Blood disorders can affect any of the three main components of blood:
Red blood cells, which carry oxygen to the body's tissues
White blood cells, which fight infections
Platelets, which help blood to clot
Blood disorders can also affect the liquid portion of blood, called plasma.
Treatments and prognosis for blood diseases vary, depending on the blood condition and its severity.
Hemophilia A -- also called classic hemophilia -- is most common and occurs in about 85% of people with hemophilia.
Hemophilia B -- also called Christmas disease -- is less common and occurs in about 15% of people with hemophilia.
Hemophilia A results from too little of a plasma protein called factor VIII, which helps blood clot. The greater the deficiency, the more severe the symptoms.
Mild hemophilia: 5% to 25% of the normal factor VIII level
Moderate hemophilia: 1% to 5% of the normal factor VIII level
Severe hemophilia: Less than 1% of the normal factor VIII level
Most people who have hemophilia A have moderate or severe symptoms.
Hemophilia B results from too little of a plasma protein called factor IX, which helps blood clot. As in hemophilia A, hemophilia B can be mild, moderate, or severe. The greater the deficiency, the more severe the symptoms.
If there is no family history of hemophilia, an infant would not be tested for the condition. However, if there is a family history of hemophilia, specific tests can be done from an umbilical cord blood sample to see if a newborn infant has hemophilia. In fact, if the family desires, such testing can be done before a child is born.
For moderate or severe hemophilia, doctors and caregivers usually don't see any signs of the condition at birth or even for some time afterward. Symptoms in children may include:
Heavy bleeding in a male baby after circumcision
Excessive bruising or unusual bleeding during teething
Swollen, bruised joints or muscles when learning to walk
Frequent falls and bumps
For mild hemophilia, you may not have any noticeable symptoms until you undergo a dental procedure, which may cause you to bleed heavily, or you may not have any unusual bleeding unless you are injured in an accident or have surgery.