What is Haemophilia, Why it affects men more than women

• Hemophilia can be life threatening in cases when bleeding cannot be stopped for some reason or it occurs in the brain or some other vital organ.

About Haemophilia

It is a hereditary bleeding disorder that mainly affects men. In this condition, the blood clotting proteins are missing and one bleeds for longer than normal after an injury.

• Because of problems in clotting, hemophilia can be life threatening in cases when bleeding cannot be stopped for some reason or it occurs in the brain or some other vital organ.
• Bleeding in the head can lead to seizures or paralysis.

Causes of Haemophilia

When blood moves through blood vessels, it has a natural tendency to keep itself in fluid status but in case of injury to the vessels, there is a clot formation which prevents loss of blood.

• The clot formation is a complex process which involves clotting factors and platelets.
• When these clotting factors are missing due to mostly genetic reasons this disease occurs.
• Hemophilia can be acquired too in case of certain conditions when a person's immune system attacks clotting factors in the blood.
• Pregnancy, autoimmune conditions, multiple sclerosis, cancer or drug reactions can cause it.

Symptoms of Haemophilia

Some are:

• Unexplained and excessive bleeding from cuts or injuries,
• Large or deep bruises,
• Unusual bleeding after vaccinations,
• Pain,
• Swelling or tightness in joints,
• Blood in urine or stool,
• Nosebleeds without a known cause.

Why Haemophilia is rare in women

Hemophilia is a X linked recessive disorder. It means the gene for hemophilia lies on the X chromosome.

• Since females have two X chromosomes, they are usually not affected by hemophilia.
• Women can be the carriers of the disease and pass on the disease to their sons.
• Since males have only one X chromosome, they can manifest the disease in the absence of a normal gene.

Lyonization of X chromosome

• There is inactivation of one of the X chromosomes with normal wild type gene and only the affected chromosome with hemophilia gene is expressed.

When both X chromosomes are affected

• The condition is called homozygosity.
• If the mother is carrier and father is affected with the disease, then the daughter can inherit both affected X chromosomes from each parent and will manifest the disease.
• Another reason could be De Novo mutation in the normal X chromosome , making both chromosomes having defective genes.

Turner syndrome

• In women affected by it, one of the X chromosomes is missing and in case the X chromosome is affected, they can manifest the disease.

Deficiency of vitamin K

• Vitamin K helps in activation of coagulation factors.
• Deficiency of Vitamin K also leads to hemophilia like state.

Exam Track

Prelims Takeaway

• Haemophilia: Causes and Symptoms
• Haemophilia: rare in women
• Lyonization of X chromosome
• Turner syndrome
• Deficiency of vitamin K

Mains Takeaway

Q. analyse the severity of the Haemophilia disease. Discuss various causes and symptoms of haemophilia.