Factor VII G331D: a variant molecule involving replacement of a residue in the substrate-binding region of the catalytic domain

An individual identified as having a dysfunctional factor VII was studied to seek underlying genetic defects. A heterozygous mutation in the factor VII gene exon 8 was identified as substitution of A for G at nucleotide position 10,909 [Gly (GGC) to Asp (GAC)]. An abolished MspI restriction site was used to confirm heterozygosity for the defect. The mutation occurs within the substrate-binding pocket at a locus on the surface of the factor VII molecule containing a protein-protein interactive site for substrates, providing an explanation for the observed dysfunctional procoagulant activity.