Objective: Pituitary adenomas (PA) are rare in young patients, and additional studies are needed to fully understand their pathogenesis in this population. We describe the clinical and genetic characteristics of apparently sporadic PA in a cohort of young patients. Design: Clinical and molecular analysis of 235 patients (age ≤ 30 years) with PA. Clinicians from several Spanish and Chilean hospitals provided data. Methods: Genetic screening was performed via next-generation sequencing and comparative genomic hybridization array. Clinical variables were compared among paediatric, adolescent (MEN1 alterations or a limited clinical expression of the syndrome. Despite the low penetrance observed, screening of AIP and MEN1 variants in young patients and relatives is of clinical value.