|Year : 2012 | Volume
| Issue : 4 | Page : 297-300
Screening for thalassemia and other hemoglobinopathies in a tertiary care hospital of West Bengal: Implications for population screening
Bhawna Bhutoria Jain1, Rabindra Nath Roy2, Sulekha Ghosh3, Tapan Ghosh4, Uma Banerjee5, Subodh Kumar Bhattacharya6
1 Assistant Professor, Department of Pathology, Burdwan Medical College, West Bengal, India
2 Associate Professor, Department of Community Medicine, Burdwan Medical College, West Bengal, India
3 Associate Professor, Department of Pathology, Burdwan Medical College, West Bengal, India
4 Demonstrator, Department of Pathology, Burdwan Medical College, West Bengal, India
5 Professor & Head, Department of Pathology, Burdwan Medical College, West Bengal, India
6 MSVP, Burdwan Medical College, West Bengal, India
|Date of Web Publication||24-Jan-2013|
Bhawna Bhutoria Jain
Assistant Professor, Department of Pathology, Burdwan Medical College, Burdwan, West-Bengal
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Hemoglobinopathies are common genetic disorders of hemoglobin, which can be prevented by population screening and offering genetic counseling. In absence of population-based screening for hemoglobinopathies, the hospital-based diagnosis register provide idea about the extent of problem in the community. The present study was undertaken to find out the burden of hemoglobinopathies and spectrum of this disorders among the population who were screened in the hospital-based screening program. A record-basedanalysis of subjects who underwent screening for hemoglobinopathies in Burdwan Medical College and Hospital over a period of 3 years and 4 months revealed that overall 29.3% of subjects were positive for hemoglobinopathies. Beta thalassemia heterozygous was the most commonhemoglobinopathy in this region closely followed by hemoglobin E heterozygous. In view of high prevalence of hemoglobinopathies in this region, a routine premarital screening program is needed for identification and prevention of high-risk marriages.
Keywords: Carrier screening, Hemoglobinopathies, Thalassaemia
|How to cite this article:|
Jain BB, Roy RN, Ghosh S, Ghosh T, Banerjee U, Bhattacharya SK. Screening for thalassemia and other hemoglobinopathies in a tertiary care hospital of West Bengal: Implications for population screening. Indian J Public Health 2012;56:297-300
|How to cite this URL:|
Jain BB, Roy RN, Ghosh S, Ghosh T, Banerjee U, Bhattacharya SK. Screening for thalassemia and other hemoglobinopathies in a tertiary care hospital of West Bengal: Implications for population screening. Indian J Public Health [serial online] 2012 [cited 2020 Apr 6];56:297-300. Available from: http://www.ijph.in/text.asp?2012/56/4/297/106419
Hemoglobinopathies are a group of genetic disorders of hemoglobin in which there is abnormal production or structure of thehemoglobinmolecule. These hereditary disorders are major public health problem in many parts of the world including India. The clinical spectrum of the disorders varies from asymptomatic conditions to serious disorders like thalassemia major that requires regular blood transfusions and extensive medical care. World Health Organization (WHO) figures estimates that 7% of world population is carrier for hemoglobin disorders.  Population screening has identified the prevalence of β-thalassemia carrier status as high as 17% in certain communities in India. 
Prospective prevention through population screening and genetic counseling is the best possible strategy for prevention of these disorders. As the exact data pertaining to the prevalence of hemoglobinopathies in this region is scarce, we considered it important to find out the extent of burden of hemoglobinopathies in this region.
The present study attempted to find out the occurrence of hemoglobinopathies and the spectrum of different types of hemoglobinopathies in the study population.
We conducted a cross-sectional descriptive study based on records of screening program for hemoglobinopathies in the hematology unit of the pathology department of Burdwan Medical College and Hospital (BMCH). The BMCH is one of the Government medical colleges in the state of West Bengal, India that predominantly serves the rural people from the adjacent districts. The study population comprised of all the subjects who were screened for hemoglobinopathies in BMCH from January 2006 to April 2009. Medical records of all these subjects were reviewed. Twenty-five subjects were excluded due to incomplete information; thus final sample size of 3823 was analyzed. Blood samples anticoagulated in ethylenediaminetetraacetic acid (EDTA) were run in automated hematology analyzer MS-5 for counts and red blood cell indices. The diagnosis was verified by hemoglobin electrophoresis at pH 8.9 and quantification of A2 fraction of adult hemoglobin by elution method. A value more than 3.5% of A2 fraction of hemoglobin was taken as the cutoff point for determining the beta thalassemia trait and more than 10% was assumed to be hemoglobin E. Hemoglobin F (HbF) was measured by Singers alkali denaturation method. , Sickling test with sodium metabisulfite was performed in suspected sickle cases.  In all positive cases, family members were also screened. When confirmatory diagnosis was not possible with hemoglobin electrophoresis; patients were referred to higher center in Kolkata for final diagnosis.
For analysis purpose the study population was divided into two groups; First group (At-risk screening group) included the individuals with suspected risk of thalassemia who are either referred from out-patient departments of hospital to pathology department or anybody with suspicion of carrier in the family reporting voluntarily for screening. Second group (Opportunistic screening group) included student, premarital, preconception (postmarital screening before planning child birth) and antenatal subjects who apparently did not have any suspicion of risk of carrier state and for this group routine screening was performed. Collected data was fed on Microsoft Excel worksheet. Proportions were computed in appropriate situations. To find out any association between categorical data, chi-square test was employed using Epi-info software version 3.5.1.
A total of 3823 individuals were screened for hemoglobinopathies, of them 59.14% and 40.86% were in 'At-risk screening' and 'Opportunistic screening' group, respectively. Overall 29.32% of subjects were positive for hemoglobinopathies.
In 'At-risk screening' group 1267 (56.03%) were normal and 994 (43.97%) had hemoglobinopathies while in 'Opportunistic screening' group, 1435 (91.87%) and 127 (8.13%) were normal and hemoglobinopathies, respectively. The positivity rate for hemoglobinopathies varied among the different categories of subjects. This difference was not statistically significant (P = 0.11) in the 'Opportunistic screening' group; however, it was statistically significant (P = 0.00) in the 'At-risk screening' group' [Table 1].
|Table 1: Proportion of subjects with hemoglobinopathies in study population|
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[Table 2] depicts the age and sex distribution and the spectrum of different types of hemoglobinopathies among the study population. It was observed that 54.15% were in age group of 13-36 years followed by 39.88% in 0-12 years. However, majority of beta homozygous (85.84%) and E-beta thalassemia (52.98%) were in pediatric age group (0-12years) as they show their symptoms early in life.
|Table 2: Age– sex distribution and spectrum of hemoglobinopathies at the time of screening|
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Evaluation of spectrum shows that β-thalassemia heterozygote (trait) constitute 55.84% of all hemoglobinopathies followed by 15.70% in hemoglobin E heterozygote. All these subjects were asymptomatic and hence considered as carriers of abnormal gene. The E-beta thalassemia and cases of beta thalassemia (B-homozygous) constituted about 11.95% and 9.45% of total hemoglobinopathies, respectively. Other hemoglobinopathies such as sickle cell disorders were also observed in this region.
On analyzing the sex ratio, it was observed that 32.04% (588/1835) of male and 26.81% (533/1988) of female subjects were positive for hemoglobinopathies.
Hemoglobinopathies constitute the most commonly inherited genetic disorders and the distribution varies geographically and by community.  In India, the frequency of beta thalassemia ranges from 3.5% to 15% in general population.  In the present study, the overall 29.32% of subjects had a hemoglobinopathy; the higher rate is due to inclusion of suspected risk group of population. We divided high-risk cases as a separate group, which included subjects having suspicion of hemoglobinopathy. This approach increased the detection rate among the family members that was as high as 75%. Using cascade screening approach, Ajit et al., identified 5-6 times higher percentage of beta thalassemia carriers. 
We noted positivity rate of and 28.62-75.40% among 'At- risk' group and 6.75-10.87% in 'Opportunistic' group. However, Sur et al., observed 11.25% and 55.26% in similar population in West Bengal.  The higher prevalence among the suspect risk group may be due to difference in screening criteria.
The screening of school children is also a good strategy to create awareness. We observed 6.75% positivity among screened students. Slight lower rate of 2.68% and 5.47% of beta thalassemia among students were reported from Mumbai and Delhi, respectively. 
In our study, out of 286 antenatal mothers screened, 9.09% were positive for hemoglobinopathy. Their spouses were also tested. All of them were counseled if their husbands also showed a positive diagnosis and they were referred for prenatal diagnosis (screening of inutero fetus by chorionic villous biopsy). If the fetus is detected to be homozygous for beta thalassemia gene, parents are advised to terminate the pregnancy. Colah et al., identified 37 couples at risk of which 15 couples had a prenatal diagnosis and 4 couples opted for termination of pregnancy.
Of 276 premarital individuals screened 10% showed some hemoglobinopathies. In Turkey 2.6% of thalassemia trait and 0.11% sickle trait was reported among the premarital subjects. 
The present study provides the broad overview of the burden and spectrum of hemoglobinopathies in this region of country. Along with B-homozygous, E hemoglobinopathies is also prevalent in this region. In this perspective, we emphasize that a routine premarital screening program is needed for identification and prevention of high-risk marriages. Nevertheless, mass awareness, knowledge generation, and genetic counseling are still a vital requisite.
| Acknowledgement|| |
We acknowledge to the technical staff of haematology department and thalassemia counselor Sudesna for helping us in this work.
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[Table 1], [Table 2]
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