We previously used target region sequencing (TRS) of genes associated with vascular activity in PPHN patients, and we found a significant association between the disease and a variant of the EDN1 endothelin 1-coding gene [9], recently, we screened clinically relevant mutations in children with PPHN patients through a target panel containing more than 2700 rare disease-related genes [10]. This evidence concerns the gene EDN1 and persistent fetal circulation syndrome.