👤 Ramesh Kumar Chandak

Risk estimation tools have been developed to predict coronary heart disease (CHD) in type 2 diabetes (T2D). To evaluate augmentation following the addition of lipoprotein(a) [Lp(a)] to risk calculation, we performed a pilot study. A total of 90 successive T2D patients were included. Details of clinical and biochemical features were obtained. Lp(a) was determined using ELISA. CHD risk estimation was performed using Framingham, QRISK-3, SCORE-2D, INTERHEART, and European Atherosclerosis Society (EAS) algorithms with and without Lp(a). Descriptive statistics are reported. Mean age of patients was 55.0 ± 8 years, BP systolic/diastolic 133.7 ± 12/95.0 ± 9 mm Hg, body mass index (BMI) 26.0 ± 1.9 kg/m Substantial variation in coronary artery disease (CAD) risk prediction using various clinical algorithms is observed in T2D. The EAS algorithm provides the most robust estimate. The addition of Lp(a) to the risk algorithms augments risk stratification significantly. The results of this pilot study need confirmation with larger prospective studies. Show less

Obesity is among the leading public health threats globally. Over the last few years, visceral adiposity index (VAI), and body adiposity index (BAI), derived from anthropometric, and biochemical measures, have gained importance as a measure of obesity. However, unlike other common indices like body mass index, and waist circumference, the genetic predisposition of VAI, and BAI under-examined. 2265 sib-pairs from Indian Migration Study were used for examining the association of genetic variants from the Cardio-Metabochip array with VAI, and BAI. Mixed linear regression models were run, and all inferences were based on the within-sib component of the Fulker's association models. Gene-environment/lifestyle interaction analyses were also undertaken. rs6659428 at LOC400796 | SEC16B (β = 0.26, SE = 0.05), and rs7611535 at DRD3 | LOC645180 (β = 0.18, SE = 0.04) were associated with VAI at suggestive significance value of <8.21 × 10 We report three novel genetic loci for VAI, and BAI in Indians that are important indicators of adiposity. These findings need to be replicated and validated with larger samples from different ethnicities. Further, functional studies for understanding the biological mechanisms of these adiposity indices need to be undertaken to understand the underlying pathophysiology. Show less

Recent genome-wide association studies have identified many single nucleotide polymorphisms (SNPs) associated with body mass index (BMI)/generalized obesity. In this study, we aimed to examine the associations of identified SNPs with risk of central obesity in a child population from China. We genotyped 11 SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397, BDNF rs6265, FAIM2 rs7138803, NPC1 rs1805081, SEC16B rs10913469, SH2B1 rs4788102, PCSK1rs6235, KCTD15 rs29941, BAT2 rs2844479) in the Chinese children (N = 3502, age range 6-18 years) from the Beijing Child and Adolescent Metabolic Syndrome (BCAMS). Based on the age- and sex- specific waist circumference (WC) standards generated in the BCAMS study, 1196 central obese cases and 2306 controls were identified. Of 11 studied SNPs, four SNPs and genetic risk score (GRS) based on them were statistically significantly associated with central obesity by WC criteria (FTO rs9939609: OR = 1.29, 95%CI = 1.10-1.50, p = 0.001; MC4R rs17782313: OR = 1.27, 95%CI = 1.12-1.44, p = 1.32×10⁻⁴; GNPDA2 rs10938397: OR = 1.22, 95%CI = 1.09-1.37, p = 4.09×10⁻⁴; BDNF rs6265: OR = 1.20, 95%CI = 1.08-1.34, p = 8.86×10⁻⁴; GRS: OR = 1.25, 95%CI 1.16-1.34, p = 2.58×10⁻⁹) after adjustment for sex, age, pubertal stage, physical activity and family history of obesity. Similar observations were made using weight-to-height ratio (WHtR) criterion. However, other SNPs were not associated with central obesity by WC as well as WHtR criterion. Our study replicates the statistically significant association of four SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397, BDNF rs6265) with risk of central obesity in the Chinese children. Show less

Genome wide association studies (GWAS), mostly in Europeans have identified several common variants as associated with key lipid traits. Replication of these genetic effects in South Asian populations is important since it would suggest wider relevance for these findings. Given the rising prevalence of metabolic disorders and heart disease in the Indian sub-continent, these studies could be of future clinical relevance. We studied seven common variants associated with a variety of lipid traits in previous GWASs. The study sample comprised of 3178 sib-pairs recruited as participants for the Indian Migration Study (IMS). Associations with various lipid parameters and quantitative traits were analyzed using the Fulker genetic association model. We replicated five of the 7 main effect associations with p-values ranging from 0.03 to 1.97x10(-7). We identified particularly strong association signals at rs662799 in APOA5 (beta=0.18 s.d, p=1.97 x 10(-7)), rs10503669 in LPL (beta =-0.18 s.d, p=1.0 x 10(-4)) and rs780094 in GCKR (beta=0.11 s.d, p=0.001) loci in relation to triglycerides. In addition, the GCKR variant was also associated with total cholesterol (beta=0.11 s.d, p=3.9x10(-4)). We also replicated the association of rs562338 in APOB (p=0.03) and rs4775041 in LIPC (p=0.007) with LDL-cholesterol and HDL-cholesterol respectively. We report associations of five loci with various lipid traits with the effect size consistent with the same reported in Europeans. These results indicate an overlap of genetic effects pertaining to lipid traits across the European and Indian populations. Show less

Triglycerides is an independent risk factor for coronary artery disease (CAD) and is especially important in Indians because of high prevalence of hypertriglyceridemia in this population. Both genetic and environmental factors determine triglyceride levels. In a birth cohort from India, hypertriglyceridemia was found in 41% of men and 11% of women. Subjects who had high triglycerides had more rapid body mass index (BMI) or weight gain than rest of the cohort throughout infancy, childhood and adolescence. We analysed polymorphisms in APOA5, hepatic lipase and PPARγ genes and investigated their association with birth weight and serial changes in BMI. Polymorphisms in APOA5 (-1131T > C, S19W), PPARγ (Pro12Ala) and hepatic lipase (-514C > T) were studied by polymerase chain reaction (PCR) followed by restriction digestion in 1492 subjects from the New Delhi Birth Cohort (NDBC). We assessed whether these polymorphisms influence lipid and other variables and serial changes in BMI, both individually and together.The risk allele of APOA5 (-1131C) resulted in 23.6 mg/dl higher triglycerides as compared to normal allele (P < 0.001). Risk allele of HL (-514T) was associated with significantly higher HDL2 levels (P = 0.002). Except for the marginal association of PPARγ Pro12Ala variation with a lower conditional weight at 6 months, (P = 0.020) and APOA5 S19W with a higher conditional BMI at 11 yrs of age (P = 0.030), none of the other associations between the gene polymorphisms and serial changes in body mass index from birth to young adulthood were significant. The promoter polymorphism in APOA5 was associated with raised serum triglycerides and that of HL with raised HDL2 levels. None of the polymorphisms had any significant relationship with birth weight or serial changes in anthropometry from birth to adulthood in this cohort. Show less

Type 2 diabetes mellitus (T2DM) is a major cause of coronary artery disease (CAD) and is responsible for a great deal of morbidity and mortality in Asian Indians. Several gene polymorphisms have been associated with CAD and T2DM in different ethnic groups. This study will give an insight about the association of two selected candidate gene polymorphisms; paraoxonase1 (PON1) Q192R and apolipoprotein A5 (APOA5) -1131T>C were assessed in a cohort of South Indian patients having CAD with and without T2DM. Polymerase chain reaction-based genotyping of PON1 Q192R (rs662) and APOA5-1131T>C (rs662799) polymorphism was carried out in 520 individuals, including 250 CAD patients (160 with T2DM and 90 without T2DM), 150 T2DM patients with no identified CAD, and 120 normal healthy sex- and age-matched individuals as controls. The PON1 192RR genotype and R allele frequency were elevated in both CAD and T2DM patients when compared with controls; however, only CAD patients with T2DM showed a statistical significance (p=0.023; OR=1.49; 95% CI: 1.04-2.12) when compared with controls. The APOA5-1131CC genotype and C allele also showed a significant association between the CAD+T2DM patients when compared with CAD without T2DM and healthy controls (p=0.012; OR=1.71; 95% CI: 1.0-2.67). An additive interaction between the PON1 RR and APOA5 TC genotypes was identified between the T2DM and CAD patients (p=0.028 and 0.0382, respectively). PON1 and APOA5 polymorphisms may serve as biomarkers in the South Indian population to identify T2DM patients who are at risk of developing CAD. Show less

The APOA5 gene variants, -1131T>C and S19W, are associated with altered triglyceride concentrations in studies of subjects of Caucasian and East Asian descent. There are few studies of these variants in South Asians. We investigated whether the two APOA5 variants also show similar association with various lipid parameters in Indian population as in the UK white subjects. We genotyped 557 Indian adults from Pune, India, and 237 UK white adults for -1131T>C and S19W variants in the APOA5 gene, compared their allelic and genotype frequency and determined their association with fasting serum triglycerides, total cholesterol, HDL and LDL cholesterol levels using univariate general linear analysis. APOC3 SstI polymorphism was also analyzed in 175 Pune Indian subjects for analysis of linkage disequilibrium with the APOA5 variants. The APOA5 -1131C allele was more prevalent in Indians from Pune (Pune Indians) compared to UK white subjects (allele frequency 20% vs. 4%, p = 0.00001), whereas the 19W allele was less prevalent (3% vs. 6% p = 0.0015). Patterns of linkage disequilibrium between the two variants were similar between the two populations and confirmed that they occur on two different haplotypes. In Pune Indians, the presence of -1131C allele and the 19W allele was associated with a 19% and 15% increase respectively in triglyceride concentrations although only -1131C was significant (p = 0.0003). This effect size was similar to that seen in the UK white subjects. Analysis of the APOC3 SstI polymorphism in 175 Pune Indian subjects showed that this variant is not in appreciable linkage disequilibrium with the APOA5 -1131T>C variant (r2 = 0.07). This is the first study to look at the role of APOA5 in Asian Indian subjects that reside in India. The -1131C allele is more prevalent and the 19W allele is less prevalent in Pune Indians compared to UK Caucasians. We confirm that the APOA5 variants are associated with triglyceride levels independent of ethnicity and that this association is similar in magnitude in Asian Indians and Caucasians. The -1131C allele is present in 36% of the Pune Indian population making it a powerful marker for looking at the role of elevated triglycerides in important conditions such as pancreatitis, diabetes and coronary heart disease. Show less

Apolipoprotein AV (ApoAV) gene variant, -1131T>C, is associated with increased triglyceride concentrations in all ethnic groups studied. An MseI based RFLP analysis is the most commonly used method for genotyping this SNP. We genotyped a large cohort comprising 1185 Asian Indians and 173 UK Caucasians for -1131T>C using an ARMS-PCR based tetra-primer method. For quality control, we re-genotyped approximately 10% random samples from this cohort utilizing the MseI RFLP, which showed a 2.9% (3/102) genotyping error rate between the two methods. To investigate further, we sequenced the 900 bp region around the -1131T>C polymorphism in 25 Asian Indians and 15 UK Caucasians and found a number of polymorphisms including the -987C>T polymorphism. Further analysis of the -987C>T SNP showed a higher rare allele frequency of 0.23 in Asian Indians (n = 158) compared to 0.09 in the UK Caucasians (n = 157). This SNP is located 4 bp from the 3' end of the RFLP forward primer and is in weak linkage disequilibrium with -1131T>C variant (r2 = 0.084 and D' = 1). Repeated RFLP analysis of seven subjects heterozygous for -987C>T (seven times), showed discordant results with the sequence at -1131T>C SNP nearly one third (15/49) of the time. We conclude that presence of -987C>T polymorphism in the forward primer of the MseI RFLP assay may lead to allelic drop-out and generate unforeseen errors in genotyping the -1131T>C polymorphism. Our results also emphasise the need for careful quality control in all molecular genetic studies, particularly while transferring genotyping methods between various ethnic groups. Show less