A homozygous frameshift mutation results in premature termination of VWF protein synthesis. Genomic DNA obtained from normal and VWD dogs was sequenced, and the 2 sequences were compared, including sequence from exon 4, intron 4, and exon 5. The protein sequence is shown above the corresponding nucleic acid sequence with normal canine sequence shown in bold font above the VWD canine sequence. A single nucleotide deletion was found in the VWD canine sequence at base pair 255 as highlighted in the box, resulting in a frameshift. The altered VWD canine protein sequence is shown in italics. The altered VWD canine nucleotide sequence results in a stop codon at base pair 359 in exon 5.