The X chromosome contains many genes that are not present on the Y chromosome. Females inherit one X chromosome from each parent. Males inherit the X chromosome from their mothers and the Y chromosome from their fathers. Males have one X and one Y chromosome (XY) and females have two X chromosomes (XX). These genes are located on the X chromosome. This change or mutation can prevent the clotting protein from working properly or to be missing altogether. Hemophilia is caused by a mutation or change, in one of the genes, that provides instructions for making the clotting factor proteins needed to form a blood clot. This condition often resolves with appropriate treatment. The majority of cases involve middle-aged or elderly people, or young women who have recently given birth or are in the later stages of pregnancy. In rare cases, a person can develop hemophilia later in life. The lower the amount of the factor, the more likely it is that bleeding will occur which can lead to serious health problems. The severity of hemophilia that a person has is determined by the amount of factor in the blood.

People with hemophilia have low levels of either factor VIII (8) or factor IX (9).

This can lead to spontaneous bleeding as well as bleeding following injuries or surgery. Blood contains many proteins called clotting factors that can help to stop bleeding. Hemophilia is usually an inherited bleeding disorder in which the blood does not clot properly.

What chromosomes occurs with scids