_:vb50938902 "A primary polycythemia that has_material_basis_in homozygous or compound heterozygous mutation in the VHL gene (608537) on chromosome 3p25."^^ . _:vb50938902 . _:vb50938902 . _:vb50938902 . _:vb50938902 . _:vb50938902 "url:https://www.ncbi.nlm.nih.gov/pubmed/15725900"^^ . _:vb50938902 .