This is the most common and mildest form of VWD, in which a person has lower than normal levels of VWF. A person with Type 1 VWD also might have low levels of factor VIII, another type of blood-clotting protein. This should not be confused with hemophilia, in which there are low levels or a complete lack of factor VIII but normal levels of VWF.
With this type of VWD, although the body makes normal amounts of the VWF, the factor does not work the way it should. Type 2 is further broken down into four subtypes―2A, 2B, 2M, and 2N―depending on the specific problem with the person’s VWF. Because the treatment is different for each type, it is important that a person know which subtype he or she has.
This is the most severe form of VWD, in which a person has very little or no VWF and low levels of factor VIII.
Source: Centers for Disease Control and Prevention