Proposed mechanism by which a T to G mutation at −61 results in the absence of factor VII protein. The diagrams depict the proximal promoter region for the factor VII gene of the wild-type sequence (top) and mutant sequence (bottom) in a patient with severe factor VII deficiency. A mutation at nucleotide −61 disrupts binding of the transcription factor HNF-4 to its cognate binding site located directly 5′ to the major transcription start site at −51 before the translation start site (+1).