A 14-year-old Caucasian girl with a history of primary hypoparathyroidism and unstable calcium and phosphorus levels and on ongoing treatment was admitted to the Department of Pediatric Nephrology because of the onset of nephrocalcinosis and difficulties achieving normocalcemia. Coexistence of hypoparathyroidism, oral candidiasis, dental enamel hypoplasia, and subclinical Hashimoto's disease was strongly suggestive for autoimmune polyglandular syndrome (APS) type I. One of the clinical implications of this diagnosis is the high probability of future occurrence of adrenal insufficiency and hence the importance of maintaining a high level of suspicion in case of the onset of symptoms like weakness, fainting, hypotonia, or hyperkaliemia. Addison's disease would, in fact, be quite challenging for the future management of this patient.This clinical quiz highlighted the importance of careful evaluation of all multiorgan symptoms occurring in a patient to prevent further complications.