Malay B. Mukherjee

Sickle cell disease in India.

Purpose of reviewSickle cell disease (SCD) poses a considerable health burden in India. This review focuses on the recent initiatives to understand the variable phenotypes, the role of hydroxyurea in patients with the Asian haplotype and the feasibility of newborn screening, awareness and control programs. Recent findingsA systematic long follow up of patients in central India has documented the clinical events and the causes of significant morbidity and mortality. Fixed low dose hydroxyurea was sufficient for a clinical and hematological response in severe patients who had high baseline fetal hemoglobin (HbF) levels. Follow-up of birth cohorts of SCD babies initiated recently has shown that in central India babies clinically present with early and severe anemia, requiring blood transfusions, and septicemia, which are the most common complications, whereas babies from tribal communities in south Gujarat have no severe complications. Greater awareness has led to increasing requests for prenatal diagnosis. SummarySCD in India is not uniformly mild despite high fetal hemoglobin levels. The benefits of comprehensive care and hydroxyurea therapy have been demonstrated. Newborn screening is acceptable and is beginning to throw light on the natural history of the disease. The central and state governments are now supporting the establishment of centers for the diagnosis of patients and comprehensive care.

Effect of α-thalassemia on sickle-cell anemia linked to the Arab-Indian haplotype in India

Two population groups from Western India with a high prevalence of the βs gene, one tribal (Valsad) and the other nontribal (Nagpur), were studied. The βs gene frequency in both populations was similar (0.22 vs. 0.23), but not the clinical expression of sickle‐cell anemia (SS): the sickle homozygotes in the tribal group appeared to have a mild clinical course, whereas the majority in the nontribal group exhibited a more severe clinical phenotype. Both tribal and nontribal SS patients had a similarly high mean hemoglobin (Hb)F expression (18.5% vs. 15.5%) and a high number of F cells (72.3% vs. 66.6%). DNA analysis of the β‐globin gene cluster region revealed that in these two populations, this portion of DNA was identical with and corresponded to the typical Arab‐Indian haplotype. Nevertheless, in heterozygotes, the mean βs expression was lower (27.9%) in the tribal as compared to the nontribal group (35.5%). The major epistatic factor distinguishing the milder presentation in tribals vs. a more severe manifestation in nontribals was the very high frequency (0.97) of the α‐thalassemia gene in the former as compared to the latter (0.24). We conclude that the phenotypic expression of sickle‐cell anemia, linked to the Arab‐India haplotype and expressing similar levels of HbF and F cells, is not uniformly mild in India and that α‐thalassemia is a powerful and additional epistatic factor in the Indian subcontinent. Am. J. Hematol. 55:104‐109, 1997.

Glucose–6–phosphate dehydrogenase deficiency in India

Glucose–6–phosphate dehydrogenase (G6PD) deficiency is the commonest red cell enzymopathy in humans and has an X-linked inheritance. It has been reported from India more than 30 years ago and the prevalence varies from 0–27% in different caste, ethnic and linguistic groups. The major clinical manifestations are drug induced hemolytic anemia, neonatal jaundice and chronic non–spherocytic hemolytic anemia. Individuals with G6PD deficiency have a selective advantage against falciparum malaria. Thirteen biochemically characterized variants have been reported from India. At the molecular level, G6PD Mediterranean is the most common deficient variant in the caste groups whereas, G6PD Orissa is more prevalent among the tribal of India. The third common variant seen in India is G6PD Kerala–Kalyan

Association of (GT)n Repeats Promoter Polymorphism of Heme Oxygenase-1 Gene with Serum Bilirubin Levels in Healthy Indian Adults

AIM The present study was undertaken to investigate a length polymorphism of (GT)n repeats of the heme oxygenase-1 (HMOX-1) gene and its association with serum bilirubin levels in apparently healthy adults. METHODS A total of 211 individuals (normal hematology and liver function test) with bilirubin levels of 1.7 to 22.2 μM were studied. The (GT)n repeats were analyzed by PCR and subsequent sizing by capillary electrophoresis on the ABI Prism 310 Genetic Analyzer. RESULTS Polymorphisms of the (GT)n repeats were grouped into three classes: short (S) alleles (<20 repeats), intermediate (M) alleles (20-28 repeats), and long (L) alleles (≥ 29 repeats). The frequencies of the S, M, and L allele groups were 0.10, 0.49, and 0.41, respectively. Carriers of short alleles had significantly higher mean bilirubin levels (13.8 ± 5.10 μM) compared with others (9.18 ± 3.73 μM, p < 0.001). CONCLUSION Short (GT)n alleles of the HMOX-1 gene promoter could be a genetic risk factor for hyperbilirubinemia.

Clinical, hematologic and molecular variability of sickle cell-β thalassemia in western India

BACKGROUND: Sickle cell-β thalassemia (HbS-β thalassemia) is a sickling disorder of varying severity, which results from compound heterozygosity for sickle cell trait and β thalassemia trait. The present study was undertaken to determine the genetic factors responsible for the clinical variability of HbS-β thalassemia patients from western India. MATERIALS AND METHODS: Twenty-one HbS-β thalassemia cases with variable clinical manifestations were investigated. The α and β globin gene clusters were studied by molecular analysis. RESULTS: Thirteen patients showed milder clinical presentation as against eight patients who had severe clinical manifestations. Four β thalassemia mutations were identified: IVS 1-5 (G→C), codon 15 (G→A), codon 30 (G→C) and codon 8/9 (+G). α thalassemia and XmnI polymorphism in homozygous condition (+/+) were found to be common among the milder cases. The βS chromosomes were linked to the typical Arab-Indian haplotype (#31). Framework (FW) linkage studies showed that four β thalassemia mutations were associated with different β globin gene frameworks. Linkage of codon 15 (G→A) mutation to FW2 is being observed for the first time. CONCLUSION: The phenotypic expression of HbS-β thalassemia is not uniformly mild and α thalassemia and XmnI polymorphism in homozygous condition (+/+) are additional genetic factors modulating the severity of the disease in the Indian subcontinent.

Molecular characterization of G6PD Insuli—a novel 989 CGC → CAC (330 Arg → His) mutation in the Indian population

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common red cell enzymopathy among humans. G6PD deficiency was reported in India more than 30 years ago and about 13 biochemically characterized variants have been reported. We now describe the molecular characterization of a distinct biochemical variant from India which was previously characterized by us as a unique Class IV variant with fast electrophoretic mobility. The sequence of the G6PD gene from this variant has revealed the presence of a novel 989 G --> A mutation in exon 9 with a predicted amino acid change of Arg330His.

Red Cell Genetic Abnormalities, [Beta]-Globin Gene Haplotypes, and APOB Polymorphisms in the Great Andamanese, A Primitive Negrito Tribe of Andaman and Nicobar Islands, India

The Great Andamanese are a primitive Negrito tribe of the Andaman and Nicobar Islands, India, with a total population of 37. We studied 29 individuals from eight families from this population for abnormal hemoglobins, G6PD deficiency, DNA haplotypes, and apolipoprotein B (APOB, gene) polymorphism. Hb E was detected in five individuals, the prevalence of Hb E heterozygotes being 14.3%. One individual had b-thalassemia trait. One female was G6PD deficient and showed the G6PD Orissa mutation. Haplotype analysis of the b-globin gene cluster showed that the bE chromosomes were linked to two haplotypes (- - - - - + + and + + - + + + +) representing the framework 1 gene, whereas the bA chromosomes showed eight different haplotypic patterns corresponding to framework 1 and 3 genes. APOB polymorphism analysis showed that the 631-base-pair (bp) allele was the predominant one with a high homozygosity rate, which could be due to the higher rate of inbreeding in this isolated group. The presence of Hb E and our findings on haplotype analysis supports the hypothesis that the Great Andamanese are reasonably believed to be the surviving representatives of the Negrito race that once flourished in the entire Southeast Asian region in ancient times.

Clinical Diversity of Sickle Cell Disease in Western India – Influence of Genetic Factors

Accessible online at: www.karger.com/journals/aha We read with interest the report entitled ‘Sickle cell disease in Brazzaville, Congo: genetical, hematological, biochemical and clinical aspects’ by Mouele et al. [1]. We have been studying the natural history, clinical and molecular mechanism of sickle cell disease in western India for 1 decade. We have studied 143 sickle cell disease patients aged 6–36 years, with varying clinical manifestations from tribal and nontribal populations. The severity grading was used according to the NIH (USA protocol). DNA samples of these patients were analyzed for ßS haplotypes and ·-genotypes by PCR [2] and Southern blot hybridization [3] to understand the clinical diversity among these groups. A summary of our findings is presented in table 1. Part of these data have been published elsewhere [4, 5]. Mouele et al. [1] have not correlated the influence of ·-thalassemia with the severity of sickle cell disease, whereas our study showed an ameliorating effect of the –·3.7 deletion on the severity of sickle cell disease. The incidence of splenomegaly in Congolese patients was similar to our patients with the –·3.7 deletion. Similar observations have been made by Kar et al. [6] from Orissa populations in the eastern part of India. Unlike their series, none of our patients had leg ulcers. Contrary to this, other studies have shown that the rate of painful crisis, acute chest syndrome and aseptic necrosis is more common among the patients with ·-thalassemia [7, 8]. Hence, the influence of ·thalassemia on the clinical severity of sickle cell disease is controversial. In the majority of Congolese patients, the ßS gene was linked with the severe Bantu haplotype while all our patients had the milder Arab-Indian haplotype with much higher HbF levels (14.5 vs. 8.8%). This could offer an added advantage to our patients. Further, the majority of our patients were identified during population surveys, where cases with a milder presentation could be picked up in contrast to the hospital-based study of Mouele et al. [1] which is more biased as more severely affected patients may be included. Thus, our study indicates that the clinical manifestation of sickle cell disease was influenced by ·-thalassemia rather than the ßS haplotype or higher HbF levels in Indians.

Sickle cell disease in tribal populations in India

The sickle gene is widespread among many tribal population groups in India with prevalence of heterozygotes varying from 1-40 per cent. Co-inheritance of the sickle gene with β-thalassaemia, HbD Punjab and glucose-6-phosphate dehydrogenase (G6PD) deficiency has also been reported. Most of the screening programmes in India now use high performance liquid chromatography (HPLC) analysis although the solubility test is also sensitive and cheap. Sickle cell disease (SCD) among tribal populations is generally milder than among non-tribal groups with fewer episodes of painful crises, infections, acute chest syndrome and need for hospitalization. This has partly been attributed to the very high prevalence of α-thalassaemia among these tribes as well as higher foetal haemoglobin levels. However, the clinical presentation is variable with many cases having a severe presentation. There is not much information available on maternal and perinatal outcome in tribal women with sickle cell disease. Newborn screening programmes for SCD have recently been initiated in Maharashtra, Gujarat, Odisha and Chattisgarh and monitoring these birth cohorts will help to understand the natural history of SCD in India. Prenatal diagnosis is acceptable by tribal families in India. The Indian Council of Medical Research and the National Rural Health Mission in different States are undertaking outreach programmes for better management and control of the disease.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency among tribal populations of India - Country scenario.

It is believed that the tribal people, who constitute 8.6 per cent of the total population (2011 census of India), are the original inhabitants of India. Glucose-6-phosphate-dehydrogenase (G6PD) deficiency is an X-linked genetic defect, affecting around 400 million people worldwide and is characterized by considerable biochemical and molecular heterogeneity. Deficiency of this enzyme is highly polymorphic in those areas where malaria is/has been endemic. G6PD deficiency was reported from India more than 50 years ago. The prevalence varies from 2.3 to 27.0 per cent with an overall prevalence of 7.7 per cent in different tribal groups. Since the tribal populations live in remote areas where malaria is/has been endemic, irrational use of antimalarial drugs could result in an increased number of cases with drug induced haemolysis. Therefore, before giving antimalarial therapy, routine screening for G6PD deficiency should be undertaken in those tribal communities where its prevalence is high.