What is the extent of the thalassemia burden in India and how can it be managed?

The National Thalassemia Control Programme aims to prevent thalassemia by promoting awareness and testing for carrier states during marriage or initial prenatal check-ups | Image used for representational purpose
| Photo Credit: Getty Images

Thalassemia and Sickle Cell Anaemia are the commonest single-gene disorders globally, and it is estimated that around 3,00,000 to 4,00,000 babies with a severe haemoglobin disorder are born each year.

Beta Thalassemia occurs due to a mutation in the beta globin gene, which is essential for production of normal haemoglobin, the protein inside our red blood cells which carries oxygen from the lungs to all the tissues in the body. We have two beta globin genes — and if one is mutated, then the individual is a carrier with no symptoms and can lead a normal life with haemoglobin Hb~9 grams/dL and smaller red blood cells (low MCVs).

However, if both beta globin genes are mutated, then there is severe anaemia detected at around six months after birth and these children require life-long, regular blood transfusions to maintain haemoglobin levels, ensure growth and development and prevent enlargement of the liver and spleen. If two carriers marry, then there is a 25% chance of having a thalassemia major baby.

Carrier status can be confirmed by doing a full blood count and HPLC (high performance liquid chromatography) which shows a low Hb ~9gm% MCV ~65 and Hb A2 above 3.5% on HPLC. Once the diagnosis of thalassemia is confirmed, genetic tests can be done to check which mutation is causing the problem in the individual family.

Managing thalassemia

Once the diagnosis is confirmed, parents with an affected child have three options:

Life long transfusions every 3-4 weeks to keep Hb ~ 9 gm%: Each transfusion loads the body with about 200 mg of iron, which the system is unable to excrete. This iron, which accumulates in the liver and heart, can cause damage, so these children require chelation (removal of iron with an oral medical called Deferasirox or a sub cutaneous injection called desferal given over 12 hours with a small pump every night.) All of this is a tremendous burden for parents with an affected child.

Bone marrow transplantation or more correctly, hematopoietic stem cell transplantation (HSCT): In this procedure if the patient has a HLA (tissue type) matched sibling who is either normal or a carrier, then stem cells from the bone marrow or blood are harvested and transfused into the affected patient after destroying the immune system and stem cells of the patient.

The procedure has an 85% success rate and children can live a normal life after the transplant. However, there may be some complications like rejection of the transplanted stem cells and graft versus host disease (GVHD) where the donor’s immune system attacks the recipient’s skin, liver, and intestine. Coal India is providing ₹10 lakh per patient through the Thalassemia Bal Sewa CSR program implemented through the Union Ministry of Health and the NGO Thalassaemics India.

Gene therapy: In this treatment, the stem cells of the patient are collected, and the defected gene is repaired (Gene editing) or replaced with a normal gene. Currently this treatment is available abroad and costs around $ 2 million. It could become available in India at a much lower cost in the future.

The burden in India

Beta thalassemia and sickle cell disorders pose a significant health burden in India. The average prevalence of beta thalassemia carriers is 3-4% in the country, which translates to 35 to 45 million carriers in our multi-ethnic and culturally and linguistically diverse population of 1.21 billion people, which also includes around 8% of tribal groups according to the Census of India 2011. Several ethnic groups have a much higher prevalence (4-17%).

Limited micro-mapping has shown an uneven distribution in frequencies of beta thalassemia carriers in different districts in Maharashtra (1-6%) and Gujarat (0-9.5%) within small geographic regions. The expected annual births of beta thalassemia major babies were also calculated for each district in these two states. The rate of homozygosity (affected) per 1,000 births annually was 0.28 in Maharashtra and 0.39 in Gujarat.

Prevention is key

Therefore, prevention is most important for a country like India, and this can been achieved with a National Thalassemia Control Programme in which education of the general public on the importance of testing for carrier states at the time of marriage or during the first antenatal check-up after conception is carried out through the year, for example with a short, 30-second video clip on TV. If both parents are carriers, then antenatal diagnosis is possible by a simple procedure done at 12 weeks of pregnancy, where a chorionic villus sample (CVS) is obtained from the placenta with a needle, under local anaesthesia. This is tested for the mutations causing thalassemia.

It also vital that affected children are cared for with safe blood transfusion and affordable chelation.

(Dr Mammen Chandyis a consultant haematologist at Naruvi Hospital, Vellore. [email protected])