THE GENETIC ORIGIN INCREASINGLY INCRIMINATED: Congenital pituitary hormone deficiencies represent conditions of hypopituitarism resulting from abnormal pituitary ontogenesis. This group of genetically determined diseases has considerably widened with the development of molecular biology. Many transcription factors playing a role in pituitary development have been identified, and their mutations reported as causes of isolated or multiple pituitary hormone deficiencies. Isolated pituitary hormone deficiencies may affect somatotroph, gonadotroph, and corticotroph lineages. They result from mutations of the genes of hormones (such as growth hormone), of a factor that regulates their synthesis or secretion (such as TPIT for corticotrophics), or of their receptors (GHRH or GnRH receptor genes). Multiple (or combined) pituitary hormone deficiencies result in the concomitant or sequential onset of several anterior pituitary hormone deficiencies. They are due to mutations of transcription factors involved in the early steps of pituitary development (RIEG, HesX1, LHX4, LHX3, Prop1, POU1F1/Pit-1), and are associated with various phenotypes. FOR BETTER MANAGEMENT: Long-term follow-up of these patients and functional studies of the mutations identified in specialized research centers will help to determine phenotype-genotype correlations, hence providing a valuable help to the management of these orphan diseases.