Wide spectrum of novel and rare hemoglobin variants in the multi-ethnic Indian population: A review.

The hemoglobin (Hb) variants are qualitative abnormalities due to production of structurally abnormal globin proteins. They are categorized based on the type of mutation present in the α1, α2, ß, Gγ, Aγ and δ globin genes. So far, more than 1550 Hb variants are reported in the database. They could lead to Hb polymerization, Hb instability, altered oxygen affinity and decreased oxygen-carrying capacity of Hb or have no clinical manifestations. In India, ethnic diversity, consanguinity, regional variations and migration result in the presence of different Hb variants. We have compiled all the variants of α, ß and δ globin chains in heterozygous, homozygous and in compound heterozygous forms reported from India in the last 52 years. Of the 63 rare and novel hemoglobin variants reported from India, 22 were α-globin chain variants, 37 were ß-globin chain variants and 4 were δ-globin chain variants. Twelve novel Hb variants (Hb J Rajappan, Hb Koya Dora, Hb Rampa, Hb Godavari, Hb Chandigarh, Hb D Agri, Hb Lucknow, Hb Vellore, Hb Midnapore, Hb Bijnor, Hb A2Tianhe and Hb A2Saurashtra) were identified among persons of Indian origin. Majority of them were picked up on HPLC. Some of the variants like Hb Titusville, Hb Shimonoseki, Hb Chandigarh, Hb D Agri, Hb Yaizu and Hb Vellore eluted in the HbS window whereas variants like HbD Iran, Hb St. Louis, Hb G Coushata, HbM Saskatoon, Hb Lucknow, Hb Grange-Blanche and Hb Tianshui showed falsely elevated HbA2. Hence, careful and systematic investigations are required to identify them.

Role of Oxidative Stress and the Protective Effect of Fermented Papaya Preparation in Sickle Cell Disease.

Fermented papaya preparation (FPP) is the source of antioxidants that may help in reducing the complications associated with oxidative stress and may improve the quality of life in sickle cell disease patients. In this study, we assessed the in vitro effect of FPP on sickled red blood cells (RBCs) using oxidative stress markers and observed that FPP has the potential to reduce the oxidative stress. Scanning electron microscopy (SEM) and eosin 5' malaemide (E5'M) dye test showed that FPP protects red cell morphology against the oxidative stress. Liquid chromatography mass spectrometry (LCMS) analysis of FPP suggests the presence of essential amino acids, vitamin D3, and its derivatives. Fermented papaya preparation can be of benefit either in reducing oxidative stress parameters or in preventing pathophysiological events in the sickle cell disease patients.

Newborn Screening and Clinical Profile of Children With Sickle Cell Disease in a Tribal Area of Gujarat.

OBJECTIVE: To present the result of newborn sickle cell disease (SCD) screening and clinical profile of SCD newborns in a tribal area of Gujarat. METHODS: We screened all newborns of sickle cell trait (SCT) and SCD mothers for SCD using high-performance liquid chromatography (HPLC) within two days of birth at a secondary care hospital in a tribal area in Gujarat from 2014 to 2019. Newborns with SCD were registered under an information technology based platform for hospital-based comprehensive care. Neonates were followed prospectively every 3 months. If they missed the clinic visit, a medical counsellor visited them at home to collect the required information. RESULTS: Out of 2492 newborns screened, 87 (3.5%) were diagnosed with SCD. Among the 67 newborns screened for alpha-thalassemia deletion, 64 (95.4%) of babies had alpha-thalassemia deletion. We recorded total 554 clinic visits over the period of 221.5 person-years. The rates of acute febrile illness, painful crisis, hospitalization and severe anemia were 42.9, 14.9, 14.9 and 4.5 per 100 person-year, respectively. Two deaths were recorded, and 5 babies (5.7%) had severe SCD. CONCLUSION: We found a high prevalence of alpha thalassemia deletion among newborn SCD cohort in tribal area of Gujarat, and 70% babies had atleast one clinical complication on follow-up.

Erythrocytes as a preferential target of oxidative stress in blood.

Red blood cells (RBC) are specifically differentiated to transport oxygen and carbon dioxide in the blood and they lack most organelles, including mitochondria. The autoxidation of hemoglobin constitutes a major source of reactive oxygen species (ROS). Nitric oxide, which is produced by endothelial nitric oxide synthase (NOS3) or via the hemoglobin-mediated conversion of nitrite, interacts with ROS and results in the production of reactive nitrogen oxide species. Herein we present an overview of anemic diseases that are closely related to oxidative damage. Because the compensation of proteins by means of gene expression does not proceed in enucleated cells, antioxidative and redox systems play more important roles in maintaining the homeostasis of RBC against oxidative insult compared to ordinary cells. Defects in hemoglobin and enzymes that are involved in energy production and redox reactions largely trigger oxidative damage to RBC. The results of studies using genetically modified mice suggest that antioxidative enzymes, notably superoxide dismutase 1 and peroxiredoxin 2, play essential roles in coping with oxidative damage in erythroid cells, and their absence limits erythropoiesis, the life-span of RBC and consequently results in the development of anemia. The degeneration of the machinery involved in the proteolytic removal of damaged proteins appears to be associated with hemolytic events. The ubiquitin-proteasome system is the dominant machinery, not only for the proteolytic removal of damaged proteins in erythroid cells but also for the development of erythropoiesis. Hence, despite the fact that it is less abundant in RBC compared to ordinary cells, the aberrant ubiquitin-proteasome system may be associated with the development of anemic diseases via the accumulation of damaged proteins, as typified in sickle cell disease, and impaired erythropoiesis.

Newborn Screening for Sickle Cell Disease Among Tribal Populations in the States of Gujarat and Madhya Pradesh in India: Evaluation and Outcome Over 6 Years.

Sickle cell disease (SCD) poses considerable public health problems in India. This study was undertaken to understand the clinical course of SCD among children identified during newborn screening programmes in Gujarat and Madhya Pradesh where the frequency of the HbS gene is high. A total of 8,916 newborn babies 8,411 from Gujarat and 505 from Madhya Pradesh were screened over 6 years (2010-2016) using HPLC and the diagnosis was confirmed by molecular analysis in a subset. A total of 128 babies (122 Gujarat, 6 Madhya Pradesh) were identified with sickle cell disease, of whom 87 (69 HbSS, 18 HbS-ß thalassemia) from Gujarat were followed for 0.5-6.6 years. Acute painful events, severe anemia and fever with infections were the major complications and 23 babies required hospitalization. Severe to moderate clinical presentation was found in 13.8% babies with SCD whereas, 86.2% babies had a milder presentation. Presence of ameliorating factors (α-thalassemia and Xmn 1 polymorphism) did not have a discernible effect on the clinical severity. Parents of babies with SCD were educated and counseled for home care. Distribution of mobile phones to 44 families having babies with SCD was beneficial as it allowed regular contact with patients and their families. Genetic counseling to the affected families has increased the awareness and acceptance for prenatal diagnosis and 18 couples opted for prenatal diagnosis in subsequent pregnancies. SCD is not always mild among tribal groups in India. Therefore, facilities for early diagnosis and prophylactic treatment in the tertiary care centers should be made available. The difficulties in regular follow up of the babies in remote rural areas have also been highlighted.

Prevalence and spectrum of mutations causing G6PD deficiency in Indian populations.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human erythroenzymopathy affecting around 10% of the world population. India is endemic for malaria and antimalarial drugs are known to induce haemolysis in G6PD deficient individuals. Here we report the prevalence as well as the molecular diversity of G6PD deficiency in geographical regions of India. METHODS AND RESULTS: A total of 20,896 individuals (11,838 males and 9058 females) were screened by DPIP dye decolorisation method followed by quantitation of G6PD enzyme activity on the suspected samples. Molecular analysis was undertaken in a total of 350 G6PD deficient individuals by PCR-RFLP and DNA sequencing. A structural characteristic of the novel variant was deduced by using DynaMut web-server. The prevalence rate of G6PD deficiency varied between 0.8 and 6.3% with an overall prevalence of 1.9%. A total of twelve mutations were identified. Of the total deleterious alleles detected G6PD Orissa (56.5%) was found to be the most predominant variant followed by G6PD Mediterranean (23.6%). G6PD Mediterranean, G6PD Kaiping and G6PD Mahidol were found to be severely deficient variant and 14.1% of them showed undetectable activity. A novel mutation c.544C➔G (R182G) in exon 6 was identified in one tribal male where substitution of arginine by glycine, likely causes the alteration in the alpha helix leading to disruption of secondary structure of the protein. CONCLUSION: There are large differences in the distribution of G6PD causal variants between Indian states, and this may have implications for the treatment in the malaria endemic areas.

Prevalence of globin gene modifiers encountered in fetuses during antenatal diagnosis of hemoglobinopathies.

INTRODUCTION: The hemoglobinopathies are the commonest group of single gene disorders in the Indian subcontinent. Although genetic modifiers are known to have a remarkable effect on phenotypic expression, the effects of the possible co-inheritance of different modifiers are not taken into account during prenatal diagnosis. The present study was undertaken to look for the frequency of globin gene modifiers like the types of ß-globin gene mutations, α thalassemia, α gene triplication, and the Xmn1 polymorphism in fetuses during antenatal diagnosis of hemoglobinopathies. MATERIALS AND METHODS: A total of 580 fetuses with different diagnoses were screened for the presence of genetic modifiers. RESULTS: Twenty-two different ß-globin gene mutations were identified of which 3.5% were milder mutations. Among the affected fetuses, 29.6% of the ß-thalassemia major and 52.9% of the sickle cell anemia (SCA) fetuses had one genetic modifier while 3.7% of the ß-thalassemia major and 41.1% of the SCA fetuses had co-inherited two modifiers. α-gene triplication was detected in 16 (3.5%) ß-thalassemia/sickle cell heterozygous and normal fetuses of which 5 babies (2 ß-thalassemia heterozygous and 3 normal) could be followed up. Of the 2 ß-thalassemia heterozygous babies, one had a severe clinical presentation. CONCLUSION: Many fetuses had one or two gene modifiers. However, the impact of these on ameliorating the severity of the disease could not be evaluated as all the fetuses with ß thalassemia major or sickle cell disease were terminated. Parents having heterozygous fetuses with α gene triplication should be followed up periodically after birth for better management of these babies.

Multicenter Evaluation of HemoTypeSC as a Point-of-Care Sickle Cell Disease Rapid Diagnostic Test for Newborns and Adults Across India.

OBJECTIVES: Sickle cell anemia is the commonest genetic disorder in India, and the frequency of the sickle cell gene is very high in the remote tribal areas where facilities are generally limited. Therefore, a rapid and affordable point-of-care test for sickle cell disease is needed. METHODS: The diagnostic accuracy of HemoTypeSC was evaluated against automated high-performance liquid chromatography (HPLC) as the gold standard for its efficacy in a newborn screening program. RESULTS: A total of 1,559 individuals (980 newborns and 579 adults) from four participating centers were analyzed by both methods. HemoTypeSC correctly identified 209 of 211 total hemoglobin (Hb) SS cases, for a 99.1%/99.9% total HbSS sensitivity/specificity. Overall, HemoTypeSC exhibited sensitivity and specificity of 98.1% and 99.1% for all possible phenotypes (HbAA, HbAS, and HbSS) detected. HPLC is relatively expensive and not available in most laboratories in remote tribal areas. CONCLUSIONS: We conclude that the rapid, point-of-care testing device HemoTypeSC test is suitable for population and newborn screening for the HbS phenotype.

G6PD A- is the major cause of G6PD deficiency among the Siddis of Karnataka, India.

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human erythroenzymopathy affecting more than 400 million people worldwide. G6PD deficiency was reported in India more than 50 years ago and the prevalence rate varies from 5.7% to 27.9% in different caste and tribal groups.Aim: To study the prevalence of, and the mutations causing, G6PD deficiency among the Siddis of Karnataka.Subjects and methods: A total of 755 individuals were screened using the DPIP dye decolorisation method and the deficiency was further confirmed by quantitative assay. Molecular characterisation was performed by PCR-RFLP method and DNA sequencing. Biochemical characterisation was performed as per WHO criteria.Results: Of the 755 individuals, 71 individuals (9.4%) were found to be G6PD deficient with an enzyme activity ranging from 0.02 to 3.83 IU/gm Hb. Mutational analysis could be performed on 49 G6PD deficient individuals and 45 (91.8%) of them showed the presence of the G6PD A- variant while the remaining 4 (8.2%) had the G6PD Kerala-Kalyan mutation. Microsatellite analysis in G6PD A- individuals showed the presence of 166/195 bp, AC/CTT alleles.Conclusions: G6PD deficiencies among the Siddis are predominantly due to G6PD A- mutation. Furthermore, biochemical parameters and the microsatellite repeat markers in the Siddi A- chromosome confirmed they are African descendants with Indian admixture.

Red cell distribution width and its association with mortality in neonatal sepsis.

OBJECTIVE: Neonatal sepsis is a major cause of mortality in the developing countries. However, with current severity scores and laboratory parameters, predicting outcomes of neonatal sepsis is a serious challenge. Red cell distribution width (RDW) is a readily available pragmatic means to predict outcomes of various comorbidities in adults and children, without causing any additional blood loss. However, its utility in neonates remains unexplored. Hence, the objective of the present study was to evaluate the association of RDW with neonatal sepsis and its role as a predictive marker for mortality. METHODS: This Prospective observational study was carried out in a Level IIIB NICU for a period of 3 years. It involved comparison of RDW values of septic neonates with those of controls (matched for gestational age and birth weight) with an equal allocation ratio. A total of 251 septic neonates along with 251 controls >28 weeks of gestational age were enrolled. The RDW was derived from complete blood count done within first 6 hours of life. After arranging the RDW (median; interquartile range (IQR)), the values were categorized as those above the 50th percentile i.e. ≥20% and those below the 50th percentile i.e. <20%. The cumulative survival rates of the above two groups were assessed using the Kaplan-Meier curve and the log rank test. RESULTS: RDW levels were significantly higher among the neonatal sepsis cases (19.90%) as compared to the controls (18.90%) with a p value of < .001. RDW was significantly higher amongst the nonsurvivors than survivors (p < .003). Kaplan-Meier curve showed that septic neonates having RDW values ≥20% had significantly increased mortality (p < .02) with a hazard ratio of 0.5. CONCLUSIONS: High RDW is associated with neonatal sepsis and is an independent outcome predictor for mortality associated with neonatal sepsis.

Red Cell Distribution Width (RDW): Normative Data in Indian Neonates.

Red cell distribution width (RDW) is altered because of prematurity and fetal growth restriction (FGR). We conducted a prospective observational study to determine normal RDW values in Indian neonates (N=964) with significant FGR. Mean RDW values in preterm neonates were higher than term neonates (P<0.0004). The RDW values in Indian neonates (with significant FGR) were higher than their western counterparts (P<0.0001). The mean RDW values for different gestational ages in Indian neonates are higher than those observed in other studies. This could be attributable to the FGR component among Indian neonates.

The spatial epidemiology of sickle-cell anaemia in India.

Sickle-cell anaemia (SCA) is a neglected chronic disorder of increasing global health importance, with India estimated to have the second highest burden of the disease. In the country, SCA is particularly prevalent in scheduled populations, which comprise the most socioeconomically disadvantaged communities. We compiled a geodatabase of a substantial number of SCA surveys carried out in India over the last decade. Using generalised additive models and bootstrapping methods, we generated the first India-specific model-based map of sickle-cell allele frequency which accounts for the district-level distribution of scheduled and non-scheduled populations. Where possible, we derived state- and district-level estimates of the number of SCA newborns in 2020 in the two groups. Through the inclusion of an additional 158 data points and 1.3 million individuals, we considerably increased the amount of data in our mapping evidence-base compared to previous studies. Highest predicted frequencies of up to 10% spanned central India, whilst a hotspot of ~12% was observed in Jammu and Kashmir. Evidence was heavily biased towards scheduled populations and remained limited for non-scheduled populations, which can lead to considerable uncertainties in newborn estimates at national and state level. This has important implications for health policy and planning. By taking population composition into account, we have generated maps and estimates that better reflect the complex epidemiology of SCA in India and in turn provide more reliable estimates of its burden in the vast country. This work was supported by European Union's Seventh Framework Programme (FP7//2007-2013)/European Research Council [268904 - DIVERSITY]; and the Newton-Bhabha Fund [227756052 to CH].

Effect of Assorted Globin Haplotypes and α-Thalassemia on the Clinical Heterogeneity of Hb S-ß-Thalassemia.

Hemoglobinopathies and thalassemias are the most commonly encountered monogenic disorders of blood in humans, posing a major genetic and public health problem round the globe. Hb S (HBB: c.20A>T)-ß-thalassemia (ß-thal) is a compound aberrant heterozygosity with inconsistent phenotypic expression, which are poorly described and clinically mapped. Comprehensive genetic characterization of such a population is highly warranted for complete understanding of the clinical heterogeneity, disease prognosis and therapeutic management. In this study, Hb S-ß-thal (n = 60) patients, strictly defined by varying degrees of clinical presentations, were selected to evaluate their genotype-phenotype agreement. Furthermore, ß-globin (n = 120) and α-globin gene clusters (n = 60) were genetically characterized and statistically correlated with clinical terminologies to explain the clinical heterogeneity. Our results revealed the association of the Arab-Indian haplotypes with nine different frameworks of ß-thal together with the modulating role of α-thalassemia (α-thal). The study subjects, including carriers of ß-thal haplotype III [- - - - - - -] (8.0%), presented with varying severe patterns of clinical symptoms such as painful crisis, multiple infections and splenomegaly, as an outcome of significantly less Hb F and higher Hb S levels (p < 0.5). The study findings indicated that together with α-thal, ß-thal haplotypes and Hb F levels, may possibly provide a close justification to support the clinical heterogeneity in the study population.

Genetic lesions in the UGT1A1 genes among Gilbert's syndrome patients from India.

The present study was undertaken to investigate genetic variations present in the coding regions of the UGT1A1 gene among the Gilbert's syndrome patients. Analysis of genetic variations was performed by direct DNA sequencing among the patients that do not have any polymorphic variations in the promoter regions of the UGT1A1 gene. We identified seven different sequence variations among Gilbert's Syndrome patients, of which four were novel. Out of seven variants, six missense and one silent single nucleotide substitutions were present in the UGT1A1 gene. In addition, molecular modeling of UGT1A1 (H55R, P152S and N212H) variants suggested a reduced activity of the enzyme. This study demonstrates that different variations present in the UGT1A1 gene and specifically, the H55R variation had a significant effect on bilirubin levels and could be genetic risk factors for hyperbilirubinemia.

Potential involvement of ubiquitin-proteasome system dysfunction associated with oxidative stress in the pathogenesis of sickle cell disease.

The ubiquitin-proteasome system (UPS) is an important intracellular proteolytic pathway responsible for the degradation of proteins and oxidative damage; hence it plays a central role in maintaining homeostasis of red blood cells (RBCs). The present study investigated the levels of polyubiquitination, the function of proteasomes and effect of hydroxycarbamide (HC) therapy in RBCs from sickle cell disease (SCD) patients. Polyubiquitinated proteins were found to be elevated in untreated SCD (UT-SCD) patients compared to those in HC-treated SCD patients (HC-SCD) and controls. Activities of ß1 and ß2 subunits were a little higher in UT-SCD patients, and much higher proteolytic activities were observed in all three subunits (ß1, ß2 and ß5) of RBCs in HC-SCD patients compared to those of UT-SCD patients and controls, although the protein levels of these subunits remained approximately the same. It is notable that, despite HC therapy, some patients showed persistent complications and accumulation of polyubiquitinated proteins. The enhanced proteasomal activity among HC-treated patients might remove the polyubiquitinated protein and could be one of the important mechanisms of therapeutic action. These findings could be useful to understand the pathophysiology of SCD and its clinical heterogeneity and identify a suitable therapeutic target for the better management of these patients.

Newborn Screening for Hemoglobinopathies and Red Cell Enzymopathies in Tripura State: A Malaria-Endemic State in Northeast India.

Hemoglobinopathies are a group of inherited single gene disorders. There are reports on hemoglobin (Hb) variants identified in the tribal and non-tribal populations of Tripura State in northeastern India. This study aimed to determine the spectrum of hemoglobinopathies and enzymopathies by newborn screening in Tripura State and assess the extent of neonatal jaundice. A total of 2400 cord blood samples were collected and analyzed by high performance liquid chromatography (HPLC). Further confirmation of any abnormal HPLC was done by DNA analysis. The samples were also screened for deficiency of enzymopathies, glucose-6-phosphate dehydrogenase (G6PD) deficiency and pyruvate kinase. Of 2400 cord blood samples screened, 225 (9.3%) were Hb E (HBB: c.79G>A) heterozygotes, 80 (3.3%) were Hb E homozygotes and one carried Hb E-ß-thalassemia (ß-thal). Other Hb abnormalities were also detected including 15 Hb S (HBB: c.20A>T) heterozygotes, two Hb D-Punjab (HBB: c.364G>C) heterozygotes and two compound heterozygotes for Hb D-Punjab and Hb E. Of the 80 homozygous Hb E babies, four were non-tribal and 76 babies were tribal, and 225 patients carried Hb E trait, 141 were tribal, while 84 were non-tribal. Of 40 G6PD deficient babies identified, 13 had coinherited Hb E and two babies had pyruvate kinase deficiency. α Genotyping was performed in 162 affected babies, 50 of them carried α gene deletions. Newborn screening programs for Hb E, other hemoglobinopathies and G6PD deficiency must be encouraged in the malaria-endemic northeastern region of India. Drug-induced hemolysis can also be avoided by screening for G6PD deficiency at birth.

Newborn Screening for Sickle Cell Disease: Indian Experience.

Sickle cell disease (SCD) is a major public health problem in India with the highest prevalence amongst the tribal and some non-tribal ethnic groups. The clinical manifestations are extremely variable ranging from a severe to mild or asymptomatic condition. Early diagnosis and providing care is critical in SCD because of the possibility of lethal complications in early infancy in pre-symptomatic children. Since 2010, neonatal screening programs for SCD have been initiated in a few states of India. A total of 18,003 babies have been screened by automated HPLC using either cord blood samples or heel prick dried blood spots and 2944 and 300 babies were diagnosed as sickle cell carriers and SCD respectively. A follow up of the SCD babies showed considerable variation in the clinical presentation in different population groups, the disease being more severe among non-tribal babies. Around 30% of babies developed serious complications within the first 2 to 2.6 years of life. These pilot studies have demonstrated the feasibility of undertaking newborn screening programs for SCD even in rural areas. A longer follow up of these babies is required and it is important to establish a national newborn screening program for SCD in all of the states where the frequency of the sickle cell gene is very high followed by the development of comprehensive care centers along with counselling and treatment facilities. This comprehensive data will ultimately help us to understand the natural history of SCD in India and also help the Government to formulate strategies for the management and prevention of sickle cell disease in India.

Genetic Variations in Bilirubin Metabolism Genes and Their Association with Unconjugated Hyperbilirubinemia in Adults.

OBJECTIVE: The present study was undertaken to investigate the genotype and allele frequencies of the variants in the four bilirubin metabolism genes (UGT1A1, OATP2, HMOX1, and BLVRA) and their association with hyperbilirubinemia. MATERIAL AND METHODS: Genotyping of 17 genetic variants was performed in 115 adults with hyperbilirubinemia and 150 controls by PCR-RFLP, GeneScan analysis, and direct DNA sequencing. RESULTS: Genetic polymorphisms of the UGT1A1 promoter, specifically the T-3279G phenobarbital-responsive enhancer module and (TA)7 dinucleotide repeat, as well as the intron and coding region variants of the OATP2, HMOX1, and BLVRA genes, were significantly higher among the cases than the controls. Further, nearly 82% of the cases showed the presence of significantly four or more variants as compared to 37% of the controls (P < 0.0001) and the mean total serum bilirubin levels also increased according to the number of variants co-expressed. CONCLUSIONS: This study demonstrates that polymorphisms in the bilirubin metabolism genes had a significant effect on bilirubin levels and could be genetic risk factors for hyperbilirubinemia.