Sickle cell anaemia

Sickle cell anemia is a genetic disorder affecting red blood cells, causing them to become rigid and sickle-shaped due to a mutation in the hemoglobin gene. This can lead to blockages in blood vessels, causing pain and potentially life-threatening complications like strokes. The disorder is inherited in a recessive manner, requiring two copies of the faulty allele for the disease to manifest. Carriers have one copy and are generally asymptomatic. Sickle cell anemia is prevalent in regions affected by malaria, as the sickle cell trait offers some protection against the disease. The malaria parasite struggles to survive in the altered red blood cells of carriers, breaking its life cycle.

What causes the red blood cells in sickle cell anemia to become inflexible and sickle-shaped?

• A lack of vitamin B12

• A deficiency in iron

• A mutation in the hemoglobin gene

• An excess of white blood cells

How many copies of the faulty allele are required for a person to have sickle cell anemia?

• Four copies

• Two copies

• One copy

• Three copies

What is the likelihood of children being carriers if both parents are carriers of the sickle cell allele?

• 0%

• 25%

• 50%

• 100%

In which regions is sickle cell anemia most prevalent?

• South America and Antarctica

• Australia and New Zealand

• North America and Europe

• Central Africa and parts of India

How does carrying the sickle cell allele provide protection against malaria?

• It increases the production of white blood cells

• It causes red blood cells to burst before the malaria parasite can develop

• It prevents mosquitoes from biting

• It strengthens the immune system