DNA sequencing using the SOLiD technique identified a T to C transition at position 4861 of the Vwf transcript in exon 28 of 52 total exons. Multiple transcripts of the Vwfgene are displayed on Ensembl and Vega. The mutated nucleotide causes a tyrosine to histidine substitution at amino acid 1542 of the encoded protein (Uniprot Q8CIZ8). The mutation has been confirmed by DNA sequencing using the Sanger method (see trace files for B5639 ).

The Vwf gene encodes encodes von Willebrand factor (VWF), a large multimeric glycoprotein that plays a central role in the blood coagulation system, serving both as a major mediator of platelet-vessel wall interaction and platelet adhesion, and as a carrier for coagulation factor VIII.  VWF is a heavily glycosylated, secreted protein that can form multimeric complexes partially due to intrachain and interchain disulfide bonds. The protein contains a CTCK (C-terminal cystine knot-like) domain, a pacifastin repeat, 4 TIL (trypsin inhibitory-like) domains, 3 VWFA domains, 3 VWFC domains,and 4 VWFD domains. Many of these domains function to provide binding sites for adhesion molecules or other proteins (Uniprot Q8CIZ8). Homozygous null mutants exhibit hemostatic and thrombotic defects similar to human von Willebrand disease. Mutants have prolonged bleeding time, newborns occasionally show fatal intra-abdominal bleeding and some adults have detectable fecal occult blood. Mutations of this gene in humans cause von Willebrand disease (VWD; OMIM 193400), a common and complex hereditary bleeding disorder.

The Y1542H change is located in the 2^nd VWFA domain, and is predicted to be probably damaging by the PolyPhen program.