Thalassemia is a blood disorder in which the body does not make appropriate types of haemoglobin. An adult haemoglobin molecule is formed by symmetric pairing of alpha and beta globin chains with an iron molecule in the centre. In beta-thalassemia, there is a defective synthesis of beta-chain and manifestations are due to the excessive production of alpha chains. This chain imbalance leads to reduced erythropoiesis.
β-Thalassemia is one of the most common genetic diseases with an estimated 1.5% of the global population (around 80 to 90 million) as carriers. It is estimated that about 60,000 to 70,000 symptomatic babies with β-Thalassemia are born every year. Most of them are dying due to lack of facilities either because of shortage of blood, unavailability or unaffordability of iron chelating agents. Currently no cure is available except bone marrow transplantation.
Thalassemia is caused by an array of different mutations in the HBB gene. A variety of genetic events including single nucleotide substitutions, deletions or insertions can cause the disease.
Though different point-of-care assays are available commercially, most antibody tests cannot be used in patients who have received red blood cell transfusions recently. Genetic testing is the gold-standard and accurate diagnostic for β-Thalassemia and can aid in accurate diagnosis, evidence based genetic counselling and can help avoid additional unnecessary clinical investigations.
What and Why
While genetic tests have been available for decades, the tests are cumbersome, inaccessible, costly and often not scalable for large-scale applications in carrier screening and patient diagnosis and therefore was limited to a few special settings. The availability of newer high-throughput and scaleable genetic sequencing approaches have the potential to change this for Thalassemia.
As part of the Genomics for Understanding Rare Diseases India Alliance Network (GUaRDIAN) initiative and network at CSIR-IGIB, we have been piloting various accessible and affordable approaches for genetic testing of prevalent genetic diseases in India. This specific initiative has been designed to pilot sequencing-based screening / diagnosis of β-Thalassemia in community settings in India.
Participating in the Collaboration
Clinicians, Hospitals and patient support organisations including Thalassemia societies can partner in the pilot initiative. Each collaborating centre could avail screening for approximately 25-100 patients / family members depending on the availability of resources. The costs for the genetic test would be covered by a research grant to CSIR-IGIB and therefore would be available free-of-cost to the individual.
All individuals would require to be counselled and referred by a practising clinician and have to consent to genetic testing / screening. The results of genetic testing would be shared back with the clinician for counselling and action and would also be made available on the digital platform for reporting. Please do not refer to cases which require an immediate turnaround of reporting as in cases of prenatal screening or testing.