Screening for AIP mutations in patients <30 years of age with sporadic pituitary macroadenoma could improve clinical management of this population, according to results of a study published in the European Journal of Endocrinology.

Mutations in the AIP gene, which encodes the aryl hydrocarbon receptor interacting protein, are frequent in patients with familial isolated pituitary adenomas (FIPA) but have also been reported in patients with other pituitary adenoma subtypes. Tumors arising from AIP mutations are large (macroadenomas) and occur at a young age.

To evaluate the use of focused genetic screening, Tichomirowa et al. studied 163 patients with sporadic pituitary macroadenoma (≥10 mm maximal diameter on MRI) diagnosed when patients were aged <30 years. Other genetic causes or FIPA had been excluded.

Germline AIP mutations were found in 11.7% of patients, and DNA sequence changes of uncertain significance or polymorphisms in the AIP gene in a further 5.5% of patients. Pathogenic AIP mutations were identified in 20.5% of individuals aged <18 years.

Overall, 13.3% of patients with sporadic somatotropinoma, 11.5% of patients with prolactinoma and 6.3% of patients with nonfunctioning pituitary adenoma had AIP mutations, whereas no mutations were found in individuals with Cushing disease or thyrotropinoma. Familial screening revealed mutations in the relatives of seven patients with AIP mutations, and a microadenoma was diagnosed in two of these relatives.