Hemophilia and von Willebrand disease (vWD) are the most common inherited bleeding disorders. They are caused by a lack of a specific clotting factors needed to control bleeding. Hemophilia is an inherited X-linked genetic condition that primarily affects males. Von Willebrand disease is a genetic disorder affecting both men and women, caused by a genetic change on the twelfth chromosome.
Hemophilia is a genetic bleeding disorder that prevents the blood from clotting normally. Certain bleeding episodes, such as brain bleeding, may be life threatening. Hemophilia occurs primarily in males; however, a female may, on occasion, be affected. Woman who are carriers of hemophilia may have low factor VIII or IX activity, may be symptomatic and may be considered to have Hemophilia. They can often require the same factor replacement as males during trauma, surgery and child birth. All carriers of hemophilia should be tested before surgery and other medical procedures.
The two types of hemophilia are factor VIII deficiency, also known as hemophilia A, and factor IX deficiency (hemophilia B), or Christmas disease. The main symptom of hemophilia is uncontrolled bleeding, characteristically into muscles and joints. Repeated bleeding results in pain, swelling and, if left undertreated or untreated, causes permanent damage. There are three levels of severity: mild, moderate and severe. Individuals with mild hemophilia have prolonged bleeding usually only with surgery, tooth extraction, or major injuries. Individuals with moderate hemophilia may have internal bleeding into joints or muscles following relatively minor trauma, such as a sprain or hard fall. In severe hemophilia, bleeding episodes are more frequent. They can occur with no apparent injury or cause, in addition to prolonged bleeding with trauma and surgery. Bleeding can be as common as two or three times weekly for those severely affected and not on prophylactic therapy treatment. Frequent episodes are both painful and expensive.
While hemophilia is most commonly genetically inherited, approximately one third of all newly diagnosed cases occur in families with no prior history. Instead, the disorder results from a spontaneous genetic mutation. Hemophilia A, which accounts for 80% of all hemophilia patients, occurs in approximately 1 in 5,000 male births. Hemophilia B, accounts for 20% of all case and occurs in 1 out of every 10,000 male births. There are approximately 17,000 people with hemophilia in the United States. Of these, approximately 65% are classified as severe, 15% moderate, and 25% mild, depending upon the level of clotting factor (protein) found in their blood. The worldwide incidence of hemophilia is estimated at more than 400,000 people. Approximately 70% of people around the world do not have access to treatment. While treatment exists; it is costly and may require lifelong infusions of replacement clotting factor. Hemophilia is treated with blood and/or genetically engineered replacement therapies an can have an estimated cost for treatment at $300,000.00 yearly. Currently, there is no cure.
Von Willebrand disease is also a genetic bleeding disorder that prevents the blood from clotting normally. It is caused by a deficient or defective blood protein known as von Willebrand factor. Although less widely known than hemophilia, von Willebrand disease (vWD) is estimated to affect over two million people in the U.S., and as many as 1 in 100 people. VWD is a milder disorder with fewer and less severe symptoms, although a severe form can occur. Of the three main types, type 1 (the mildest form of the disease) accounts for 70% of cases. Both males and females can have von Willebrand disease. Symptoms include frequent nosebleeds, a tendency to bruise easily, and excessive bleeding following surgery. With severe vWD, joint bleeding much like hemophilia can occur.
In women, the disease may also cause heavy, prolonged bleeding during menstruation and excessive bleeding following childbirth. It is often undiagnosed or incorrectly attributed to a gynecologic condition. Testing is extremely complicated for a correct diagnosis, which will often lead to a missed diagnosis. Surveys conducted by the Center for Disease Control have shown that on an average, it takes 16 years for a woman with a bleeding disorder to be diagnosed from the onset of symptoms.
Rare Bleeding Disorders
Rare bleeding disorders are deficiencies in clotting factor I, II, V, VII, X, XI and XIII. In general, these rare bleeding disorders are passed down in an autosomal recessive fashion, which means they affect men and women equally. This also means that when the factor deficiency is inherited from only one parent, the child will be a carrier of the condition, though he or she will usually not have symptoms. New mutations may also appear; in these cases, the family history will be negative.