Question

Which condition is characterised by reduced clotting ability of blood?

• A. Leukaemia
• B. Haemophilia
• C. Polycythemia
• D. Atherosclerosis

Hint:

Haemophilia is often referred to as the "Royal Disease" because it was passed down through the royal families of Europe, starting with Queen Victoria of England, who was a carrier of the gene.
Since it is a sex-linked recessive disorder, it is much more common in males than in females.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
This question is from Biology, specifically human physiology and genetic disorders of the circulatory and coagulation systems.
The goal is to identify which condition is characterized by a reduced ability of the blood to clot.

Step 2: Key Concept or Approach:
Hemostasis is the physiological process that stops bleeding at the site of vascular injury. It requires platelets and plasma proteins called clotting factors.
A deficiency or defect in any of these clotting factors impairs the coagulation cascade, leading to prolonged bleeding, a condition classically exemplified by Haemophilia.

Step 3: Detailed Explanation:

• Haemophilia is a sex-linked recessive genetic disorder that impairs the body's ability to produce blood clots.

• Individuals with Haemophilia have a mutation in the genes located on the X chromosome that code for essential clotting factors.

• In Haemophilia A, there is a deficiency of clotting Factor VIII, while in Haemophilia B, there is a deficiency of clotting Factor IX.

• Due to the lack of these functional factors, the coagulation cascade is disrupted, preventing the formation of a stable fibrin mesh to seal broken blood vessels, leading to prolonged bleeding even from minor cuts.

• Let us analyze the other options to understand why they are incorrect:
- Leukaemia is a cancer of the blood-forming tissues, including bone marrow, characterized by the abnormal proliferation of white blood cells.
- Polycythemia is a condition in which there is an abnormal increase in the concentration of red blood cells, which thickens the blood.
- Atherosclerosis is a condition where arteries narrow and harden due to the accumulation of fatty plaques, obstructing normal blood flow.



Step 4: Final Answer:
The condition characterized by a reduced clotting ability of blood is Haemophilia, which corresponds to option (B).