<prompt> In primary pulmonary hypeension, basic abnormality in gene lies inBone morphogenic protein receptor IIEndothelinHomebox genePAX - 11  <response>: Decreased expression of the voltage-regulated potassium channel, mutations in the bone morphogenetic protein-2 receptor, increased tissue factor expression, overactivation of the serotonin transpoer, transcription factor activation of hypoxia-inducible factor-1 alpha, and activation of nuclear factor of activated T cells. As a result, there appears to be a loss of apoptosis of the smooth muscle cells that allow their proliferation and the emergence of apoptosis-resistant endothelial cells that can obliterate the vascular lumen.Ref: Harrisons 18e p2077 