von Willebrand's disease in Scandinavia and on difficulties in diagnosing von Willebrand's disease type I.

The research on von Willebrand's disease performed in Sweden and Finland since the late 1920s is reviewed. The difficulties in diagnosing mild von Willebrand's disease, due to intra-individual variability, is discussed in relation to making correct pedigrees for genetic studies. As shown by some examples, new techniques for genetic studies will eliminate such difficulties and lead to better understanding of the pathogenesis.