VWF and von Willebrand disease 1: Interestingly, the frequency of the minor allele (MAF) of rs7978987, which corresponded with higher VWF:Ag levels, was lower among our patients with type 1 VWD (MAF = 0.29) than reported by dbSNP (http://www.ncbi.nlm.nih.gov/projects/SNP/) (MAF = 0.38) and in the meta-analysis of the CHARGE consortium (MAF = 0.35) [4].