Sickle Cell Anaemia

Question 1

What are 3 symptoms of sickle cell anaemia?

Answer 1

1. Fatigue.
2. High blood pressure.
3. Heart failure.

Question 2

Explain how sick cell causes complication like a stroke.

Answer 2

The sickle-shaped red blood cells often die early resulting in anaemia. They are also inflexible and can become stuck in blood vessels causing a blockage. This can lead to a clot forming and moving towards the brain causing a stroke.

Question 3

How is sickle cell anaemia inherited? Describe the genotype and phenotype of those with sickle cell and carriers?

Answer 3

The condition is inherited in an autosomal receive pattern which means both copies of the gene in each cell have mutations. Carriers show no ill effects unless oxygen is in short supply. If this occurs red blood cells show mild sickling.

Question 4

Name and describe the type of mutation and what effect does this mutation have on the protein produced?

Answer 4

Due to a point mutation. Point mutations are changes in a single base usually during DNA replication. The different base sequence means valine amino acid is added instead of glutamic acid. This results in a different from of protein, altering the haemoglobin produced and the shape of red blood cells.

Question 5

The genes of individuals with sickle cell anaemia code for “haemoglobin S”. What is haemoglobin S and how does it affect red blood cells?

Answer 5

Haemoglobin S is an inherited variant of normal adult haemoglobin. It can cause red blood cells to misshapen and breakdown.

Question 6

What is the mortality rate of sickle cell anaemia?

Answer 6

Ages 0-3: 68%
Ages 4-9: 39%
Ages 10-14: 24%

Question 7

How has the mortality rate improved overtime?

Answer 7

Through the introduction of a vaccine that protects against pneumococcal disease.