Therapeutic Dosing of Acenocoumarol: Proposal of a Population Specific Pharmacogenetic Dosing Algorithm and Its Validation in North Indians

Objectives: To develop a population specific pharmacogenetic acenocoumarol dosing algorithm for north Indian patients and show its efficiency in dosage prediction. Methods: Multiple and linear stepwise regression analyses were used to include age, sex, height, weight, body surface area, smoking status, VKORC1-1639 G.A, CYP4F2 1347 G.A, CYP2C9*2,*3 and GGCX 12970 C.G polymorphisms as variables to generate dosing algorithms. The new dosing models were compared with already reported algorithms and also with the clinical data for various performance measures. Odds ratios for association of genotypes with drug sensitive and resistant groups were calculated. Results: The pharmacogenetic dosing algorithm generated by multiple regression analysis explains 41.4 % (p-value,0.001) of dosage variation. Validation of the new algorithm showed its predictive ability to be better than the already established algorithms based on similar variables. Its validity in our population is reflected by increased sensitivity, specificity, accuracy and decreased rates of over- and under- estimation in comparison to clinical data. The VKORC1-1639 G.A polymorphism was found to be strongly associated with acenocoumarol sensitivity according to recessive model. Conclusions: We have proposed an efficient north India specific pharmacogenetic acenocoumarol dosing algorithm whic

Glutathione S-transferase genotypes modify lung function decline in the general population: SAPALDIA cohort study

BACKGROUND: Understanding the environmental and genetic risk factors of accelerated lung function decline in the general population is a first step in a prevention strategy against the worldwide increasing respiratory pathology of chronic obstructive pulmonary disease (COPD). Deficiency in antioxidative and detoxifying Glutathione S-transferase (GST) gene has been associated with poorer lung function in children, smokers and patients with respiratory diseases. In the present study, we assessed whether low activity variants in GST genes are also associated with accelerated lung function decline in the general adult population. METHODS: We examined with multiple regression analysis the association of polymorphisms in GSTM1, GSTT1 and GSTP1 genes with annual decline in FEV1, FVC, and FEF(25–75 )during 11 years of follow-up in 4686 subjects of the prospective SAPALDIA cohort representative of the Swiss general population. Effect modification by smoking, gender, bronchial hyperresponisveness and age was studied. RESULTS: The associations of GST genotypes with FEV1, FVC, and FEF(25–75 )were comparable in direction, but most consistent for FEV1. GSTT1 homozygous gene deletion alone or in combination with GSTM1 homozygous gene deletion was associated with excess decline in FEV1 in men, but not women, irrespective of smoking status. The additional mean annual decline in FEV1 in men with GSTT1 and concurrent GSTM1 gene deletion was -8.3 ml/yr (95% confidence interval: -12.6 to -3.9) relative to men without these gene deletions. The GSTT1 effect on the FEV1 decline comparable to the observed difference in FEV1 decline between never and persistent smoking men. Effect modification by gender was statistically significant. CONCLUSION: Our results suggest that genetic GSTT1 deficiency is a prevalent and strong determinant of accelerated lung function decline in the male general population

Paraoxonase-1 Is Not a Major Determinant of Stent Thrombosis in a Taiwanese Population

BACKGROUND: Clopidogrel is a prodrug that undergoes in vivo bioactivation to show its antiplatelet effects. Recent studies have shown that cytochrome P450 (CYP), ATP-binding cassette transporters (ABCB1), and paraoxonase-1 (PON1) play crucial roles in clopidogrel bioactivation. Here, we aim to determine the effects of genetic polymorphisms of CYP (CYP 2C19*2, CYP 2C19*3, and CYP 2C19*17), ABCB1 (ABCB1 3435C>T, ABCB1 129T>C, and ABCB1 2677G>T/A), and PON1 (PON1 Q192R, PON1 L55M, and PON1 108C>T) on the development of stent thrombosis (ST) in patients receiving clopidogrel after percutaneous coronary intervention (PCI). METHODS AND RESULTS: We evaluated the incidence of ST (0.64%) in 4964 patients who were recruited in the CAPTAIN registry (Cardiovascular Atherosclerosis and Percutaneous TrAnsluminal INterventions). The presence of genetic polymorphisms was assessed in 20 subjects who developed ST after aspirin and clopidogrel therapy and in 40 age- and sex-matched control subjects who did not develop ST, which was documented after 9 months of angiographic follow-up. ST was acute in 5 subjects, subacute in 7, late in 7, and very late in 1. The presence of CYP 2C19*2 allele was significantly associated with ST (adjusted odds ratio [ORadj]: 4.20, 95% confidence interval [CI], 1.263-9.544; P = 0.031). However, genetic variations in PON1 and ABCB1 showed no significant association with ST. CONCLUSION: We conclude that in a Taiwanese population, PON1 Q192R genotype is not associated with ST development after PCI. However, the presence of CYP 2C19*2 allele is a risk factor for ST development after PCI

N-acetyltransferase polymorphism in patients with Behcet's disease

Objectives: The objective of our study was to investigate the possible role of human arylamine N-acetyltransferase 2 (NAT2) polymorphism in susceptibility to Behcet's disease.Methods: Eighty-five patients with Behcet's disease gave their written informed consent to participate in the study. Seven point mutations (G191A, C282T, T341C, C481T, A803G, G590A, G857A) in the NAT2 gene were analysed using polymerase chain reaction/restriction fragment length polymorphism techniques. In addition, each patient received 100 mg dapsone orally to determine their NAT2 phenotype. Dapsone and its metabolite monoacetyl-dapsone were measured in 3-h plasma samples using high-performance liquid chromatography. Subjects with an acetylation ratio (monoacetyl-dapsone/dapsone) less than 0.4 were defined as slow acetylators.Results: Of 85 patients with Behcet's disease, 54 (63.5%) were identified as genotypically slow acetylators. However, 60% (51 of 85) of patients were diagnosed as slow acetylators according to mono acetyl-dapsone/dapsone ratio. Thus, a low incidence of genotype/phenotype discrepancy (3.5%) was observed in Turkish patients with Behcet's disease. When we compared our results with previous phenotyping and genotyping studies in the Turkish population, frequencies of slow and rapid acetylators were not statistically different in patients with Behcet's disease. The frequency of the *5B allele was found to be slightly higher in patients with Behcet's disease than historic controls (44.7 vs 35.6%, P=0.039). However, there was no significant difference in the frequency of the overall genotypes and alleles of NAT2 between patients and controls.Conclusion: Although the frequency of the NAT2*5B allele, responsible for slow acetylation, was slightly higher in patients than historic controls, our results failed to show an association between NAT2-acetylator status and risk for developing Behget's disease

N-acetyltransferase polymorphism in patients with Behcet's disease

Objectives: The objective of our study was to investigate the possible role of human arylamine N-acetyltransferase 2 (NAT2) polymorphism in susceptibility to Behcet's disease

polymorphism and olanzapine induced weight gain

Objective: Antipsychotic induced weight gain is a major problem for second generation antipsychotics which may lead to diabetes and metabolic syndrome. Recent studies were mentioning that genetic factors might be relevant in antipsychotic induced weight gain. Aim of this study is evaluation of the association between IRS-1 Glyp972Arg polymorphism and olanzapine induced weight gain. Methods: Total of 95 patients whom were diagnosed as schizophrenia by DSM-IV criteria were included to study. Body weight, body mass index and blood glucose levels of all patients were checked at the beginning and six weeks after olanzapine treatment. Blood for DNA analysis were obtained from patients and analyzed as mentioned in literature. Data were evaluated with descriptive methods and Mann Whitney U test was used for comparison of two groups. Results: Eighty and four of patients had Glycine/Glycine and 11 patients had Glycine/Arginine genotype of IRS-1 Gly972Arg polymorphism. Despite the patients with Glycine/Glycine polymorphism gained more weight than patients with Glycine/Arginine polymorphism, the difference between Glycine/Glycine and Glycine/Arginine groups for weight change and body mass index change wasn't statistically significant. Conclusion: Our results showed no statistical relationship between the IRS-1 Gly972Arg polymorphism and olanzapine induced weight gain. However exploration of the other IRS genotypes and the antipsychotic-induced body weight change may help in the understanding of the mechanisms of antipsychotic-induced body weight gain. (Anatolian Journal of Psychiatry 2010; 11:18-22