The proposed pathophysiological mechanism of PSIS is mutation in the genes (PIT1, PROP1, LHX3/LHX4, PROKR2, OTX2, TGIF, HESX1,[7] ROBO1,[8] and GPR161[9]) involved in the development of the anterior pituitary. The gene discussed is LHX4; the disease is pituitary stalk interruption syndrome.