SICKLE CELL AND THALASSAEMIA (Syllabus: GS Paper 3 – Sci and Tech)

Context: Recently, the UK drug regulator granted approval for a gene therapy designed to treat sickle cell disease and thalassaemia, marking a significant breakthrough in medical advancements.

• This is the first licensed therapy in the world based on the gene editing technology Crispr-Cas9 which earned its innovators a Nobel Prize in 2020.

How does the therapy work?

• Both sickle cell disease and thalassaemia are caused by errors in the gene for hemoglobin, a protein in the red blood cells that carry oxygen to organs and tissues.
• The therapy uses the patient's own blood stem cells, which are precisely edited using Crispr-Cas9.
• A gene called BCL11A, which is crucial for switching from foetal to adult hemoglobin, is targeted by the therapy.
• Foetal haemoglobin, which is naturally present in everyone at birth, does not carry the same abnormalities as adult hemoglobin. The therapy uses the body's own mechanisms to start producing more of this foetal hemoglobin, alleviating the symptoms of the two conditions.

Sickle Cell Anaemia

• About: It is one of a group of inherited disorders known as sickle cell disease.
• Cause: It is caused by a change in the gene that tells the body to make the iron-rich compound in red blood cells called haemoglobin.
• Symptoms: Extreme tiredness or irritability due to anaemia, painful swelling of hands and feet, and jaundice in the early stages.
• Treatment: Blood transfusions alleviate anaemia and lower pain crisis risk.

Thalassemia

• About: Thalassemia is an inherited blood disorder caused when the body doesn’t make enough of a protein called hemoglobin, an important part of red blood cells. 
• India also has the largest number of children with thalassemia major in the world.