Definition:

Primary pulmonary hypertension (PPH) is a progressive disease characterised by raised pulmonary vascular resistance, which results in diminished right-heart function due to increased right ventricular afterload. PPH occurs most commonly in young and middle-aged women; mean survival from onset of symptoms is 2-3 years. Mutations in the type II bone morphogenetic protein (BMP) receptor (BMPR)-II are now considered to be the genetic basis for familial PPH and ~30% of cases of sporadic PPH. BMPs are members of the transforming growth factor beta superfamily and affect intracellular signalling via Smads and mitogen-activated protein kinases. It has been shown that missense mutations of cysteine residues in the extracellular or kinase domain of BMPR2 result in intracellular localisation of the mutated receptor and negligible Smad signalling.