Factor VIII (FVIII) is an essential blood clotting factor. In humans, Factor VIII is encoded by the F8 gene . [ 1 ] [ 2 ] Defects in this gene results in hemophilia A , a common recessive X-linked coagulation disorder. more

Factor VIII (FVIII) is an essential blood clotting factor. In humans, Factor VIII is encoded by the F8 gene . [ 1 ] [ 2 ] Defects in this gene results in hemophilia A , a common recessive X-linked coagulation disorder. [ 3 ]

Factor VIII participates in blood coagulation ; it is a cofactor for factor IXa which, in the presence of Ca +2 and phospholipids forms a complex that converts factor X to the activated form Xa. The Factor VIII gene produces two alternatively spliced transcripts. Transcript variant 1 encodes a large glycoprotein , isoform a, which circulates in plasma and associates with von Willebrand factor in a noncovalent complex. This protein undergoes multiple cleavage events. Transcript variant 2 encodes a putative small protein, isoform b, which consists primarily of the phospholipid binding domain of factor VIIIc. This binding domain is essential for coagulant activity. [ 4 ] less