Question

Why is haemophilia rare in females?

Answer 1

Hemophilia:

1. It is a genetically inherited disease where the body is unable to stop the flow of blood.
2. It is an X-linked disease, where an infected individual will continue to bleed even from a minor cut since the patient does not possess the natural phenomenon of blood clotting.
3. It is mainly due to the absence of antihemophilic globulin or factor VIII (hemophilia – A) and plasma thromboplastin factor IX.
4. As it is an X-linked disease it is more common in males and rare in females.
5. This is because females have two copies of the X chromosome and the heterozygous females for the gene are carriers of the disease.
6. Therefore for a female to be hemophilic, she should have two copies of the defective gene.
7. Her father should be hemophilic and the mother should at least be a carrier.
8. Whereas, Men have only one copy of the X chromosome and get the disease with only a single defective gene.
9. Men have only one copy of the X chromosome and get the disease with only a single defective gene.