In most affected families, the hemophilia gene has been present for many generations. Occasionally, however, a new mutation arises, and hemophilia appears for the first time with the birth of a baby. About one out of every three persons with hemophilia has no family history of the disorder. However, in most cases the hemophilia gene was carried by one or more previous generations. In some families, the abnormal gene may have only been passed on to females and so remained undetected.
Proteins occur in all animal and vegetable matter and are necessary for growth and repair.