Implications of Mutations of Activin Receptor-Like Kinase 1 Gene (<i>ALK1</i>) in Addition to Bone Morphogenetic Protein Receptor II Gene (<i>BMPR2</i>) in Children With Pulmonary Arterial Hypertension

Each proband with the ALK1 mutation developed PAH, as did the probands with the BMPR2 mutation. Hence, it is proposed that ALK1 plays as notable a role as BMPR2 in the etiology of PAH. Furthermore, asymptomatic carriers with the ALK1 mutation within the serine - threonine kinase domain are at risk of developing PAH and hereditary hemorrhagic telangiectasia, so close follow-up is recommended for those individuals.