hemophilia
Meaning of hemophilia: Bleeding is not faster than usual, only harder to stop, because the clot that forms is too fragile to hold.
Definition of hemophilia
Hemophilia is a bleeding disorder in which the blood cannot form a stable clot because one of the proteins in the clotting sequence, known as a clotting factor, is missing or present in reduced amounts. Bleeding after injury or surgery is prolonged, and in more severe forms bleeding occurs into joints and muscles without any obvious injury.
How hemophilia is built
- hem/o, hemat/o Combining form · Greek blood
- -philia Suffix · Greek attraction to, affinity for
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
Why does a missing factor matter so much?
Stopping a bleed happens in two stages. Platelets arrive within seconds and form a soft plug, which is why a small cut still stops bleeding in hemophilia. The plug then has to be reinforced by a mesh of fibrin, produced by a chain of clotting factors that activate one another in sequence. Remove one link and the chain stalls, so the blood clot that forms is weak and breaks down. The visible consequence is not faster bleeding but bleeding that restarts or continues, and internal bleeding into a joint that can damage cartilage over repeated episodes.
What are the types?
| Type | Factor affected | Inheritance |
|---|---|---|
| Hemophilia A | Factor VIII | X-linked; the commoner of the two |
| Hemophilia B | Factor IX | X-linked; also called Christmas disease |
| Hemophilia C | Factor XI | Autosomal; affects both sexes equally and is usually milder |
Hemophilia A and B look alike in the clinic, so the two are separated by laboratory measurement of factor activity rather than by symptoms. Severity tracks how much factor activity remains: a trace produces frequent spontaneous bleeding, while a partial deficiency may only show itself after surgery or a significant injury.
How is it inherited?
The genes for factors VIII and IX sit on the X chromosome. Someone with one X and one Y has no second copy to compensate, so a faulty gene produces the condition, while someone with two X chromosomes usually has a working copy on the other. That is why hemophilia A and B appear far more often in males. The older picture of female relatives as unaffected carriers is now known to be incomplete, since a proportion have reduced factor activity themselves and bleed accordingly. A first case in a family can also arise from a new genetic change with no previous family history, and genetic testing is used to identify the specific alteration. A separate acquired form exists in which the immune system produces antibodies against a person's own clotting factor.
Also known as
Used in a sentence
The child's family history of hemophilia prompted early laboratory testing of clotting factor levels.
Good to know
Hemophilia A and hemophilia B present similarly and are separated by measuring which clotting factor is deficient, a distinction that matters for laboratory testing and for factor replacement rather than for symptoms.
Word origin
Where “hemophilia” comes from
Formed from hemo-, from Greek haima, meaning blood, and -philia, from Greek philia, meaning a tendency toward something.