Aip, short for aryl hydrocarbon receptor-interacting protein, is a co-chaperone of heat-shock protein 90 and various nuclear receptors. It belongs to the family of tetratricopeptide repeat (TPR)-containing proteins and has three TPR domains mediating its interactions with partners. Germline mutations in Aip predispose to young-onset pituitary tumours, often GH-or prolactin-secreting adenomas, suggesting its importance in pituitary gland function [2].

Germline loss-of-function heterozygote mutations in Aip lead to a predisposition to growth hormone-or prolactin-secreting pituitary tumours, typically presenting in childhood, indicating its role as a tumour suppressor in the context of pituitary tumourigenesis [3]. AIP mutations are rare in sporadic acromegaly but are more frequent among certain pituitary adenoma patient populations, such as those with pituitary gigantism (29% of this group have AIP gene mutations), familial isolated pituitary adenoma (FIPA) kindreds, and patients with macroadenomas diagnosed ≤30 years old [1].

In conclusion, Aip functions as a co-chaperone and is crucial in pituitary gland-related biological processes. The study of Aip, especially through understanding the effects of its loss-of-function mutations, has significant implications for the diagnosis and treatment of pituitary-related diseases like pituitary gigantism, acromegaly, and familial isolated pituitary adenomas.