We study the genetics of human blood clotting disorders using zebrafish and have developed models of coagulation factor deficiency through genome editing with TALENs and CRISPR. Sensitized ethylnitrosourea (ENU) mutagenesis and high throughput chemical suppressor screens are being performed on mutants with pathologic bleeding and clotting phenotypes. This strategy will identify genetic modifiers and novel molecules with the potential to improve the diagnostic and therapeutic tools available for treatment of affected patients.