Features include always present findings: Increased circulating hemoglobin concentration, Increased hematocrit, Deep venous thrombosis, and Elevated circulating erythropoietin concentration and others; and common findings: Pruritus. 7 total HPO annotations.

EPAS1 encodes endothelial PAS domain protein 1 (870 aa). Transcription factor involved in the induction of oxygen regulated genes. Highest expression in Lung (1,031 TPM) and Artery Tibial (566.5 TPM).

Erythrocytosis, familial, 4 is associated with mutations in the EPAS1 gene on chromosome 2.

The EPAS1 protein participates in Expression of EPAS1 (HIF2A), Nuclear PHD1,3 hydroxylates proline residues on EPAS1 (HIF2A), and Cytosolic PHD2,3 hydroxylates proline residues on EPAS1 (HIF2A) pathways.

EPAS1 is classified as a druggable target (Druggable Genome, Kinase, Transcription Factor, and Transcription Factor Complex categories) with score 8.7.

Genetic testing for EPAS1 is available. Testing is considered confirmatory for diagnosis.

Biomarker and diagnostic research for erythrocytosis, familial, 4 has been reported in the published literature.

Phenotype severity distribution: 5 always present features, 1 common feature.

No clinical trials have been registered for erythrocytosis, familial, 4.

14 publications have been identified in PubMed for erythrocytosis, familial, 4. Research spans Case Report / Case Series (36%), Clinical Trial Publication (21%), and Review / Meta-Analysis (14%).