EDN1 and pulmonary arterial hypertension: None of the kits included genes that have been associated with PAH, such as AGTR1, TBX4, EDN1, EDNRA, NOS2, SERPINE, SIRT3, THBS1, TOPBP1, or TRCP6. For example, AGTR1 has been related to later age PAH at diagnosis [28], TBX4 has been related to childhood-onset of PAH [29], and EDN1, EDNRA, and NOS2 have been related to susceptibility to develop the disease and its clinical course as well as susceptibility to systemic sclerosis-related PAH [16, 30–32].