Roumi Deb

Variability in CYP2C9 allele frequency: A pilot study of its predicted impact on warfarin response among healthy South and North Indians

BACKGROUND Wide variability exists in the frequency of pharmacogeneticmarkers for anticoagulant response in different populations. There is insufficient data on the prevalence of these variant genotypes in the Indian population. This study aims to determine the frequency of various genotype combinations of CYP2C9*2, *3 and VKORC1-1639G>A polymorphisms in the South and North Indians. METHODS Genotyping was carried out by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) technique in 209 North Indians (NI) and 82 South Indians (SI). Warfarin maintenance dose was predicted for all subjects based on FDA approved genotype-based dose estimates from revised COUMADIN medication guide. Fisher exact test and Χ2 test were applied to compare categorical data among the SI and NI groups. RESULTS In SI and NI, the allele frequency of CYP2C9*2 was 0.006 and 0.05 (significant variation; p<0.001); of CYP2C9*3 was 0.09 and 0.11; and of VKORC1-1639A was 0.14 and 0.19 (not significant), respectively. The variation in the frequency of combined CYP2C9/ VKORC1 genotypes revealed plausible difference in warfarin response among SI and NI. Based on the FDA approved revised dosing guidelines, significantly higher percentage of NI were likely to require intermediate dose (3-4 mg/day; p=0.015, RR=2.16) and were also predicted to have an increased risk of bleeding episodes and over anticoagulation (p=0.012, RR=1.93). CONCLUSIONS Genotype frequency of CYP2C9 and VKORC1 SNPs is variable among the two ethno-geographically distinct Indian populations. This could translate into diverse warfarin response among the Indian population.

Folate supplementation, MTHFR gene polymorphism and neural tube defects: a community based case control study in North India

The present study analyses the potential role of MTHFR gene polymorphism, folate supplementation and dietary pattern among the mothers of NTD neonates and controls in heterogeneous populations of North India, with the special focus on their ethnic labels. Results indicated significant increased risk for neural tube defects with respect to low folic acid supplementation and vegetarian diet in univariate and multivariate analyses. There was no significant difference in the genotypic or allelic distribution of MTHFR C677T polymorphism, however, high frequency of CT genotype, as observed, among controls suggests heterozygous advantage probably due to supplementary folate. Among the two communities, Muslim NTD mothers had higher TT genotype showing increased risk for neural tube defects (adjusted OR: 12.9; 95% CI: 1.21–136.8) and lower folic acid supplementation (adjusted OR: 3.5; 95% CI: 1.18–10.22). Whereas, marginal increased risk for NTDs with vegetarian diet was observed among Hindus. Cultural and ethnic variation in the risk factors for neural tube defects is highlighted in the study.

Knowledge, Attitude and Practices Related to Family Planning Methods among the Khasi Tribes of East Khasi hills Meghalaya

Abstract The present study was undertaken to know the extent of awareness, attitude and practices of family planning method among 1560 ever-married Khasi women aged 15-49 years from all the seven blocks of East Khasi Hills. Among Khasi women the knowledge of family planning methods is not much widespread, more than fifty percent of the women were adopting any family planning method. Majority of the women who were adopting any family planning method belonged to age group 25-35 years. However, there is a gap between the knowledge and the practice of contraception among these women.

CYP2C9, VKORC1, CYP4F2, ABCB1 and F5 variants: influence on quality of long-term anticoagulation.

AIMS The study aims to evaluate the impact of genetic, demographic and clinical data on various measures of outcome of anticoagulation quality in patients. PATIENTS AND METHODS The study consisted of 310 patients receiving long-term oral anticoagulation therapy in our hospital. Apart from demographic and clinical variables, 21 SNPs (in 7 genes) were analyzed and compared with the outcomes of anticoagulation therapy. Various outcomes that were measured are; supra therapeutic INRs (INR >3, >6), anticoagulation stabilization, time taken to stabilize and proportion of INRs within (2-3), above (>3) and below (<2) therapeutic range. RESULTS Supra therapeutic INRs were influenced by CYP2C9*2, *3, CYP4F2 rs2108622, VKORC1-1639G>A, 1173C>T, rs55894764 along with concomitant drugs, smoking, body weight and height. Persistently fluctuating INRs/absolute instability correlated with VKORC1-1639G>A, gender, height and body mass index. The time taken to stabilize was associated with CYP4F2 rs2108622, CYP2C9*14, smoking, clinical indication and concomitant drugs. The overall distribution of INR was influenced by variants in CYP4F2 rs2108622, CYP2C9*3, rs9332230, VKORC1 1173C>T, -1639G>A, rs55894764, ABCB1 rs2032582, rs1128503, rs1045642 and F5 rs6025, age, smoking and concomitant drugs. CONCLUSIONS Knowledge of factors influencing the quality of long term anticoagulation can help clinicians to customize therapy either by dose variation, therapy with alternate choice of drug, concurrent heparin therapy and/or frequent INR monitoring.

Implication of novel CYP2C9*57 (p.Asn204His) variant in coumarin hypersensitivity

INTRODUCTION Polymorphisms in CYP2C9 can vary the rate of metabolic clearance of oral anticoagulants, risking toxicity in patients. The present study focused on exploring the genetic etiology of idiopathic hyper sensitivity to coumarin anticoagulants in a patient who presented with multiple bleeding episodes and supra-elevated International Normalized Ratios. MATERIALS AND METHODS Bidirectional gene sequencing of CYP2C9 and VKORC1 was carried out. Using allele-specific polymerase chain reaction, the identified novel variant was genotyped in 309 patients on anticoagulation therapy. The pharmacoproteomic significance of the novel genetic variant was elucidated by structural demonstration of binding of coumarin molecules within the mutant CYP2C9 204His protein model and in silico bioinformatic evolutionary analyses. Three-dimensional structure model of the mutant protein was constructed on the basis of the published X-ray crystal structure of human CYP2C9 protein (Protein Data Bank, 1R9O). RESULTS The patient was identified to have a novel heterozygous missense mutation in exon 4 of CYP2C9 gene (g.9172A > C; p.Asn204His; CYP2C9*57). The variant was absent in the 309 genotyped patients. In silico bioinformatic analyses indicated the variant to have a deleterious effect on the protein. Analysis of 3D structure model of the mutant protein revealed that the substituted His204 led to restricted binding of the coumarin drug within the binding site of CYP2C9 enzyme, thereby inhibiting its metabolic clearance and thus explaining the enhanced pharmacologic effect and bleeding in the patient. CONCLUSIONS The study elucidates the structurally deleterious role of the novel CYP2C9*57 missense mutation in coumarin toxicity.

Variation in the Age at Menarche of the Assamese and Bengali Girls of Guwahati, Assam

Abstract Data on age at menarche have been collected using status quo method among 230 Assamese girls and 223 Bengali girls of Guwahati (Assam) attending School. The median age, estimated by probits, is 12.45 ± 0.02 year among Assamese girls and 12.25 ± 0.03 year among the Bengali girls, respectively. However the difference (t=6.49) is found to be statistically significant (P<0.0l). Age at menarche in relation with food habit, housing facilities and games were taken into consideration. However, the interpretation of these associations cannot be recognized as a cause and effect relationship, since these are secondary factors that are more or less associated with those factors that presumably have a more direct influence, such as nutritional status and health status etc.

Pharmacogenetic typing for oral anti-coagulant response among factor V Leiden mutation carriers

CONTEXT Factor V Leiden mutation is the most common inherited predisposition for hypercoagulability and thereby a common genetic cause for initiation of oral anti-coagulation therapy. There is a dearth of knowledge of coumarin response profile in such thrombophilic population. AIMS The current pilot study aims to estimate coumarin sensitivity in an Indian cohort with an inherited thrombophilia risk factor (Factor V Leiden mutation carriers) based on the observed frequency of CYP2C9 (*)2, (*)3 and VKORC1-1639G >A genotype combinations. SETTINGS AND DESIGN A retrospective study carried out in a tertiary health care center in India. MATERIALS AND METHODS Carriers of FVL mutation were genotyped for CYP2C9 ((*)2, F(*)3) and VKORC1 (-1639G >A) variants by PCR-RFLP technique. STATISTICAL ANALYSIS USED Chi-square test to analyze difference in expected and observed genotype frequency. RESULTS Sixty-one (n = 61) unrelated carriers of FVL mutation were observed in the 13 years study period. The allele frequency of CYP2C9 (*)2, CYP2C9 (*)3, and VKORC1-1639A in this cohort was 0.06, 0.11, and 0.16, respectively. Six (9.7%) individuals had two of the three variant alleles (heterozygous or homozygous), and 28 (45.9%) were heterozygous for at least one polymorphism. CONCLUSIONS Pre-prescription genotyping for coumarin drugs, if introduced in Indians with inherited thrombophilia (in whom oral anti-coagulant therapy may be necessary), is likely to identify 9.7% (hypersensitive) subjects in whom the optimum anti-coagulation may be achieved with reduced dosages, 44.3% (normal sensitivity) who may require higher dose and also 55.6% (hyper and moderate sensitivity) subjects who are likely to experience bleeding episodes.

Genetic Bleeding Risk Score (GBRS) for Patients on Oral Anticoagulant Therapy

Aims: The present study focussed on deriving and validating a ‘genetic bleeding risk score’ (GBRS) based on genetic and non-genetic factors associated with bleeding in patients on long term anticoagulation therapy. Patients and Methods: Patients on warfarin (n=53) or acenocoumarol (n=257) long-term therapy were genotyped for twenty one SNPs in six genes. Two GBRSs were developed and validated. Results: The incidence rate was 16.86 and 4.46 per 100 person-years for minor and major bleeding respectively. The novel GBRS (positive predictive value = 83.3%, specificity = 97.4%) comprised of four parameters; age >65 years, F5 rs6025, VKORC1 rs9934438 and CYP2C9 rs1057911. Conclusions: The present study is the first to devise and validate a genetic based score for predicting bleeding among first time users of oral anticoagulants.

Association of sociodemographic and nutritional factors with risk of neural tube defects in the North Indian population: a case-control study.

OBJECTIVE To assess the role of sociodemographic and nutritional factors in the incidence of births affected by neural tube defects (NTD) in the North Indian population. DESIGN Case-control study. SETTING Government hospitals of Delhi, India. SUBJECTS Subjects comprised 284 mothers of NTD children (cases) and 568 mothers of healthy children (controls). RESULTS Significant differences were found between case and control mothers with respect to maternal age (P = 0·005), type of drinking water (P = 0·03) and consumption of milk (P = 0·01). Univariate and multivariate analysis suggested an association of unpasteurized milk use, low consumption of vegetables, low consumption of fruits and vegetarian dietary habits with NTD births. Further, variation in the risk factors for upper and lower NTD types was also observed, pointing towards phenotypic heterogeneity in the aetiology. CONCLUSIONS The results of the present study suggest an increased risk of NTD infants in mothers with low consumption of vegetables, fruits and milk and having vegetarian dietary habits. So, in order to reduce these devastating birth defects in future offspring, better nutritional care should be provided to mothers by suggesting dietary modifications and augmenting additional micronutrient supplementation during the periconceptional period.

Effect of maternal Tp53 gene G412C polymorphism on neural tube defects: A study from North India.

CONTEXT: Tumor protein 53 (tp53) is one of the candidate gene proposed for neural tube defects, which affects central nervous system during early embryonic development, on the basis of mouse models. AIMS: The present study is an attempt to unfold the possible role of tp53 G412C polymorphism in the incidence of neural tube defect (NTDs) in humans. SETTINGS AND DESIGN: Case-control study was carried out in government hospitals of Delhi, India. MATERIALS AND METHODS: Subjects comprised of 100 mothers of NTD children and 100 matched control mothers. Information on some environmental exposures was collected along with blood samples. After DNA extraction, the genotyping of tp53 G412C polymorphism was carried out by PCR-RFLP method. Statistical Analysys: Fisher Exact or Chi square test, binary logistic model, and odds ratio (95% confidence interval) calculations were used to evaluate effect of risk factors on NTDs using SPSS v17.0. RESULTS: The ‘CC’ genotype of tp53 G412C showed protective effect towards the development of anencephaly and/or encephalocele (OR: 0.44; 95% CI: 0.19-1.00); however, no significant difference among overall NTD cases and controls was observed (P>0.05). Further segregation of all subjects based on 2 different communities, Hindus and Muslims, the association of ‘CC’ genotype of the polymorphism with reduced NTD risk was observed among Hindu community (OR: 0.33; 95% CI: 0.13-0.79). CONCLUSION: The study highlights the selective advantage provided by maternal ‘CC’ genotype, thereby reducing risk of cephalic NTDs, probably due to the lower apoptotic activity of the protein, however, more specifically in the presence of community-specific microenvironment.