Abstract: The present disclosure relates to methods, systems, and compositions to repair one or more mutations in a Factor VIII gene sequence of a subject by introducing into a cell of the subject one or more polynucleotides encoding a DNA scission enzyme (DNA-SE) and one or more repair vehicles (RVs) containing at least a cDNA-repair sequence (RS) such that insertion of the cDNA-RS through homologous recombination with the F8 gene of the subject (sF8) provides a repaired F8 gene (rF8), the repaired F8 gene (rF8) upon expression forming a functional FVIII conferring improved coagulation functionality to the FVIII protein encoded by the sF8. The present disclosure also relates to cells derived using the methods, systems and compositions described.