Hb F Levels in Indian Sickle Cell Patients and Association with the HBB Locus Variant rs10128556 (C>T), and the HBG XmnI (Arab-Indian) Variant.

The prevalence of sickle cell disease in India is very high. Hb F is one of the most powerful modulators of disease severity in sickle cell disease patients. It was traditionally thought that the disease is milder in Indian sickle cell disease patients predominantly due to the Arab-Indian haplotype characterized by the HBG XmnI [rs7482144 (G>A)] variant, which is associated with increased Hb F levels. In the current study, we investigated the Hb F levels in individuals with the rs10128556 (C>T) variant and also determined its linkage with the HBG XmnI variant. The present study was conducted on a cohort of 275 individuals, which consisted of 221 patients with sickle cell disease and 54 patients with sickle cell trait. Analysis of hemoglobin (Hb) fractions and variants was done on the high performance liquid chromatography (HPLC) system. Genotyping for rs10128556 was done by direct sequencing of the products. Mean Hb F levels in the sickle cell disease patients was 19.36 ± 6.79. The genotypic frequencies for rs10128556 were 82.0% (TT), 16.7% (CT) and 1.3% (CC) for sickle cell disease patients. The minor C allele resulted in 52.0% decrease in Hb F levels when homozygous and 7.0% decrease when heterozygous. The rs10128556 single nucleotide polymorphism (SNP) was in strong but not complete linkage with the HBG XmnI variant. In conclusion, the study determined for the first time the frequency and association of rs10128556 in Indian sickle cell disease patients with Hb F. It also established that it was not in complete linkage with the HBG XmnI variant in this high risk population.

Genetic variant in the BCL11A (rs1427407), but not HBS1-MYB (rs6934903) loci associate with fetal hemoglobin levels in Indian sickle cell disease patients.

India along with Nigeria and DRC contribute to 57% of the world sickle cell anemia population. The annual number of newborns in India with SCA was estimated at 44,000 in 2010. Even with this high prevalence there is minimal information about genetic factors that influence the disease course in Indian patients. The current study was conducted on 240 patients with SCD and 60 with sickle cell trait, to determine the association of genetic variants at the BCL11A (rs1427407) and HBS1-MYB (rs6934903) loci with fetal hemoglobin levels (HbF). Both these loci have been implicated with influencing HbF levels, a powerful modulator of the clinical and hematologic features of SCD. Our results indicate the BCL11A rs1427407 G>T variant to be significantly associated with HbF levels {19.12±6.61 (GG), 20.27±6.92 (GT) and 24.83±2.92 (TT) respectively} contributing to ~23% of the trait variance. Interestingly no association of the HBS1L-MYB rs6934903 with the HbF levels was seen. The present study indicates the BCL11A (rs1427407) but not HMIP (rs6934903) to be associated with elevated HbF levels in Indian patient. Further interrogation of additional variants at both the loci; as also a GWAS which may help uncover new loci controlling HbF levels.

Variant at 9p21 rs1333049 is associated with age of onset of coronary artery disease in a Western Indian population: a case control association study.

The 9p21 chromosomal region has been associated with coronary artery disease (CAD) in many genome wide association studies (GWAS). To date no information exists regarding the rs1333039 SNP which showed the strongest association in the WTCCC GWAS with CAD risk in the Indian population. The present study attempts to replicate the findings in the Indian population. Genotyping for rs1333049 was done in 229 cases and 151 controls by allele-specific real-time assay. A higher frequency of the risk allele rs1333049C was seen in cases (0·60) as compared with controls (0·49), which associated with CAD risk both in univariate (OR = 1·564, 95%CI = 1·154-2·119, P = 0·003) and multivariate analysis (OR = 2·460, 95%CI = 1·139-5·314, P = 0·022). Increased frequency of the risk allele was seen in younger individuals with CAD where 40% individuals in the age group 30-55 years had the CC genotype as compared with 29 and 24·5% in the age group 56-65 years and > 65 years, respectively (CC versus GG, P = 0·045). Higher incidence of the CC genotype was seen in MI patients, but missed significance when compared with controls (OR = 1·361, 95%CI = 0·954-1·942, P = 0·084). In conclusion, the rs1333049 variant is significantly associated with CAD risk and also with age of onset in the Western Indian population. However there are differences in the haplotype structure of this SNP with the neighbouring rs10757278 SNP, these differences emphasize the importance of genotyping all risk variants at this locus which could underlie the differences in risk susceptibility to CAD across populations.

Promoter variants in interleukin-6 and tumor necrosis factor alpha and risk of coronary artery disease in a population from Western India.

INTRODUCTION: A central component of the atherosclerotic process is inflammation. Single nucleotide polymorphisms (SNPs) present in the promoter region of various cytokines can lead to altered levels of the transcript and a state of low-grade inflammation exacerbating the risk of coronary artery disease (CAD). The present work tries to understand the role of permissive promoter variants in the interleukin-6 gene (IL-6-174G/C) and the tumor necrosis factor alpha (TNFα-308G/A) in the causation of CAD and also dyslipidemia. MATERIALS AND METHODS: Genotyping was conducted on 100 cases of CAD and 150 controls by the allele termination assay SNaPshot. Biochemical parameters were determined by routine enzymatic endpoint methods. The results were analyzed by appropriate statistical methods. RESULTS: No differences in the minor allele frequency IL-6-174G/C SNP were seen between cases and controls (0.13 vs. 0.12). The differences in the allele frequency of TNFα-308A between cases (6%) and controls (2%) have led to an odds ratio, 3.370; 95% confidence interval, 1.039-11.543; P=0.033 in the univariate analysis. In the final logistic regression analysis, however none of the variants were associated with an increased risk of CAD. CONCLUSIONS: In summary, no association of the permissive promoter variants in the IL-6 gene and the TNFα gene were seen with an increased CAD risk. These and other studies highlight the importance of doing population specific studies.

Mutations in the HD and PEST domain of Notch-1 receptor in T-cell acute lymphoblastic leukemia: report of novel mutations from Indian population.

Notch-1 is a transmembrane receptor protein that directs T-cell differentiation. Gain-of-function mutations in Notch-1 have been reported in more than 50% of human T-cell acute lymphoblastic leukemia (T-ALL). The current study was undertaken to characterize mutations in the heterodimerization (HD) domain and proline, glutamic acid, serine, threonine-rich (PEST) domain of the Notch-1 receptor. RNA was isolated from peripheral blood/bone marrow of 15 de novo T-ALL subjects; the Notch-1 HD and PEST regions were amplified and sequenced. Overall six patients (40%) had at least one Notch-1 mutation, 2/15 (13%) in the HD and 4/15 (27%) in the PEST domain. None of the samples showed simultaneous mutations in HD and PEST domains. Mutations were seen in 4/10 adult patients (40%); in the pediatric cohort 2/5 (40%) had mutations both of which were in the PEST domain. Of the different mutations, two have been previously reported and the other four are novel. A high incidence of Notch-1 mutations has been seen; unlike other studies, a higher frequency of mutations was found in PEST domain. The current study also served to identify four novel mutants that add new insights into the genetic heterogeneity of T-ALL. More ongoing larger studies are warranted to elucidate the molecular pathogenesis of T-ALL that arises in this part of the world.

Frequency of fokI and taqI polymorphism of vitamin D receptor gene in Indian population and its association with 25-hydroxyvitamin D levels.

BACKGROUND: The VDR protein is at the centre of the vitamin D endocrine system, a complex physiological system with substantial feedback regulatory mechanisms involved in maintaining serum calcium and 1, 25 dihydroxy vitamin D3. Variations in VDR gene are shown to have implications in several diseases and have also been implicated as an important genetic factor affecting bone mass. AIM: To determine the frequency of Fok I and Taq I variants in healthy Indian individuals and its association with 25-OH-Vitamin D levels. SETTINGS AND DESIGN: Blood samples were collected from 143 unrelated normal individuals (Male-84 and Female-59) and their genotypes determined. MATERIALS AND METHODS: After amplification by polymerase chain reaction, each polymorphism was genotyped by restriction fragment length polymorphism. For 100 normal healthy individuals 25-hydroxyvitamin D estimation was done using DiaSorin kit method. STATISTICAL ANALYSIS: Graph pad software was used to calculate the P values from the Chi-square. RESULTS: Out of 143 samples analyzed for FokI and TaqI polymorphisms the following genotypic frequency was obtained FF 59%, Ff 36%, ff 5% and TT 49%, Tt 43%, tt 8% respectively. CONCLUSIONS: Results indicate that the distribution of the polymorphic loci Fok I and Taq I vary considerably not only in different populations, but also within India. Furthermore, when the genotypes were analyzed with respect to 25-OH-Vitamin D levels, a significant association was seen for the Taq 1 SNP but not with the Fok I.

Reference ranges for lymphocyte subsets in adults from western India: influence of sex, age and method of enumeration.

BACKGROUND: The enumeration of absolute CD4 counts is of primary importance, since therapeutic protocols for HIV1 patients are based on these. AIMS: To establish reference ranges for the CD4 and CD8 T-lymphocytes in the Indian population. SETTINGS AND DESIGN: Enumeration of absolute numbers and percentages of lymphocyte subsets was performed in 252 healthy adult Indians. METHODS AND MATERIALS: The assays for SPT were carried out using the Beckman EPICS XL-MCL flow cytometer and the cytostat tetraCHROME reagent containing CD45/CD8/CD4/CD3 monoclonal antibodies. For comparison with DPT the absolute lymphocyte count was obtained using the Coulter STK-S fully automated hematology analyzer. STATISTICAL ANALYSIS: Regression analysis and Students t test were used for data analysis. RESULTS: Median values were as follows; absolute CD3 counts 1446 cells/mm3 (total), 1361 cells/mm3 (males) and 1511 cells/mm3 (females); absolute CD4 counts are 771 cells/mm3 (total), 705 cells/mm3 (males) and 839 cells/mm3 (females); absolute CD8 counts are 555 cells/mm3 (total), 552 cells/mm3 (males) and 561 cells/mm3 (females). The median CD4/CD8 ratio for the total samples was 1.34, for males 1.22 and for females 1.49. CONCLUSIONS: In this study we have established reference ranges for normal Indian adults using the fully automated Single Platform Technology. The lymphocyte subsets values of our population are closer to those of the population from Botswana and China rather than the Western population. The absolute CD3 and CD4 counts and the CD4:CD8 ratio are higher in females than in males. Consistently higher values are obtained by the DPT as compared to the SPT.

Frequency and association of disabled homolog 2-interacting protein (DAB2IP) variant rs7025486 G>A with coronary artery disease risk in Indian population.

Genome wide association study has identified rs7025486 G>A polymorphism within DAB2IP (Disabled homolog 2-interacting protein) gene with increased risk of coronary heart disease (CAD). In this study we have determined the frequency and association of rs7025486 with CAD in Indians. The study was performed on 214 patients with CAD and 125 controls. The 'AA' genotype was associated with an increased risk in the CAD age group <50 yrs as compared to CAD age group>50 yrs (OR 3.149; P 0.034) and controls >50 yrs (OR 3.430; P 0.080). The risk allele (A) was significantly associated with premature CAD.

Homozygous c.1160C>T (P38L) in the MECP2 gene in a female Rett syndrome patient.

Rett syndrome is a severe X-linked dominant neurodevelopmental disorder. Mutations in the MECP2 gene on chromosome Xq28 have been shown to be the cause of Rett syndrome. Sequencing of the MECP2 gene in a patient with clinical suspicion of Rett syndrome revealed c.1160C>T (P387L) in exon 4 of the MECP2 gene homozygously. Females with Rett syndrome are usually heterozygous for a mutation in MECP2. Uniparental disomy as a probable cause for the homozygous presence of this mutation was ruled out by quantitative fluorescence-polymerase chain reaction. Moreover to our knowledge this mutation has only been reported in males with X-linked mental retardation (MRX). We hypothesize that the presence of this mutation c.1160C>T (P387L) in the homozygous form is responsible for the Rett syndrome-like phenotype seen in this patient. This novel report reveals for the first time the homozygous presence of a mutation which has hitherto only been reported in males with MRX.

Genetics of fetal hemoglobin in tribal Indian patients with sickle cell anemia.

India tops the list of countries with sickle cell disease (SCD) with an estimated 44,000 live births in 2010 and a prevalence of 10%-33%. In the present study, the first from India, we have investigated the effect of genetic variants in the BCL11A, the HMIP (HBS1L-MYB intergenic polymorphism) locus, in addition to the HBB locus, which are known to be associated with fetal hemoglobin (HbF) levels, a major modulator of the disease phenotype. The present study was conducted on 240 individuals with SCD and 60 with sickle cell trait. Genotyping was performed for the BCL11A rs11886868 and rs34211119; HMIP rs9399137, rs189600565, rs7776196, rs34778774, and rs53293029; HBG2 Xmn1 polymorphism rs7482144; and -68C > T HBD promoter polymorphism. All the 3 quantitative trait loci were associated with HbF levels in Indian patients with SCD. The highest difference was seen in the Xmn1 single-nucleotide polymorphism, which accounted for 11% of the trait variance, the BCL11A rs11886868 for 3.65%, whereas the HMIP rs9399137 for 3.8%. The present study indicates the BCL11A, HMIP, and ß-globin region to be associated with increased HbF levels in Indian patient. Further interrogation of these genotypes with respect to pain crisis is warranted in this population, which may help in prognostication, as also a genome-wide association study, which may help uncover new loci controlling HbF levels.

Investigation of KIF6 Trp719Arg in a case-control study of coronary artery disease in Western Indians.

BACKGROUND: A single-nucleotide polymorphism Trp719Arg (rs20455T>C) in the kinesin-like protein 6 (KIF6), which is a protein involved in intracellular transport, has been shown to predict increased coronary artery disease (CAD) risk and event reduction during statin therapy. AIM: In the current study, we have evaluated the association of the variant Trp719Arg with CAD/non fatal myocardial infarction (MI) in Western Indians. METHODS: Genotyping for Trp719Arg was done by an allele-specific real-time assay in 227 cases with confirmed CAD and 150 controls. RESULTS: We have found that the KIF6 719 Arg carriers were not at a significantly higher risk for CAD/non-fatal MI in this case-control study of an Indo-European population from Western India (Unadjusted odds ratio [OR] 0.767 95% confidence interval [CI] 0.573-1.027 for 719Arg carriers). When the genotypes were further tested to determine association with prevalent myocardial infarction as the event versus CAD, no association was seen in a univariate analysis (MI vs. CAD OR 0.804 95% CI 0.543-1.189; MI vs. Controls OR 0.702 95% CI 0.482-1.021). CONCLUSION: In summary, carriers of the KIF6 719Arg allele were not at increased risk of CAD/non-fatal MI in a case-control study of Indians (Indo-Europeans) living in Western India.

Influence of genetic variants in the apolipoprotein A5 and C3 gene on lipids, lipoproteins, and its association with coronary artery disease in Indians.

Indians worldwide demonstrate a triad of elevated triglyceride (TG) with high low-density lipoprotein cholesterol and low high-density lipoprotein cholesterol levels. In the present study, we aim to investigate the effect of -1131T > C, -3A > G, c.56 C > G, and c.553 G > T SNPs in the apolipoprotein A5 (APOA5) gene and 1100C > T and 3238C > G in the apolipoprotein C3 (APOC3) on plasma lipid and lipoprotein levels and risk of coronary artery disease (CAD) in Indians. Genotyping and lipid assays were carried out using standard protocols in a study population that included 150 controls and 90 cases with CAD. Significant associations between minor alleles and higher TG levels were seen for -1131T > C (P < 0.001), -3A > G (P < 0.001), c.56C > G (P = 0.026), and c.553G > T (P = 0.003) SNPs in the APOA5 gene and 1100C > T (P = 0.001) and 3238C > G (P = 0.009) in the APOC3 gene. The haplotypes 11211, 22111, 11112, and 22112 were significantly associated with TG levels (P = 0.025, P = 0.017, P = 0.027, and P < 0.001, respectively) and very-low-density lipoprotein cholesterol levels (P = 0.025, P = 0.017, P < 0.001, and P = 0.002) in males. The 22111, 11112, and 22112 were associated with elevated TG (P = 0.030, P = 0.036, and P = 0.024) but not VLDL-C levels in females. No association with other lipid parameters was seen. In the logistic regression model, the rare S2 allele was a significant risk factor (P = 0.030, 95% CI 1.186-31.432) along with smoking (P < 0.0001, 95% CI 2.018-10.397) for CAD. The APOA5 and APOC3 locus is a strong determinant of plasma TG levels in Indians. The APOC3 3238G is a risk factor for CAD and a higher frequency was also seen with type 2 diabetes mellitus.

Compound heterozygosity of Hb D(Iran) (beta(22) Glu-->Gln) and beta(0)-thalassemia (619 bp-deletion) in India.

The present report describes the hematologic and molecular study of the second case of Hb D(Iran) associated with beta(0)-thalassemia (619 bp-deletion) found in India and the first case in which the mutations have been identified at molecular level. The patient showed hypochromic, microcytic red cell picture with reduced red cell indices. The characterization of the hemoglobinopathy was made by electrophoretic and chromatographic techniques and confirmed by sequencing of the beta-globin gene. Both the propositus and her father were found to be carriers of the gene for beta(0)-thalassemia owing to the 619 bp-deletion mutation as seen by the polymerase chain reaction (PCR). Single base substitution GAA > CAA (indicative of Hb D(Iran)) in the heterozygous form was seen in the propositus as well as the mother by sequencing.

Cancer-related anemia in a rat model: alpha2-macroglobulin from Yoshida sarcoma shortens erythrocyte survival.

Implantation of Yoshida ascites sarcoma in rats was found to lead to a reduction in the hemoglobin content, the erythrocyte count and the packed cell volume of blood to 30% of normal in 4 d; however, there was no decrease in the mean cell hemoglobin, the mean cell volume and the mean corpuscular hemoglobin concentration, or suppression of erythropoiesis. The red cells from the circulation of tumor-bearing animals, tagged with (51)Cr and injected intravenously in normal rats, showed significantly faster clearance than normal. The erythrocytes contaminating the tumor ascites exhibited extremely short survival, suggesting that one or more secreted tumor product(s) may be responsible for the effect. Incubation of red cells from normal rats in the cell-free ascites fluid, or with an isoform of alpha2-macroglobulin purified from it, also led to reduction in the survival; but the ascites fluid depleted specifically of alpha2-macroglobulin was without any effect. The erythrocytes exhibiting reduced survival showed a proportionate decrease in their cellular deformability. The study identifies a tumor product that is directly responsible for the causation of anemia in the host, and the mechanism by which it does so.