Spectrum of Haemoglobinopathies in a Tertiary Care Hospital of Armed Forces

Borderline HbA2 levels: Dilemma in diagnosis of beta-thalassemia carriers

There is inconsistency in the exact definition of diagnostic levels of HbA₂ for β thalassemia trait. While many laboratories consider HbA₂ ≥4.0 % diagnostic, still others consider HbA₂ ≥3.3 % or HbA₂ ≥3.5 % as the cut-off for establishing β thalassemia carrier diagnosis. This is because, over the years, studies have described β thalassemia carriers showing HbA₂ levels that lie above the normal range of HbA₂ but below the typical carrier range of β thalassemia. These, "borderline HbA₂ levels", though not detrimental to health, are significant in β thalassemia carrier diagnosis because they can lead to misinterpretation of results. In this review, we have evaluated the prevalence of borderline HbA₂ levels and discussed the causes of borderline HbA₂ values. We have also compiled an extensive catalogue of β globin gene defects associated with borderline HbA₂ levels and have discussed strategies to avoid misdiagnosing borderline HbA₂ β thalassemia carriers. Our analysis of studies that have delineated the cause of borderline HbA₂ levels in different populations shows that 35.4 % [626/1766] of all individuals with borderline HbA₂ levels carry a molecular defect. Among the positive samples, 17 % [299/1766] show β globin gene defects, 7.7 % [137/1766] show α thalassemia defects, 2.7 % [49/1766] show KLF1 gene mutations, 2.3 % [41/1766] show the co-inheritance of β and α thalassemia, 2.0 % [37/1766] show the co-inheritance of β and δ thalassemia and 1.8 % [32/1766] show α globin gene triplication. It appears that a comprehensive molecular work up of the β globin gene is the only definite method to detect borderline HbA₂ β thalassemia carriers, especially in populations with a high prevalence of the disease. The presence of associated genetic or acquired determinants may subsequently be assessed to identify the cause of borderline HbA₂.

Implications of Population Screening for Thalassemias and Hemoglobinopathies in Rural Areas of West Bengal, India: Report of a 10-Year Study of 287,258 Cases

Thalassemia and hemoglobinopathies are the most common cause of high morbidity and mortality in India. Detection of carriers and premarital counseling play an important role in preventing the birth of a thalassemic child. The present study aimed to detect large numbers of asymptomatic carriers in rural areas of West Bengal, India. The present cross-sectional study was conducted over a period of 10 years. Thalassemia awareness programs and detection camps were organized at the community level. After signed written consent was obtained, the collected blood samples were subjected to a complete blood count (CBC) in an automated blood cell counter and then analyzed by high performance liquid chromatography (HPLC); in difficult cases, samples were sent to the reference laboratory for molecular characterization. Out of 287,258 samples collected, 32,921 (11.46%) cases revealed abnormal hemoglobins (Hbs); of these, 31,782 (11.06%) carried heterozygous states (carriers/traits), and the remainder were either homozygous or compound heterozygous for different hemoglobinopathies. Two common variants were revealed in the study, namely β-thalassemia (β-thal) (7.23%) and Hb E [β26(B8)Glu→Lys, HBB: c.79G>A] (2.77%) traits. Among homozygous or compound heterozygous states, Hb E/β-thal (0.14%) and β-thal major (β-TM) (0.12%) were predominant. In rural areas of West Bengal, the most common Hb variants detected were β-thal and Hb E traits. In view of the high prevalence of hemoglobinopathies in this region, routine premarital screening and genetic counseling should be emphasized and encouraged to prevent the birth of a thalassemic child, and thus curtailing the burden on families and the health economy.

Clinico-Haematological Profile of Hereditary Haemolytic Anaemias in a Tertiary Health Care Hospital in South India

INTRODUCTION

Hereditary haemolytic anaemia is a common inherited disorder causing varying degree of morbidity and mortality. This includes disorders due to haemoglobin defect, membrane defect, and enzyme defect. Among them haemoglobinopathies, a single gene disorder, constitutes the major part of the disorder and is distributed worldwide with an incidence of 5%. These inherited disorders pose a major public health problem and increase the burden both on the patient and the society. Presently, these disorders are not curable but can only be prevented. Improved awareness about these diseases among medical fraternity leading to diagnosis of carrier state, genetic counselling, and antenatal diagnosis may help in decreasing the prevalence of the disease.

AIM

To determine the prevalence of hereditary haemolytic anaemia and to correlate clinical and haematological features.

MATERIALS AND METHODS

The study was carried for duration five and half years (four years of retrospective and one and a half years prospective). All the patients diagnosed as hereditary haemolytic anaemia based on peripheral smear and special haematological investigation were included in the study. The clinical parameters and haematological parameters of all these patients were studied.

RESULTS

A total of 322 cases of hereditary haemolytic anaemia were diagnosed over a period of five and a half years. Of them thalassaemia syndrome constituted 165 cases (51.24%), sickle cell disorders 78 cases (24%), hereditary spherocytosis 43 cases (13.3%), G6PD deficiency 20 cases (6.29%) and HbE disorder 12 cases (3.7%). One case of hereditary elliptocytosis and one case of HbD Punjab was detected. Among thalassaemia syndromes beta thalassaemia was commonest clinically presenting disorder with a high morbidity. Sickle cell anaemia showed a higher level of HbF and a relatively milder clinical course. Hereditary spherocytosis had varied age at presentation. In G6PD deficiency drug induced haemolysis was the commonest clinical presentation. HbE disorders were from the north eastern states.

CONCLUSION

Haemoglobinopathies constitute the major group of hereditary haemolytic anaemia (74%). Genetic counselling is an important step in reducing the incidence of thalassaemia major.

Hemoglobin e syndromes: emerging diagnostic challenge in north India

Hemoglobin E (HbE) is one of the world's most common and important mutations. HbE disorders may be found in heterozygous (AE), homozygous (EE) and compound heterozygous state. It is important to distinguish HbE disorders diagnostically because of marked differences in clinical course among different genotypes. To find out whether RBC indices as obtained from automated cell counter can provide a clue to the diagnosis of HbE disease. This study was carried out in the Department of Clinical Pathology, PGIMER, Dr. Ram Manohar Lohia Hospital, New Delhi. It included antenatal pregnant females brought for routine check-up as well as referred patients suspected of having hemoglobinopathies. High Performance liquid chromatography was used as a confirmatory test for identification of hemoglobinopathy. Total 20 cases of subtype homozygous HbE (3), HbE trait (12) and Eβ-thalassemia (5) were identified. Statistical analysis was done to find out correlation between levels of HBA2, HBF with RBC indices. (a) There was negative correlation between HbA2/E peak values and RBC indices (Mean corpuscular volume (MCV) and Mean corpuscular hemoglobin) among all the three groups taken together. (b) There was positive correlation between HbA2/E and Red cell distribution width (RDW). (c) There was positive correlation between HbF values with MCV. The finding of positive correlation between HbA2/E and RDW may help in differentiating βthal (RDW normal) from HbE/βthal. In a patient with microcytic hypochromic blood picture and increased RDW, diagnosis of HbE/βthal should also be considered along with the more common Iron deficiency anemia. Thus, new insights into the knowledge of these diseases are important because they impart diagnostic challenges to all the experts involved in the treatment of anemic patients.