Three uncharacterized genes were differentially expressed upon lung perfusion in PAH and IPF: Tigger Transposable Element-Derived protein 3 (TIGD3), a DNA-binding protein-coding gene (> 2.4 FC; p < 0.005), and ENSG00000262660 and ENSG00000262730, both of which were downregulated in PAH and upregulated in IPF. The gene discussed is TIGD3; the disease is pulmonary arterial hypertension.