該基因編碼凝血因子viii，參與凝血的內在途徑；因子viii是因子ixa的輔因子，在ca+2和磷脂存在下，將因子x轉化為激活的x a。這個基因產生兩個交替剪接的轉錄本轉錄變體1編碼一種大的糖蛋白，亞型a，在血漿中循環，并與非共價復合物中的血管性血友病因子相關這種蛋白質經歷多重分裂事件。轉錄變異體2編碼一種假定的小蛋白，亞型b，主要由viiic因子的磷脂結合區組成。這個結合域是凝血活性所必需的。該基因缺陷導致血友病A，一種常見的隱性X連鎖凝血障礙。[由RefSeq提供，2008年7月]
This gene encodes coagulation factor VIII, which participates in the intrinsic pathway of blood coagulation; factor VIII is a cofactor for factor IXa which, in the presence of Ca+2 and phospholipids, converts factor X to the activated form Xa. This 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. Defects in this gene results in hemophilia A, a common recessive X-linked coagulation disorder. [provided by RefSeq, Jul 2008]