HoG Handbook

Gene Modifiers


How frequently bleeding occurs in a person with a bleeding disorder is not determined just by one gene.  Other genes can affect the way factor is made and used in the body.  These other genes are called modifiers.  The modifiers can make a person have worse bleeding problems.  They can also make a person have less bleeding.  Children may inherit the same bleeding disorder gene from their parents but have very different symptoms.  This is because their modifying genes are different.