Pituitary Stalk Interruption Syndrome and Isolated Pituitary Hypoplasia May Be Caused by Mutations in Holoprosencephaly-Related Genes

Context: Holoprosencephaly (HPE) is a developmental defect characterized by wide phenotypic variability, ranging from minor midline malformations (eg, single central incisor) to severe deformities. In 10–15% of HPE patients, mutations in specific genes have been identified (eg, SHH, TGIF, SIX3). Pituitary stalk interruption syndrome (PSIS) constitutes a distinct abnormality of unknown pathogenesis, whereas isolated pituitary hypoplasia (IPH) has been linked to various developmental genes. Objective: Three of our patients with PSIS had a single central incisor, a malformation encountered in some HPE cases. Based on this observation, we initiated a search for mutations in HPE-associated genes in 30 patients with PSIS or IPH. Design and Participants: The entire coding region of the TGIF, SHH, and SIX3 genes was sequenced in patients with combined pituitary hormone deficiency associated with either PSIS or IPH and in healthy controls. Results: Two novel mutations in the HPE-related genes were detected (ie, c....