Predescu et al. (31) found that EHBP1 was involved in the proliferative effect of EHIRSN on endothelial cells by changing the subcellular localization of EHBP1. The unexpected occurrence of PAH based on an atrial septal defect in our case may be due to a copy number gain of the EHBP1 gene that promotes EHBP1 expression in endothelial cells and diverts physiological vesicle trafficking to an alternative endocytic pathway, ultimately leading to molecular phenotypes of dysfunctional pulmonary vascular endothelial cells. The gene discussed is EHBP1; the disease is atrial septal defect.