POU1F1 and hypopituitarism: There are also mutations associated with multiple pituitary hormone deficiencies, such as defects in transcription factors (mutations in HESX1, SOX 2/3, LHX3/4, PROP1, POU1F1 or PIT1, IGSF1), and in the enzyme prohormone convertase (PC1) [104,105,106,107].