The pituitary transcription factor Pit-1 is expressed during the later diff
erentiation stages of anterior pituitary development and Pit-1 mutations ha
ve 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 leavi
ng DNA binding capabilities unimpaired, decrease its function within the tr
ansactivation complex. Approximately half of all patients with this phenoty
pe do not show any defect within the Pit-1 gene. Prop-1, a recently discove
red transcription factor of anterior pituitary development, seemed a likely
candidate for such mutations. Prop-1 mutations, however, have been found s
o far to induce a combined pituitary hormone deficiency for GH, prolactin,
TSH and gonadotropins. We describe here a group of patients with isolated a
nd 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.