Sickle cell anaemia | Genetics | Biology | FuseSchool

Summary

Sickle cell anemia is an inherited disorder affecting red blood cells due to a mutation in the hemoglobin gene, causing them to become crescent-shaped and prone to blockages. This can lead to severe pain crises and life-threatening complications. The condition is inherited recessively, requiring two faulty alleles, and is prevalent in regions where malaria is common due to its protective effect against the disease. Carriers have a 50% abnormal hemoglobin, which hinders the malaria parasite's life cycle, thus reducing its prevalence.

Takeaways

• 🧬 Sickle cell anemia is an inherited disorder affecting red blood cells due to a mutation in the hemoglobin gene.
• 🩸 Normal red blood cells are round and flexible, but in sickle cell anemia, they become crescent or 'sickle' shaped due to the faulty hemoglobin.
• 🚫 The misshapen red blood cells can cause blockages in blood vessels, preventing oxygen and glucose from reaching tissues and organs.
• 😖 Sickle cell crises are episodes of severe pain that can last from minutes to weeks and may lead to life-threatening complications.
• 🧬 To have sickle cell anemia, an individual must inherit two copies of the recessive allele, while one copy makes a person a carrier.
• 👨‍👩‍👧‍👦 Carriers have red blood cells with 50% abnormal hemoglobin, making them more fragile but not causing the disease.
• 🌍 The distribution of sickle cell anemia is linked to regions where malaria is prevalent, particularly in central Africa, India, the Middle East, and among people of African descent.
• 🦟 The sickle cell allele offers a protective effect against malaria, as the parasite's life cycle is disrupted in the fragile red blood cells of carriers.
• 📈 The prevalence of sickle cell anemia is higher in malaria regions because carriers have a higher chance of passing on the allele to their children.
• 🌐 There are approximately 4.4 million people worldwide with sickle cell anemia and an additional 43 million carriers.
• 👍 The video encourages viewers to like, subscribe, and comment if they have questions, and also to check out the Few School app for more information.

Q & A

What is sickle cell anemia?

Sickle cell anemia is an inherited disorder that affects red blood cells due to a mutation in the hemoglobin gene, causing them to assume a crescent or 'sickle' shape, which can lead to blockages in blood vessels and a lack of oxygen to tissues and organs.

What role does hemoglobin play in the body?

Hemoglobin is a red protein in red blood cells that carries oxygen throughout the body.

How do red blood cells normally function and what changes in sickle cell anemia?

Normally, red blood cells are round and flexible, allowing them to move easily through narrow blood vessels. In sickle cell anemia, the mutation causes the cells to become inflexible and sickle-shaped, which can obstruct blood flow.

What is a sickle cell crisis?

A sickle cell crisis is a painful episode caused by blockages in blood vessels due to the sickle-shaped red blood cells, preventing oxygen and glucose from reaching cells, and can last from minutes to weeks.

How can sickle cell anemia be inherited?

Sickle cell anemia is inherited when an individual has two copies of the faulty, recessive allele. People with one copy are carriers and have a mix of normal and abnormal hemoglobin.

What is the significance of a Punnett square in understanding inheritance of sickle cell anemia?

A Punnett square can be used to predict the possible genotypes of offspring when both parents are carriers of the sickle cell trait, showing the chances of having children with the disorder, as carriers, or unaffected.

How many people are affected by sickle cell anemia worldwide?

Approximately 4.4 million people worldwide have sickle cell anemia, and an additional 43 million are carriers.

Why is sickle cell anemia more common in certain regions of the world?

Sickle cell anemia is more common in regions such as Central Africa, parts of India, the Middle East, and among people of African origin in other parts of the world, which also have a high prevalence of malaria.

How does the sickle cell allele provide protection against malaria?

The sickle cell allele offers protection against malaria by causing the red blood cells of carriers to be more fragile, often bursting when invaded by the malaria parasite, thus killing the parasite and interrupting its life cycle.

What is the relationship between the prevalence of sickle cell anemia and malaria?

The prevalence of sickle cell anemia is higher in regions affected by malaria because the sickle cell allele, while causing the disorder, also provides a survival advantage against malaria, leading to a higher likelihood of the allele being passed on.

How can individuals learn more about sickle cell anemia and related topics?

Individuals can learn more about sickle cell anemia and related topics through educational videos, subscribing to relevant channels, using educational apps like Few School, and asking questions in the comment sections of these platforms.