Ans. Thalassemia is an inherited (passed down from parents to children via genes) blood disorder that occurs when the body doesn't produce enough haemoglobin, a protein that is essential for the formation of red blood cells.Thalassemia is caused by mutations in the DNA of cells that produce haemoglobin, the substance found in red blood cells that transports oxygen throughout the body. The mutations that cause thalassemia are passed down from parents to children.