Familial Isolated Pituitary Adenoma: Evidence for Genetic Heterogeneity

The identification of mutations in the Aryl hydrocarbon receptor interacting protein (AIP) gene in a subset of familial isolated pituitary adenoma (FIPA) cases has recently expanded our understanding of the pathophysiology of inherited pituitary adenoma disorders. However, a genetic cause of has not yet been determined in the majority (85%) of FIPA families and half of the families with isolated familial somatotropinoma. Several studies and reviews have assessed the genetic and clinical features of AIP-mutated FIPA patients, which range from a complete lack of symptoms in adult/elderly individuals to large, aggressive early-onset pituitary tumors. In this study, we aimed to briefly revise the data available for the 11q13 locus and other additional loci that have been implicated in genetic susceptibility to FIPA: 2p16-12; 3q28; 4q32.3-4q33; chr 5, 8q12.1, chr 14, 19q13.4 and 21q22.1. These candidate regions may contain unidentified gene(s) that can be potentially disrupted in AIP-negative FIPA families. A better knowledge of these susceptibility loci may disclose modifier genes that are likely to play exacerbating or protective roles in the phenotypic diversity of AIP-mutated families.