Data and findings for selected family members. (A) Family tree. (B) Hematological parameters in selected family members. I-2 was diagnosed with “heart failure” at age 62; echocardiography was not available. *Not contemporaneous measurements. – indicates data not available. (C) Genome-wide linkage to autosomal dominant erythrocytosis. (D) Parametric LOD score at region circled in red in panel C. (E) Sequencing trace of showing G/A heterozygosity at base 2097, predicting a change from glycine to arginine at residue 537, 6 codons from critical hydroxyl acceptor proline (underlined). (F) HRE-Firefly:Renilla luciferase activity following cotransfection of a plasmid containing the coding sequence of HIF2α with or without mutations shown. Results shown are means plus or minus SD of 3 independent experiments, each performed in triplicate.