In India, beta-thalassemia is one of the most common single-gene blood disorders. Approximately one lakh individuals are affected by it, and every year around 10,000-15,000 are being added.
Beta Thalassemia is caused due to genetic changes in the HBB gene, which codes for the beta chain of haemoglobin. This results in reduced synthesis of a part of haemoglobin, which carries oxygen to all the body cells, leading to severe anaemia and other systemic complications. It can only be managed by frequent, lifelong blood transfusions every 10-15 days. For the long-term control, bone marrow or stem cell transplantation may required. Genetic counselling is an integral part of the diagnosis, prevention and management of this condition.
India is estimated to have 42 million carriers of β-thalassemia, where they have one normal copy and one abnormal copy of the HBB gene. The first step to understanding the risk for future generations is to know whether the couple is a carrier of Beta-thalassemia.
A simple blood test (RBC indices and peripheral smear examination) followed by an examination of the Hb pattern on HPLC or capillary electrophoresis can tell us an individual's carrier status. They then need to be confirmed by a genetic test to know the change in the HBB gene.
Considering the increasing number of thalassemia cases in India, National Health Mission India has formulated guidelines on Hemoglobinopathies, including Beta-thalassemia (2016). They aim to provide optimal treatment to those affected and prevention through carrier screening, genetic counselling, and prenatal diagnosis.
The following ways have been proposed for the same
1) Carrying out awareness, education and screening programmes in the community and schools,
2) Establishing laboratories for carrier screening for hemoglobinopathies and screening newborns for sickle cell disease at the district level,
3) To prevent the birth of children affected with thalassemia major or sickle cell disease, screening of pregnant women and their husbands and,
4) Establishing prenatal diagnostic centres in Medical Colleges in the States where required. In addition, treatment can be provided by
A) the development of treatment centres with the help of State Health Departments,
B) providing facilities for bone marrow transplants, and
C) In major cities facilitating the establishment of donor registries and public cord blood banks to provide a source of HLA matched stem cells through convergence with other programmes.
Where cure is complicated and sometimes unaffordable, prevention is the only option to decrease the incidence of severe debilitating genetic disorders.
Carrier screening is one way of knowing the carrier status of the couple for genetic diseases and thus providing reproductive options to couples at risk.
Creating awareness, providing affordable testing options, and giving appropriate genetic counselling to such families will impact the overall management of thalassemia and other hemoglobinopathies.
(Sushma Patil is Senior Genetic Counsellor, Neuberg Center for Genomic Medicine)