GH transcription factors.

The pituitary transcription factor Pit-1 is expressed during the later differentiation stages of anterior pituitary development and Pit-1 mutations have been identified as the cause of a combined pituitary hormone deficiency (CPHD) for GH, prolactin and TSH. Mutations within the human Pit-1 gene can either impair the DNA binding of this transcription factor, or while leaving DNA binding capabilities unimpaired, decrease its function within the transactivation complex. Approximately half of all patients with this phenotype do not show any defect within the Pit-1 gene. Prop-1, a recently discovered transcription factor of anterior pituitary development, seemed a likely candidate for such mutations. Prop-1 mutations, however, have been found so far to induce a combined pituitary hormone deficiency for GH, prolactin, TSH and gonadotropins. We describe here a group of patients with isolated and combined pituitary hormone deficiencies who were screened for Pit-1 and Prop-1 mutations to characterize the phenotypic spectrum of defects within these two genes.