A comprehensive screening program for β-thalassemia and other hemoglobinopathies in the Hooghly District of West Bengal, India, dealing with 21 137 cases

Prevalence and Management of β-Thalassemia in India

India bears a huge burden of hemoglobinopathies, and the most prevalent is thalassemia. The different types of thalassemia include minor, major and intermedia, based on the α/β-globin chain inequality. This review aimed to understand the current prevalence of thalassemia in different regions of India and communities affected by it, along with the management of β-thalassemia major (β-TM) and β-thalassemia (β-thal) minor patients. A comprehensive electronic search for relevant articles was conducted using two databases, i.e. PubMed and Science Direct. Articles published in English from India between January 2009 and September 2021 were included. Studies from other countries, genetic and molecular characterization studies, and articles published in other languages were excluded. The prevalence of β-thal trait in Central India ranged between 1.4 and 3.4%, while 0.94% β-TM was reported among the patients with anemia. In South India, the prevalence of β-thal trait was between 8.50 and 37.90% and β-TM was reported to be between 2.30 and 7.47%. Northern and Western Indian states had a higher thalassemic burden. In Eastern India, tribal populations had a higher prevalence of β-thal trait (0.00-30.50%), β-TM (0.36-13.20%) and other hemoglobinopathies [Hb E (HBB: c.79G>A)/β-thal] (0.04-15.45%) than nontribal populations. Additionally, scheduled castes, scheduled tribes and other backward classes of low socioeconomic status and low literacy rates were affected by β-thal. Almost all Indian states reported β-thal; however, it is mostly concentrated in eastern and western parts of the country. Well-integrated strategies and effective implementation are needed at State and National levels to minimize the burden of β-thal.

A decision support scheme for beta thalassemia and HbE carrier screening

The most effective way to combat β-thalassemias is to prevent the birth of children with thalassemia major. Therefore, a cost-effective screening method is essential to identify β-thalassemia traits (BTT) and differentiate normal individuals from carriers. We considered five hematological parameters to formulate two separate scoring mechanisms, one for BTT detection, and another for joint determination of hemoglobin E (HbE) trait and BTT by employing decision trees, Naïve Bayes classifier, and Artificial neural network frameworks on data collected from the Postgraduate Institute of Medical Education and Research, Chandigarh, India. We validated both the scores on two different data sets and found 100% sensitivity of both the scores with their respective threshold values. The results revealed the specificity of the screening scores to be 79.25% and 91.74% for BTT and 58.62% and 78.03% for the joint score of HbE and BTT, respectively. A lower Youden’s index was measured for the two scores compared to some existing indices. Therefore, the proposed scores can obviate a large portion of the population from expensive high-performance liquid chromatography (HPLC) analysis during the screening of BTT, and joint determination of BTT and HbE, respectively, thereby saving significant resources and cost currently being utilized for screening purpose.

Population Screening for Hemoglobinopathies

Hemoglobinopathies are the most common single-gene disorders in the world. Their prevalence is predicted to increase in the future, and low-income hemoglobinopathy-endemic regions need to manage most of the world's affected persons. International organizations, governments, and other stakeholders have initiated national or regional prevention programs in both endemic and nonendemic countries by performing population screening for α- and β-thalassemia, HbE disease, and sickle cell disease in neonates, adolescents, reproductive-age adults (preconceptionally or in the early antenatal period), and family members of diagnosed cases. The main aim of screening is to reduce the number of affected births and, in the case of sickle cell disease, reduce childhood morbidity and mortality. Screening strategies vary depending on the population group, but a few common screening test methods are universally used. We discuss the salient features of population-screening programs around the globe as well as current and proposed screening test methodologies.