GENETIC BASIS OF HEMOPHILIA

“A group of hereditary genetic disorder  that impair the body's ability to control blood clotting or coagulation, which is used to stop bleeding when a blood vessel is broken.”

In the whole history of hemophilia, the Jews were first to recognize it. The hemophilia blood disorder became known as the royal disease because Queen Victoria was a carrier.

Hemophilia

Hemophilia A - Classic Hemophilia orFactor VIII deficiency (80%

cases) Haemophilia B - Christmas Disease or

Factor IX deficiency (20% cases)

Haemophilia C – Acquired Hemophilia or coagulant factor XI deficiency (very rare)

Main types of haemophilia

Characteristic symptoms vary with severity. 

Deep internal bleeding Easy bruising Joint damage Transfusion transmitted infection

Major signs and symptoms

Hemophilia is an inherited X-linked genetic disorder.

Our bodies have 12 clotting factors that work together in blood clotting and they are present on X chromosome. Having too little of factors VIII,IX or XI cause hemophilia.

A person with hemophilia will only lack one factor not the three.

Genetics of Hemophilia

A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. It is inherited in zig-zag manner.

A male is “affected” if he has the abnormal gene on his X-chromosome.

A female is a “carrier” of hemophilia if she has the abnormal gene on one of her X chromosomes. Even though she doesn’t have the condition, she can pass the gene on to her children.

1. Carrier Mother + Non-hemophiliac Father

When a carrier Mother and an unaffected Father create a child, each pregnancy has a 25% chance of resulting in a female non-carrier, a 25% chance of a female carrier, a 25% chance of non-hemophiliac male, and a 25% chance of a male with hemophilia.

Different Cases

2. Non-carrier Mother + Father With Hemophilia

Each pregnancy has a 50% chance of a female carrier and a 50% chance of a non-hemophiliac male. Sons of hemophiliac fathers and non-carrier mothers will not have hemophilia.

3. Carrier Mother + Father With Hemophilia

Each pregnancy has a 25% chance of a female carrier, a 25% chance of a female with hemophilia, a 25% chance of a non-hemophiliac male, and a 25% chance of a male with hemophilia.

4. Mother With Hemophilia + Father With Hemophilia

Each pregnancy has a 50% chance of resulting in a female with hemophilia and a 50% chance of resulting in a male with hemophilia.

5. Mother With Hemophilia + Non-hemophiliac Father

Each pregnancy has a 50% chance of resulting in a female carrier and a 50% chance of resulting in a male with hemophilia.

Knowledge of genetics lets us make the following statements about hemophilia:

Very rarely, a girl is born with hemophilia. This can happen if her father has hemophilia and her mother is a carrier.

Females who are carriers usually have enough clotting factors from their one normal X chromosome to prevent serious bleeding problems.

Some males with the disorder are born to mothers who aren’t carriers. In these cases, a mutation (random change) occurs in the gene.

Different types of hemophilia are classified into:

Mild Hemophilia 5 – 30 % Normal Factor

Moderate Hemophilia

1 – 5% Normal Factor Severe Hemophilia

<1% Normal factor

Hemophilia is quite rare, with only about 1 instance in every 10,000 births (or 1 in 5,001 male births) for hemophilia A and 1 in 50,000 births for hemophilia B.

Occurence

Hemophilia isn’t curable , but treatment can prevent crippling deformities and prolong life expectancy. Correct treatment quickly stops bleeding by increasing plasma levels of the deficient clotting factor. This helps to prevent disabling deformities due to repeated bleeding into muscles and joints .

MANAGMENT