Research on the molecular basis of PAH caused by BMPR-II mutations is beginning to yield novel approaches to therapy, for example, small molecule inhibitors of ALK-5. Enhancement of BMP signalling may be possible with BMP-derived ligands or rescue of BMPR-II cell surface expression for some mutations. For mutations leading to nonsense mediated mRNA decay, approaches aimed at transcript stabilisation provide another possible intervention. To further our genetic understanding of this rare disease, large international collaborative studies are needed to generate the numbers of patients necessary to undertake meaningful genome wide association studies for novel susceptibility genes or disease modifying genes. In addition, to provide accurate information to families, longitudinal cohort studies, coupled with biomarker studies, are required of affected and unaffected individuals in families segregating BMPR-II mutations.