To date, 16 distinct human Prophet of Pit-1 (Prop1) gene mutations have been identified in patients with CPHD, inducing a phenotype involving GH, follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin and thyroid-stimulating hormone (TSH), and rarely adrenocorticotropic hormone, deficiency.
The genetic abnormalities include mutations within: (1) Hesx1 (IGHD, SOD or CPHD); (2) Lhx3 (CPHD with preservation of cortisol secretion and a short stiff neck); (3) Lhx4 (GH, TSH and ACTH deficiency with cerebellar hypoplasia); (4) Prop1 (variable CPHD often associated with pituitary masses); (5) POU1F1 (GH, prolactin and TSH deficiency); (6) GHRHR (IGHD) and (7) GH1 (IGHD).
Mutations of the pituitary transcription factor Prop-1, which is responsible for the syndrome of Ames dwarfism in mice, are being increasingly recognized as a cause of combined pituitary hormone deficiency in humans, although ACTH deficiency has been described only once.