Linda Koshy

Publications

• 3.54

  Impact points

  Risk factors for aneurysmal subarachnoid hemorrhage in an Indian population.

  Linda Koshy, H V Easwer, S Premkumar, Jacob P Alapatt, A Marthanda Pillai, Suresh Nair, R N Bhattacharya, Moinak Banerjee

  Cerebrovascular diseases (Basel, Switzerland). 02/2010; 29(3):268-74.

  Aneurysmal subarachnoid hemorrhage (aSAH) has a mortality rate as high as 50%. The prevalence of intracranial aneurysms from various parts of India varies from 0.75 to 10.3%, with higher numbers of cases being diagnosed due to the increasing age of the population and improvements in imaging techniqu... [more] Aneurysmal subarachnoid hemorrhage (aSAH) has a mortality rate as high as 50%. The prevalence of intracranial aneurysms from various parts of India varies from 0.75 to 10.3%, with higher numbers of cases being diagnosed due to the increasing age of the population and improvements in imaging techniques. However, little is known about the attributable risk factors of aSAH in the Indian population. Using a case-control study we estimated the risk of factors such as hypertension, cigarette smoking, alcohol consumption, diabetes mellitus and family history of aSAH in a South Indian population. The population-attributable risk (PAR) of smoking, hypertension and alcohol use was estimated for the South Indian as well as for the general Indian population. Our results showed that cigarette smoking (OR, 3.59; p < 0.001) and a history of hypertension (OR, 2.98; p < 0.001) were significant risk factors associated with aSAH. When patients were classified by gender, it was observed that being a smoker and having hypertension increased the risk for aSAH by nearly fourfold in men. Among women, hypertension and older age were significant risk factors. The PAR estimates indicated that smoking (OR, 3.59; 95% CI, 2.13-6.06) and hypertension (OR, 2.98; 95% CI, 1.73-5.12) are significant risk factors. Hypertension and smoking may be causal risk factors which might also modify the effect of genetic factors that could increase susceptibility to aSAH in the Indian population. Since these risk factors are amenable to effective modification, our findings will be useful for a gender-specific management of aSAH.
• 2.03

  Impact points

  Role of endothelial nitric oxide synthase gene polymorphisms in predicting aneurysmal subarachnoid hemorrhage in South Indian patients.

  Linda Koshy, H V Easwer, N V Neetha, Chandrasekhar Natarajan, R N Bhattacharya, Moinak Banerjee

  Disease markers. 02/2008; 24(6):333-9.

  Endothelial nitric oxide synthase (eNOS) gene polymorphisms have been implicated as predisposing genetic factors that can predict aneurysmal subarachnoid hemorrhage (aSAH), but with controversial results from different populations. Using a case-control study design, we tested the hypothesis whether ... [more] Endothelial nitric oxide synthase (eNOS) gene polymorphisms have been implicated as predisposing genetic factors that can predict aneurysmal subarachnoid hemorrhage (aSAH), but with controversial results from different populations. Using a case-control study design, we tested the hypothesis whether variants in eNOS gene can increase risk of aSAH among South Indian patients, either independently, or by interacting with other risk factors of the disease. We enrolled 122 patients, along with 224 ethnically matched controls. We screened the intron-4 27-bp VNTR, the promoter T-786C and the exon-7 G894T SNPs in the eNOS gene. We found marked interethnic differences in the genotype distribution of eNOS variants when comparing the South Indian population with the reported frequencies from Caucasian and Japanese populations. Genotype distributions in control and patient populations were found to be in Hardy-Weinberg equilibrium. In patients, the allele, genotype and estimated haplotype frequencies did not differ significantly from the controls. Multiple logistic regression indicated hypertension and smoking as risk factors for the disease, however the risk alleles did not have any interaction with these risk factors. Although the eNOS polymorphisms were not found to be a likely risk factor for aSAH, the role of factors such as ethnicity, gender, smoking and hypertension should be evaluated cautiously to understand the genotype to phenotype conversion.

• Association of dopamine receptor polymorphisms with schizophrenia and antipsychotic response in a South Indian population

  Neetha Vijayan, Sujatha Bhaskaran, Linda Koshy, Chandrasekhar Natarajan, Lekshmy Srinivas, Chandrasekharan Nair, Priya Allencherry, Moinak Banerjee

  Behavioral and Brain Functions. 01/2007;

  Abstract Background Alterations in the dopamine transmission and receptor density are hypothesized in the pathophysiology of schizophrenia but ethnic disparities are reported to exist in disease association and therapeutic response to psychotropic medication. Antipsychotics have higher binding aff... [more] Abstract Background Alterations in the dopamine transmission and receptor density are hypothesized in the pathophysiology of schizophrenia but ethnic disparities are reported to exist in disease association and therapeutic response to psychotropic medication. Antipsychotics have higher binding affinity to D2 subtype of dopamine receptor. DRD2 Cys311, TaqIB1 and TaqIA1 variants are considered to have either reduced affinity for dopamine and hypo-dopaminergic activity. Methods We examined the role of Taq1B, Taq1D, S311C, H313H and Taq1A polymorphisms of DRD2 gene in schizophrenia and antipsychotic treatment response in 213 patients and 196 controls from a homogenous South Indian population. A more detailed genotype phenotype association analysis was carried out to understand the disease in terms of its socio-cultural factors. Results H313HTT genotype was found to be associated with schizophrenia (P = 0.004) while TaqIB1B1 genotype was significantly associated with higher psychopathology score. When treatment response was considered H313HCC, TaqIA2A2 and Taq1D1D1 had higher mean improvement scores. TaqID1D1 and H313HTT genotype were found to be significantly higher in responders than in nonresponder group. Distinct shift in the LD patterns of responder and non-responder group was observed. Certain symptoms were characteristic of our patient population. Following medication the scores and presentation of these symptoms tend to vary in the responder and non-responder groups. Conclusion Based on genotype phenotype correlations it can be suggested that certain polymorphisms can be defined for their critical functions in disease and their role in treatment response in South Indian population. The present study suggests that in addition to ethnic bias, socio-cultural factors should also be considered while evaluating genotype phenotype correlations, in association and treatment response to complex disorders like schizophrenia.

• Lack of association of Endoglin insertion polymorphism in intracranial aneurysm in South Indian population

  Linda Koshy, H Easwer, R Bhattacharya, Moinak Banerjee

  Indian Journal of Human Genetics. 01/2006;

  Background : Endoglin , is a component of transforming growth factor-β complex. It is involved in vascular development and structural maintenance of the vessel wall. Conflicting reports on the association of a six base insertion polymorphism in intron 7 of the endoglin gene in intracranial aneurysms... [more] Background : Endoglin , is a component of transforming growth factor-β complex. It is involved in vascular development and structural maintenance of the vessel wall. Conflicting reports on the association of a six base insertion polymorphism in intron 7 of the endoglin gene in intracranial aneurysms (IA) have been reported earlier. materials and Methods: A case-control study was designed to compare 102 South Indian patients with intracranial saccular aneurysms and 118 ethnically and geographically matched healthy controls. The frequency of the six base insertion polymorphism was assessed by heteroduplex analysis followed by direct sequencing. Results: Insertion allele count was 39 (19.1%) of 204 alleles in the patient group and 42 (17.8%) of 236 alleles in the control group. The INS allele frequency was similar to the frequency in Caucasian population, but it was significantly lower than the Japanese population ( P =0.01). There was also no relationship of this polymorphism in patients with single aneurysm (33/176 alleles) or those with multiple aneurysms (6/28 alleles). Conclusion: Six base insertion polymorphism in Endoglin gene was not found to be a risk factor for intracranial saccular aneurysms in the South Indian population. Ethnic-related differences were observed. This is the first report on any genetic mutation in intracranial aneurysms in Indian population.