Structure

The Structure of Factor VIII

As previously mentioned in the “Understanding Hemophilia section,” Factor VIII is very important to the blood clotting process (more specifically in the clotting cascade). The defect or deficiency of Factor VIII causes Hemophilia A. Factor VIII has a very complex structure, that is difficult to visualize. This page will try to explain the structure of Factor VIII , but is otherwise unnecessary to know in order to understand Hemophilia A's basics. To skip this section, go to the symptoms page.

This ribbon model represents the structure of Factor VIII in a hemophiliac. The dark purple spheres represent the severely mutated areas of the clotting factor. Picture originally from the Fred Hutchinson Cancer Research Center.

Factor VIII is a complex plasma glycoprotein, meaning it is a protein that circulates in our plasma. This clotting factor is made of 2,351 amino acids (the building blocks of protein), and is one of the largest and least stable coagulation factors. Factor VIII has a half life of around twelve hours in adults, and is even shorter in children.

Without Factor VIII, the coagulation cascade is incomplete. The absence of Factor VIII in the coagulation cascade is often compared to a set of dominoes, where each piece is needed in order to make all of the dominoes fall.

 

Sources for this page:

• Bolton-Maggs, Paul H B, K John Pasi. "Haemophilias A and B." The Lancet Vol 361(2003): 1801-1809.