AAV vectors for the expression of FVIII forms. The schematic shows the F8 gene (encoding FVIII) expression plasmids used for the preparation of recombinant AAV vectors flanked by inverted terminal repeats (ITR). The human α1-antitrypsin (hAAT) promoter is linked to the hepatic locus control region (HCR) of a single copy of the apolipoprotein E (ApoE) enhancer. SV40 intronic and polyadenylation (poly A) sequences are from simian virus 40. Differences in the sequences used for the generation of FVIII-RH and FVIII-BDD are indicated. bp, base pairs.