plays an important role in the metabolism of sulphasalazine. This study was conducted to analyse whether the risk of sulphasalazine-induced agranulocytosis is increased in slow acetylators. Patients were treated for inflammatory disease, mostly joint disease, with a mean dose of 2 g sulphasalazine daily. Thirty-nine patients reacted with agranulocytosis, while 75 patients had been treated for a minimum of 3 months without haematological side-effects. A population-based control panel of 448 individuals was used for comparison. All subjects were genotyped for NAT2 by polymerase chain reaction followed by restriction enzyme digestion. The six most common allelic variants were analysed: NAT2*4, NAT2*5A, NAT2*5B, NAT2*5C, NAT2*6 and NAT2*7. The proportion of slow acetylators was significantly higher in patients with sulphasalazine-induced agranulocytosis (69%) and population-based controls (64%) compared to patients who tolerated sulphasalazine (45%); odds ratio 2.71 [95% confidence interval (CI) 1.20; 6.15], P = 0.015, and odds ratio 2.17 (95% CI 1.32; 3.56), P = 0.002, respectively. Patients who developed agranulocytosis did not differ from population-based control subjects in the frequency of slow acetylators; odds ratio 1.25 (95% CI 0.62; 2.53), P = 0.535. The risk of agranulocytosis did not appear to be increased in slow acetylators, provided that the difference compared with sulphasalazine-treated control subjects was not due to a predominance of fast acetylators among patients with inflammatory joint disease. Instead, selection bias was suspected since more slow acetylators may have discontinued sulphasalazine therapy because of drug-intolerance.
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| 8. |
- Wadelius, Mia, et al.
(författare)
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Prostate cancer associated with CYP17 genotype
- 1999
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Ingår i: Pharmacogenetics. - 0960-314X .- 1473-561X. ; 9:5, s. 635-9
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Tidskriftsartikel (refereegranskat)abstract
- Androgens play an important role in the development of prostate cancer. Androgen regulating genes that show allelic variation may be susceptibility factors for the disease. One of these genes, CYP17, encodes the cytochrome P450c17alpha enzyme. It catalyses steroid 17alpha-hydroxylase/17,20 lyase activities at key points in testosterone biosynthesis. We investigated the association between a polymorphism in the CYP17 gene and prostate cancer in a population-based case-control study. All individuals studied were Caucasians born in Sweden, 178 were consecutive clinical prostate cancer patients, and 160 were age-matched control individuals randomly selected from the same catchment area. DNA was extracted from blood samples. A CYP17 gene fragment was amplified by polymerase chain reaction. The MspA1I restriction enzyme, which recognizes the base pair substitution, was used to identify the allelic variants CYP17A1 and CYP17A2. Significantly more men homozygous for the CYP17A1 allele were found among prostate cancer patients compared with control individuals; odds ratio 1.61 (95% confidence interval 1.02; 2.53), P = 0.04. According to a preliminary report, the CYP17A1/A1 genotype leads to higher circulating androgen levels, possibly by encoding for a more active androgen synthesizing CYP17 enzyme. Consequently, the CYP17A1/A1 genotype, which was found in a higher frequency among prostate cancer patients, may prove to be one of the important susceptibility factors for prostate cancer. If verified, this genotype is likely to convey a larger risk on a population basis, than the rare hereditary prostate cancer genes do.
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| 17. |
- Daly, AK, et al.
(författare)
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Nomenclature for human CYP2D6 alleles
- 1996
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Ingår i: Pharmacogenetics. - : Ovid Technologies (Wolters Kluwer Health). - 0960-314X. ; 6:3, s. 193-201
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Tidskriftsartikel (refereegranskat)
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| 40. |
- Wahlestedt, C
(författare)
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Array of possibilities
- 2003
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Ingår i: Pharmacogenetics. - : Ovid Technologies (Wolters Kluwer Health). - 0960-314X. ; 13:1, s. 1-1
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Tidskriftsartikel (refereegranskat)
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