Inherited Bleeding Disorders 101

Hemophilia A, also called factor VIII (8) deficiency or classic hemophilia, is a genetic disorder caused by missing or defective factor VIII (FVIII), a clotting protein. Although it is passed down from parents to children, about 1/3 of cases found have no previous family history.

According to the US Centers for Disease Control and Prevention (CDC), hemophilia occurs in approximately 1 in 5,617 live male births. There are between 30,000 – 33,000 males with hemophilia in the US. More than half of people diagnosed with hemophilia A have the severe form. Hemophilia A is four times as common as hemophilia B. All races and ethnic groups are affected, and women can and do have hemophilia and/or bleeding disorders. Despite long-standing misconceptions about bleeding disorders in women, women’s voices and experiences are now being taken more seriously.

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Hemophilia B, also called factor IX (FIX) deficiency or Christmas disease, is a genetic disorder caused by missing or defective factor IX, a clotting protein. Although it is passed down from parents to children, about 1/3 of cases are caused by a spontaneous mutation, a change in a gene.

According to the US Centers for Disease Control and Prevention, hemophilia occurs in approximately 1 in 5,000 live births. There are between 30,000 – 33,000 people with hemophilia in the US. All races and ethnic groups are affected. Hemophilia B is four times less common than hemophilia A.

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von Willebrand disease (VWD) is an inheritable bleeding disorder and people with VWD are either missing or low in the clotting protein von Willebrand factor (VWF) – or it doesn’t work as it’s supposed to. VWD is the most common bleeding disorder and occurs equally across all races and ethnicities affecting up to 1% of the US population – or approximately 1 in every 100 people. It occurs equally in men and women. However, women may be more symptomatic due to heavy menstrual bleeding. The guidelines for
VWD were updated in 2021. Click here to read the guidelines in full. To find out if you
have signs and symptoms of VWD go here.

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Platelet disorders occur when platelets—the blood cells responsible for binding together
to form a clot—do not function properly. Platelets are tiny, irregularly shaped cell
fragments that act as the body’s first line of defense during an injury. When a blood
vessel is damaged, platelets become ” sticky ” and cluster together to plug the site, while
simultaneously attracting the proteins necessary to build a stable, permanent clot.
There are several ways this process can fail: the body may produce too few platelets,
too many, or the platelets themselves may have a structural defect that prevents them
from sticking together. Because the mechanics of platelet signaling are highly complex,
some conditions are not yet fully understood, which may result in a diagnosis of an
“unspecified platelet disorder.”

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Rare Factor Deficiencies such as I, II, V, VII, X, XI, XII and XIII, are all rare disorders. Factor deficiencies are defined by which specific clotting protein in the blood protein is low, missing or doesn’t work properly. These very rare factor deficiencies were only identified within the last 60-70 years.

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