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Parents FAQ 1 | Parents
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Q. What is hemophilia?
A. Hemophilia is an inherited
disorder in which one of the proteins needed to form blood clots is missing
or reduced. There can also be a spontaneous mutation whereby there is no
family history of the disorder. The most common type of hemophilia, is factor
VIII (8) deficiency, also called hemophilia A or classic hemophilia. The
second most common type is factor IX (9) deficiency, also called hemophilia
B or Christmas disease (named for Stephen Christmas, the first person diagnosed
with factor IX deficiency).
Q. What are the symptoms of hemophilia?
A. When a person
with hemophilia is injured, he does not bleed harder or faster than a person
without hemophilia, he bleeds longer. Small cuts or surface bruises are
usually not a problem, but more traumatic injuries may result in serious
problems and potential disability (called "bleeding episodes").
There are different levels of hemophilia: mild, moderate, and severe:
People with mild hemophilia
(6% to 49% factor level) usually have problems with bleeding only after
serious injury, trauma, or surgery. In many cases, mild hemophilia is not
discovered until an injury or surgery or tooth extraction results in unusual
bleeding. The first episode may not occur until adulthood. The NHF publication
Mild Hemophilia explains symptoms and treatment for those with infrequent
People with moderate
hemophilia, about 15% of the hemophilia population, tend to have bleeding
episodes after injuries. They may also experience occasional bleeding episodes
without obvious cause. These are called "spontaneous bleeding episodes."
with severe hemophilia, about 60% of the hemophilia population, have bleeding
following an injury and may have frequent spontaneous bleeding episodes,
often into the joints and muscles.
Q. How common is hemophilia?
A. Approximately one in 5,000
males born in the United States has hemophilia. All races and economic groups
are affected equally.
Q. What causes hemophilia?
A. Everyone inherits two sex
chromosomes, X and Y, from his or her parents. A female inherits one X chromosome
from her mother and one X chromosome from her father (XX). A male inherits
one X chromosome from his mother and one Y chromosome from his father (XY).
The gene that causes hemophilia is located on the X chromosome.
If a mother contributes an X chromosome with the gene for hemophilia, and
the father contributes a Y chromosome, their child will be a boy born with
If a mother contributes an X chromosome with the gene for hemophilia, and
the father contributes an X chromosome without the gene for hemophilia,
their child will be a girl who is called a "carrier." She will not have
hemophilia, but she can pass it on to her male children.
A woman who gives birth to a child with hemophilia often has other male
relatives who also have hemophilia. Sometimes, a baby will be born with
hemophilia when there is no known family history. This means either that
the gene has been "hidden" (that is, passed down through several generations
of female carriers without affecting any male members of the family) or
the change in the X chromosome is new (a "spontaneous mutation"). This
occurs in approximately one-third of the cases of hemophilia.
It is very rare for a girl to be born with hemophilia, but it can happen
if the father has hemophilia and the mother is a carrier or if there are
two spontaneous mutations. For more information about women with bleeding
disorders, see the NHF publication, "A Guide for Women and Girls with Bleeding
Disorders." More information about the causes of hemophilia is available
in the NHF brochure, "Inheritance of Hemophilia."
Q. If we have more children, will
they also have hemophilia?
A. There's a chance one or
more of them will. There are four possible outcomes for the baby of a woman
who is a carrier (that is, who has one X chromosome without the hemophilia
gene and one X chromosome with the hemophilia gene) assuming the father
does not have hemophilia. These four possibilities are repeated for each
and every pregnancy:
1. A girl who is not a carrier
2. A girl who is a carrier
3. A boy without hemophilia
4. A boy with hemophilia
With each pregnancy, a woman who is a carrier has a 25% chance of having
a son with hemophilia.
Because the father's X chromosome determines the baby will be a girl, all
the daughters of a man with hemophilia will be carriers. None of his sons,
which is determined by the father through his Y chromosome, will have hemophilia.
To receive more information about carrier status and tests that are performed
call NHF and request the publication, "Inheritance of Hemophilia."
Genetic counseling is available at most HTCs. These professionals have information
to help you make family planning decisions.
If you have one child diagnosed with hemophilia, and you are expecting another
child, it is important for your obstetrician to know that you are at risk
for having another child with hemophilia. Also, some carriers may have lower
than normal blood clotting activity. A hematologist (doctor who specializes
in disorders of the blood) can talk with your obstetrician or midwife to
plan for a safe delivery. Some families with a history of hemophilia request
prenatal (before birth) testing to see if the fetus is affected. This testing
can be done early in the pregnancy, allowing the family to plan for a high-risk
delivery or to choose to end the pregnancy.
If you do not want prenatal testing, arrange for blood to be drawn from
the baby as soon as possible after birth. Tests to check for hemophilia
can be run on blood from the umbilical cord. The tests will tell whether
the baby has hemophilia; it does not test for the level of hemophilia (mild,
moderate, or severe). You will be advised to delay some procedures, such
as circumcision, until after you learn whether your son has hemophilia.
Can hemophilia be cured?
A. Not yet, but new developments
may make a cure possible in the next five to ten years. Technically, hemophilia
can be cured through a liver transplant but the risks involved in the surgery
and the requirement for lifelong medications to prevent rejection of the
new liver may outweigh the benefits. Researchers are working on a way to
insert factor VIII or factor IX genes into the cells of people with hemophilia
so their blood will clot more effectively. People treated with this gene
therapy would have few or no bleeding episodes. Put simply, gene therapy
has the promise to make the hemophilia more mild. Gene therapy does not
correct the affected factor VIII gene on the male's chromosome. Therefore,
all the daughters of a man with hemophilia even if he one day is treated
with gene therapy, will still be carriers.
As of the date of this publication, some types of gene therapy are being
tested in humans, but they are not available for general use. For more information,
call NHF's toll free information number (1-800-42-HANDI) for a packet of
information about gene therapy for hemophilia.
The information contained on the NHF web site is provided for your general
information only. NHF does not give medical advice or engage in the practice
of medicine. NHF under no circumstances recommends particular treatment
for specific individuals and in all cases recommends that you consult your
physician or local treatment center before pursuing any course of treatment.
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