A successful twin pregnancy in a patient with HbE-ß-thalassemia in western India.

Improvements in medical facilities have helped a large number of clinically severe hemoglobin E (HbE)-ß-thalassemia patients reach adulthood. Consequently, there is a new challenge, that of managing women with HbE-ß-thalassemia during pregnancy. In particular, they have a high risk of abortion, preterm delivery, intrauterine growth restriction, and thromboembolism. A 27-year-old HbE-ß-thalassemia patient on regular transfusion, who was splenectomized and heptatitis C (HCV)-positive, conceived for the first time without any infertility treatment. However, there was incomplete abortion with heavy bleeding at 3 months of gestation, which required bilateral uterine artery angiography. The angiogram showed the left uterine artery to be moderately hypertrophied. This was embolized with 300-500 micron polyvinyl alcohol (PVA) to stop the bleeding. Soon after, she conceived again with a twin pregnancy, and at 33.3 weeks of gestation, there was a normal delivery of twin girls without any postpartum hemorrhage or perineal tear. Both babies were given prematurity care. The mother and children were both normal up till the last follow-up 18 months after delivery, and both the girls are HbE heterozygous. Thorough monitoring of endocrine functions along with proper management of transfusions and iron overload can help in reducing the complications related to pregnancy in these patients.

Clinical spectrum and molecular basis of recessive congenital methemoglobinemia in India.

We report the clinical features and molecular characterization of 23 patients with cyanosis due to NADH-cytochrome b5 reductase (NADH-CYB5R) deficiency from India. The patients with type I recessive congenital methemoglobinemia (RCM) presented with mild to severe cyanosis only whereas patients with type II RCM had cyanosis associated with severe neurological impairment. Thirteen mutations were identified which included 11 missense mutations causing single amino acid changes (p.Arg49Trp, p.Arg58Gln, p.Pro145Ser, p.Gly155Glu, p.Arg160Pro, p.Met177Ile, p.Met177Val, p.Ile178Thr, p.Ala179Thr, p.Thr238Met, and p.Val253Met), one stop codon mutation (p.Trp236X) and one splice-site mutation (p.Gly76Ser). Seven of these mutations (p.Arg50Trp, p.Gly155Glu, p.Arg160Pro, p.Met177Ile, p.Met177Val, p.Ile178Thr, and p.Thr238Met) were novel. Two mutations (p.Gly76Ser and p.Trp236X) were identified for the first time in the homozygous state globally causing type II RCM. We used the three-dimensional (3D) structure of human erythrocyte NADH-CYB5R to evaluate the protein structural context of the affected residues. Our data provides a rationale for the observed enzyme deficiency and contributes to a better understanding of the genotype-phenotype correlation in NADH-CYB5R deficiency.

Detection of fetal mutations causing hemoglobinopathies by non-invasive prenatal diagnosis from maternal plasma.

BACKGROUND: Prenatal diagnosis of hemoglobinopathies enables couples at risk to have a healthy child. Currently used fetal sampling procedures are invasive with some risk of miscarriage. A non-invasive approach to obtain fetal deoxyribonucleic acid (DNA) for diagnosis would eliminate this risk. AIM: To develop and evaluate a non-invasive prenatal diagnostic approach for hemoglobinopathies using cell-free fetal DNA circulating in the maternal plasma. SETTINGS AND DESIGN: Couples referred to us for prenatal diagnosis of hemoglobinopathies where the maternal and paternal mutations were different were included in the study. MATERIALS AND METHODS: Maternal peripheral blood was collected at different periods of gestation before the invasive fetal sampling procedure was done. The blood was centrifuged to isolate the plasma and prepare DNA. A size separation approach was used to isolate fetal DNA. Nested polymerase chain reaction (PCR)-based protocols were developed for detection of the presence or absence of the paternal mutation. RESULTS AND CONCLUSIONS: There were 30 couples where the parental mutations were different. Of these, in 14 cases the paternal mutation was absent and in 16 cases it was present in the fetus. Using cell-free fetal DNA from maternal plasma, the absence of the paternal mutation was accurately determined in 12 of the 14 cases and the presence of the paternal mutation was correctly identified in 12 of the 16 cases. Thus, this non-invasive approach gave comparable results to those obtained by the conventional invasive fetal sampling methods in 24 cases giving an accuracy of 80.0%. Although the nested PCR approach enabled amplification of small quantities of cell-free DNA from maternal plasma at different periods of gestation after size separation to eliminate the more abundant maternal DNA, an accurate diagnosis of the presence or absence of the paternal mutation in the fetus was not possible in all cases to make it clinically applicable.

Prevalence of ß-thalassemia and other haemoglobinopathies in six cities in India: a multicentre study.

The population of India is extremely diverse comprising of more than 3,000 ethnic groups who still follow endogamy. Haemoglobinopathies are the commonest hereditary disorders in India and pose a major health problem. The data on the prevalence of ß-thalassemias and other haemoglobinopathies in different caste/ethnic groups of India is scarce. Therefore the present multicentre study was undertaken in six cities of six states of India (Maharashtra, Gujarat, West Bengal, Assam, Karnataka and Punjab) to determine the prevalence of haemoglobinopathies in different caste/ethnic groups using uniform methodology. Fifty-six thousand seven hundred eighty individuals (college students and pregnant women) from different caste/ethnic groups were screened. RBC indices were measured on an automated haematology counter while the percentage of HbA(2), HbF and other abnormal Hb variants were estimated by HPLC on the Variant Hemoglobin Testing System. The overall prevalence of ß-thalassemia trait was 2.78 % and varied from 1.48 to 3.64 % in different states, while the prevalence of ß-thalassemia trait in 59 ethnic groups varied from 0 to 9.3 %. HbE trait was mainly seen in Dibrugarh in Assam (23.9 %) and Kolkata in West Bengal (3.92 %). In six ethnic groups from Assam, the prevalence of HbE trait varied from 41.1 to 66.7 %. Few subjects with δß-thalassemia, HPFH, HbS trait, HbD trait, HbE homozygous and HbE ß-thalassemia as well as HbS homozygous and HbS-ß-thalassemia (<1 %) were also identified. This is the first large multicentre study covering cities from different regions of the country for screening for ß-thalassemia carriers and other haemoglobinopathies where uniform protocols and methodology was followed and quality control ensured by the co-ordinating centre. This study also shows that establishment of centres for screening for ß-thalassemia and other haemoglobinopathies is possible in medical colleges. Creating awareness, screening and counselling can be done at these centres. This experience will help to formulate a national thalassemia control programme in India.

Invasive & non-invasive approaches for prenatal diagnosis of haemoglobinopathies: experiences from India.

The thalassaemias and sickle cell disease are the commonest monogenic disorders in India. There are an estimated 7500 - 12,000 babies with ß-thalassaemia major born every year in the country. While the overall prevalence of carriers in different States varies from 1.5 to 4 per cent, recent work has shown considerable variations in frequencies even within States. Thus, micromapping would help to determine the true burden of the disease. Although screening in antenatal clinics is being done at many centres, only 15-20 per cent of pregnant women register in antenatal clinics in public hospitals in the first trimester of pregnancy. There are only a handful of centres in major cities in this vast country where prenatal diagnosis is done. There is considerable molecular heterogeneity with 64 mutations identified, of which 6 to 7 common mutations account for 80-90 per cent of mutant alleles. First trimester foetal diagnosis is done by chorionic villus sampling (CVS) and DNA analysis using reverse dot blot hybridization, amplification refractory mutation system (ARMS) and DNA sequencing. Second trimester diagnosis is done by cordocentesis and foetal blood analysis on HPLC at a few centres. Our experience on prenatal diagnosis of haemoglobinopathies in 2221 pregnancies has shown that >90 per cent of couples were referred for prenatal diagnosis of ß-thalassaemia after having one or more affected children while about 35 per cent of couples were referred for prenatal diagnosis of sickle cell disorders prospectively. There is a clear need for more data from India on non-invasive approaches for prenatal diagnosis.

Evaluation of a capillary blood collection system for screening for hemoglobinopathies in remote areas.

Accurate estimation of hemoglobin (Hbs) A, Hb A(2), Hb F and abnormal Hb is required for diagnosis of hemoglobinopathies and genetic counseling. High pressure liquid chromatography (HPLC) is the most suitable approach available. But for 70% of the rural Indian population, HPLC analysis facilities are not available and screening would require transportation of samples to laboratories in bigger cities. We thus evaluated the feasibility of using a kit designed for measuring Hb A(1c) using capillary blood for collection and preservation of samples over a period of 15 days at different temperatures for screening for hemoglobinopathies. Capillary blood (5 microl) of 90 individuals was collected in the capillary collection system and run on the Variant Hemoglobin Testing System on days 1, 3, 5, 8, 12 and 15 after incubation at 4, 22, 37, 42 and 50 degrees C. The stability of different Hbs varied at different temperatures. The stability was maintained for 12 to 15 days by most of the samples up to 37 degrees C. Hb E was stable for 3 days up to at 37 degrees C and Hb D and Hb Q for 3 days up to 42 degrees C. This capillary blood collection system would have tremendous potential for sample collection and transportation under adverse climatic conditions for screening of hemoglobinopathies in remote areas in different countries.

Microsatellite diversity among the primitive tribes of India.

The present study was undertaken to determine the extent of diversity at 12 microsatellite short tandem repeat (STR) loci in seven primitive tribal populations of India with diverse linguistic and geographic backgrounds. DNA samples of 160 unrelated individuals were analyzed for 12 STR loci by multiplex polymerase chain reaction (PCR). Gene diversity analysis suggested that the average heterozygosity was uniformly high ( >0.7) in these groups and varied from 0.705 to 0.794. The Hardy-Weinberg equilibrium analysis revealed that these populations were in genetic equilibrium at almost all the loci. The overall G(ST) value was high (G(ST) = 0.051; range between 0.026 and 0.098 among the loci), reflecting the degree of differentiation/heterogeneity of seven populations studied for these loci. The cluster analysis and multidimensional scaling of genetic distances reveal two broad clusters of populations, besides Moolu Kurumba maintaining their distinct genetic identity vis-à-vis other populations. The genetic affinity for the three tribes of the Indo-European family could be explained based on geography and Language but not for the four Dravidian tribes as reflected by the NJT and MDS plots. For the overall data, the insignificant MANTEL correlations between genetic, linguistic and geographic distances suggest that the genetic variation among these tribes is not patterned along geographic and/or linguistic lines.

Iron deficiency anaemia in sickle cell disorders in India.

BACKGROUND & OBJECTIVE: Iron deficiency anaemia (IDA) is uncommon in individuals with sickle cell disease (SCD) because of availability of an adequate iron source potentially from increased red cell turnover and from blood transfusions. Also, iron deficiency anaemia can often go unnoticed because the sickle cell disease patients are already anaemic. Iron deficiency in sickle cell patients may result in lowering the intracellular haemoglobin concentration and this may ameliorate sickling. The present study was undertaken to determine the prevalence of iron deficiency anaemia and the response of iron supplementation in sickle cell disorders in tribal population of the four States viz. Maharashtra, Gujarat, Orissa and Tamil Nadu. METHODS: A total of 8434 individuals (7105 AA, 1267 AS and 62 SS) were tested for zinc protoporphyrin/haem (ZPP/H) ratio and haemoglobin levels. Twenty two sickle cell anaemia (SS), 47 sickle cell trait (AS) and 150 normal control (AA) individuals who were iron deficient, were given iron therapy for a period of 12 wk and the laboratory investigations were repeated at the 13th wk. RESULTS: Sixty seven per cent of subjects with sickle cell anaemia and 26 per cent with sickle cell trait had elevated ZPP/H ratios (>80 micromol/mol) as against 22.8 per cent of normal individuals. The elevated ZPP/H ratios is an indicator of microcytic anaemia of iron deficiency. Following iron therapy, an improvement in the Hb levels and ZPP/H ratios was observed in both sickle cell disorders and normal individual cases. INTERPRETATION & CONCLUSION: This study suggests that iron deficiency anaemia is an important problem in Indian sickle cell anaemia patients and iron supplementation should be given only in proven cases of iron deficiency anaemia.

A novel R198H mutation in the glucose-6-phosphate dehydrogenase gene in the tribal groups of the Nilgiris in Southern India.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common red cell enzymopathy among humans. In India, G6PD Mediterranean, G6PD Orissa, and G6PD Kerala-Kalyan are the three common mutations which account almost 90% of G6PD deficiency. Here we describe G6PD Coimbra, an unreported variant from India, and a novel 593 G --> A mutation in exon 6 with an amino acid change of Arg 198 His, among the tribal groups of the Nilgiris in Southern India. Further, this novel mutation was structurally characterized and it was found that the mutation is located at the end of the coenzyme domain, which may cause enzyme instability.

First-trimester prenatal diagnosis of pyruvate kinase deficiency in an Indian family with the pyruvate kinase-Amish mutation.

Pyruvate kinase (PK) deficiency is a rare red cell glycolytic enzymopathy. The purpose of the present investigation was to offer prenatal diagnosis for PK deficiency to a couple who had a previous child with severe enzyme deficiency and congenital non-spherocytic hemolytic anemia. PK deficiency was identified in the family by assaying the enzyme activity in red cells. Chorionic villus sampling was performed in an 11-week gestation and the mutation was located in exon 10 of the PKLR gene characterized by polymerase chain reaction and using restriction endonuclease digestion with the MspI enzyme, which was confirmed by DNA sequencing on the ABI 310 DNA sequencer. Both the parents were heterozygous for the 1436G-->A [479 Arg-->His] mutation in exon 10 and the proband was homozygous for this mutation. The fetus was also heterozygous for this mutation and the pregnancy was continued. Prenatal diagnosis allowed the parents with a severely affected child with PK deficiency to have the reproductive choice of having the fetus tested in a subsequent pregnancy.

HPLC studies in hemoglobinopathies.

An accurate diagnosis of beta -thalassemia carriers, homozygous patients and identification of different structural hemoglobin variants is important for epidemiological studies as well as for management and prevention of the major hemoglobin disorders. There are many electrophoretic and chromatographic approaches for estimation of HbA2 and Hb F but cation exchange HPLC (CE-HPLC)using automated dedicated machines like the Variant Hb testing system have become the method of choice for these investigations. CE-HPLC also helps in the presumptive identification of many abnormal hemoglobin variants and has been useful for both neonatal screening of sickle cell disease as well as second trimester prenatal diagnosis of thalassemia by fetal blood analysis. Other applications of HPLC in hemoglobinopathies include separation of globin chains, measuring the ratio of gamma globin chains (Ggamma/Agamma) and the recently described denaturing HPLC for detecting mutations in both alpha and beta globin genes.

First-trimester prenatal diagnosis of pyruvate kinase deficiency in an Indian family with the pyruvate kinase-Amish mutation

Pyruvate kinase (PK) deficiency is a rare red cell glycolytic enzymopathy. The purpose of the present investigation was to offer prenatal diagnosis for PK deficiency to a couple who had a previous child with severe enzyme deficiency and congenital non-spherocytic hemolytic anemia. PK deficiency was identified in the family by assaying the enzyme activity in red cells. Chorionic villus sampling was performed in an 11-week gestation and the mutation was located in exon 10 of the PKLR gene characterized by polymerase chain reaction and using restriction endonuclease digestion with the MspI enzyme, which was confirmed by DNA sequencing on the ABI 310 DNA sequencer. Both the parents were heterozygous for the 1436G-->A [479 Arg-->His] mutation in exon 10 and the proband was homozygous for this mutation. The fetus was also heterozygous for this mutation and the pregnancy was continued. Prenatal diagnosis allowed the parents with a severely affected child with PK deficiency to have the reproductive choice of having the fetus tested in a subsequent pregnancy.

Experience with eosin-5'-maleimide as a diagnostic tool for red cell membrane cytoskeleton disorders.

The diagnosis of hereditary spherocytosis (HS) is based on red cell morphology and other conventional tests such as osmotic fragility, autohemolysis and acidified glycerol lysis. However, milder cases are at times difficult to diagnose. Confirmation by red blood cell (RBC) membrane protein analysis is not possible in most laboratories. Recently, a flow cytometric method has been described for quantitating the fluorescence intensity of intact red cells after incubation with the dye eosin-5'-maleimide (EMA), which binds specifically to the anion transport protein (band-3) at lysine-430. This has been shown to be an effective screening test for red cell membrane disorders. We evaluated the usefulness of this approach for screening membrane protein disorders such as HS and hereditary elliptocytosis (HE) and its value in discriminating this group from other hemolytic anemias, such as glucose-6-phosphate dehydrogenase (G6PD) deficiency, beta-thalassemia trait, sickle cell anemia and autoimmune hemolytic anemia. Fluorescence intensity, expressed in mean channel fluorescence (MCF) units, was determined using a Becton Dickinson FACS Caliber flow cytometer. Membrane protein analysis was carried out by sodium dodecyl sulfate-polyacrylamide gel eletrophoresis (SDS-PAGE). RBCs from patients with HS and HE gave significantly lower MCF values (P < 0.001) than the normal control group and other patient groups. The diagnosis of HS in four cases was confirmed by RBC membrane protein electrophoresis and all showed a deficiency of spectrin. The advantage of the EMA dye method are its specificity for membrane disorders, as well as being a simple, user-friendly and rapid method which is inexpensive, provided a flow cytometer is available.

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.

Genetic disorders in haematological practice in India.

Haemoglobinopathies represent a significant national health burden in India. The distribution of specific disorders varies geographically and by community. Heterozygote frequencies of beta-thalassaemia range from 1 to 15%, resulting in an estimated 20 million carriers. HbS is mainly present in tribal and non-caste communities, with carrier prevalences of up to 40%. By comparison, alpha-thalassaemia carriers are found in both the caste and tribal communities, and can reach a frequency of >90% in the latter case. Community control of haemoglobinopathies relies mainly on out-reach education programmes and genetic counselling, with antenatal diagnosis offered in specific major centres. Only partial data are available on the prevalence of haemophilia, but it has been estimated that there are some 50,000 affected individuals nationwide, with an additional 1,500 new cases born each year. RFLP-based techniques have been established to detect mutations in the factor VIII and IX genes, enabling the limited introduction of carrier detection and antenatal diagnosis.

High prevalence of G6PD deficiency in Vataliya Prajapati community in western India.

OBJECTIVE: Sporadic cases of drug-induced haemolytic anaemia due to glucose-6-phosphate dehydrogenase (G6PD) deficiency in patients belonging to Vataliya Prajapati community prompted us to study the prevalence of G6PD deficiency in the community. METHODS: Screening for G6PD deficiency was carried out using the dichlorophenol-indophenol (DPIP) dye decolorization method. RESULTS: A total of 471 individuals were screened. Of these, 385 unrelated individuals were considered to calculate the prevalence of G6PD deficiency. Among 272 unrelated males, 76 persons (27.94%) and among 113 unrelated females, 11 individuals (9.73%) were found to be G6PD deficient. A quantitative assay on 41 of the G6PD deficient samples showed the enzyme activity ranged from 0-0.5 unit/ml RBC/min. CONCLUSION: The prevalence of G6PD deficiency in Vataliya Prajapatis community was found to be the highest ever reported in the Indian caste-groups population studied so far.