Familial primary pulmonary hypertension (FPPH) is a well described clinical entity in which the disease occurs in at least two first degree relatives. It is clinically and pathologically indistinguishable from sporadic PPH. Mutations in the gene which encodes bone morphogenetic receptor 2 have recently been discovered in familial and sporadic PPH. This review discusses the basic clinical and genetic features of FPPH, and describes the research that led to the discovery of the disease-causing gene. Potential mechanisms of disease are also discussed, as well as implications for future investigations.