In recent studies, in addition to BMPR2, mutations in Activin A receptor type II-like kinase-1 (ACVRL1) and Familial Atrial fibrillation type 7 (ATFB7) genes, were shown to cause hereditary PAH and increase the severity of the disease [10,11]. This evidence concerns the gene ACVRL1 and pulmonary arterial hypertension.