What is Hemophilia?

Hemophilia is a group of inherited blood disorders in which the blood does not clot properly.

Hemophilia is the standard international spelling, also known as haemophilia in the UK, other translations include: hémophilie, hemofilie, hemofili, hemofilia, hämophilie, emofilia. We will use the standard international spelling for the purpose of this section.

Bleeding disorders are due to defects in the blood vessels, the coagulation mechanism, or the blood platelets. An affected individual may bleed spontaneously or for longer than a healthy person after injury or surgery.

The blood coagulation mechanism is a process which transforms the blood from a liquid into a solid, and involves several different clotting factors. The mechanism generates fibrin when it is activated, which together with the platelet plug, stops the bleeding.

When coagulation factors are missing or deficient the blood does not clot properly and bleeding continues.

Patients with Hemophilia A or B have a genetic defect which results in a deficiency in one of the blood clotting factors.

Queen Victoria was a carrier and passed the mutation to her son Leopold, and through several of her daughters to members of the royal families of Spain, Russia, and Germany.

Tsarevich Alexei Nikolaevich, son of Nicholas II (Russia) suffered from hemophilia and was a descendant of Queen Victoria - Rasputin was successful in treating his hemophilia, it was claimed.

Types of Hemophilia

Hemophilia A and Hemophilia B

There are two main types of hemophilia - Hemophilia A (due to factor VIII deficiency) and Hemophilia B (due to factor IX deficiency). They are clinically almost identical and are associated with spontaneous bleeding into joints and muscles and internal or external bleeding after injury or surgery.

After repeated bleeding episodes permanent damage may be caused to the joints and muscles that have been affected, particularly the ankles, knees and elbows.

Approximately 1 in 5,000 males is born with Hemophilia A, and 1 in 30,000 males is born with Hemophilia B. Hemophilia affects people of all races and ethnic origins globally. The conditions are both X-linked and virtually all sufferers of hemophilia are males. Female carriers may also bleed abnormally, because some have low levels of the relevant clotting factor.

People with hemophilia have a genetic mutation in the affected gene on the X chromosome, which results in reduced production of Factor VIII or IX and creates a bleeding tendency, because coagulation takes much longer than normal, thus making the clot weak and unstable

Approximately one third of patients with hemophilia have no family history of the disease, either because of new genetic mutations, or because previous affected generations either had daughters (who were carriers) or sons who died in early childhood from hemophilia or any other cause or who were not affected.

Acquired hemophilia

This is very rare. The patient develops the condition during his/her lifetime and it does not have a genetic or heritable cause. It occurs when the body forms antibodies that attack one or more blood clotting factors, (usually factor VIII), thus preventing the blood clotting mechanism from working properly. Patients may be male or female and the pattern of bleeding is rather different from that of classical hemophilia, the joints being rarely affected. The disorder is particularly associated with old age and occasionally complicates pregnancy.

What Causes Hemophilia ?

People with hemophilia are born with it. It is caused by a fault in one of the genes that determine how the body makes blood clotting factor VIII or IX. These genes are located on the X chromosome.

To understand how hemophilia is inherited, it is important to learn about chromosomes.

What are Chromosomes ?

Chromosomes are blocks of DNA (deoxyribonucleic acid). They contain very detailed and specific instructions that determine:

• How the cells in a baby's body develop.
• What features the baby will have, including, for example, hair and eye color.
• Whether the baby is male or female.

In humans there are 23 pairs of chromosomes, including the sex chromosome pair. There are two types of sex chromosome:

• The X chromosome
• The Y chromosome

All humans have a pair of sex chromosomes:

• Males have an X + Y pair
• Females have an X + X pair
NB  Females do not have any Y chromosomes.

What chromosomes do we inherit from our parents?

• A Male inherits his
  
  • X chromosome from his mother
  • Y chromosome from his father
• A Female inherits
  
  • One X chromosome from her mother
  • One X chromosome from her father
  She does not inherit both X chromosomes from her mother. She has no Y chromosomes.

Hemophilia Symptoms and Diagnosis

what are the symptoms of hemophilia ?

Hemophilia symptoms vary, depending on the degree of blood clotting factor (coagulation factor) deficiency and they also depend on the nature of any injury.

Three levels of hemophilia are recognized, according to the level of clotting factor amounts in the blood. These are often expressed as percentages of normal:

• Above 5% - mild hemophilia
• 1% to 5% - moderate hemophilia
• Less than 1% - severe hemophilia

Mild hemophilia

People with inherited mild hemophilia may not have any symptoms until an event occurs which wounds the skin or tissue, such as a dental procedure or surgery, and results in prolonged bleeding. In societies where male circumcision is carried out soon after birth, mild hemophilia will be detected earlier. Joint bleeding is uncommon.

Moderate hemophilia

Those with inherited moderate hemophilia will be noticeable early on. The child will bruise easily and may also experience internal bleeding symptoms, especially around the joints, and after a blow or a fall. Bleeding that occurs inside a joint is usually referred to as a joint bleed.

Symptoms of a joint bleed:

• Tingling sensation in the joint
• Pain in the joint
• Irritation in the joint

If left untreated, the patient may eventually experience:

• More severe pain in the joint
• Joint stiffness
• The affected area becomes swollen, tender and hot

Joint bleeds most commonly affect the:

• Ankles
• Knees
• Elbows
   ...and may less commonly affect the shoulders, hips or other joints.

Any surgical intervention, circumcision, dental procedure or injury will result in prolonged bleeding in a person with hemophilia.  

References:

 Medical News