The ECM factors latent-transforming growth factor beta-binding protein 2 (LTBP2), periostin (POSTN) and versican (VCAN) were also found recently to be regulated in RV heart biopsies from patients suffering from pulmonary arterial hypertension (PAH), providing independent support of our results at the protein level in humans. The gene discussed is MMRN1; the disease is pulmonary arterial hypertension.