Recent clinical practice guidelines recommend that routine screening of MEN1 mutation carriers should start at the age of 5 years. The occurrence of clinically relevant MEN1 organ manifestations in children (≤18 years) was evaluated. Two prospective collected databases of MEN1 patients (n = 166) who underwent annual screening were retrospectively analyzed for organ manifestations in MEN1 patients ≤18 years. The follow-up was based on the most recent screening examination until December 2015. Twenty [11 females, 9 males, (12%)] of 166 MEN1 patients were diagnosed with at least one organ manifestation at age ≤18 years. The most frequent manifestation was mild asymptomatic pHPT (n = 9, 45%, age range 8–18 years). Eight (40%) young patients had pNENs (three non-functioning pNENs, five insulinomas, age range 9–18 years). All five insulinomas were diagnosed based on hypoglycemic symptoms. The other organ manifestations were asymptomatic pituitary adenomas in six patients (30%, age range 15–18 years) and a bronchial carcinoid in one 15-year-old patient. Only six (30%) patients ≤18 years had clinically relevant organ manifestations. Symptomatic or severe manifestations in MEN1 patients rarely occur below the age of 16 years. With regard to psychological burden and cost-effectiveness, routine screening of asymptomatic MEN1 patients should be postponed at least until the age of 16 years.
