CASE REPORT Idiopathic infantile hypercalcemia and renal involvement O. Sakallioglu Æ B. Hacihamdioglu Æ N. Balamtekin Æ S. Kalman Æ F. Gok Received: 10 September 2006 / Accepted: 25 February 2007 / Published online: 3 November 2007 Ó Springer Science+Business Media B.V. 2007 Abstract Idiopathic infantile hypercalcemia is rec- ognized as a rare cause of infantile hypercalcemia. Its renal consequences includenephrocalcinosis with distal tubular dysfunction, nephrolithiasis, and finally renalfailure.Herein we report the case ofa two- month-old infant presenting with idiopathic infantile hypercalcemia complicated with distal renaltubular acidosis(RTA) and nephrocalcinosis. Despite cor- rection ofacidosisand dehydration, the persistant hypercalcemia could only be ameliorated with calci- tonin treatment. Early diagnosisand appropriate treatment is life-saving in such cases. Keywords Idiopathic infantile hypercalcemia Distal tubular acidosis Nephrocalcinosis Calcitonin Introduction Idiopathic infantile hypercalcemia is a heterogeneous disorder that was originally described during a period of high-dose vitamin D fortification in England in the 1950s.Nonspecificsignsand symptomsuchas lethargy, hypotonia, poorfeeding, failure to thrive, dehydration, constipationandrespiratorydistress may emerge as early as the first few weeks of life [ 1]. The mostcommon cause of hypercalcemia in newborns is iatrogenic. Infantile hypercalcemia is divided into two subgroups, idiopathic infantile hyper calcemia(IIH) and Williamssyndrome. Williams syndrome is more severe and characterized by elfin face, cardiovascular defects, short stature and menta retardation [1]. Infantsusually present with thirst, dehydration and polyuria. The mechanism responsib for the hypercalcemia has not yetbeen fully under- stood. Some of these infants have elevated vitamin D metabolites, suggesting vitamin D intoxication and/o subtle renal dysregulation of vitamin D metabolism. Type 1 distal renaltubular acidosis (dRTA) is a clinical stateof systemicacidosisresulting from impaired urinary acidification, and is characterized b failure to thrive, polyuria, constipation, hyperchlore- mic metabolic acidosis, hypokalemia, hypercalciuria and nephrocalcinosis. Herein we report the case of a two-month-old IIH infant presenting with dRTA and nephrocalcinosis in whom hypercalcemia persisted despite correction of acidosis. Case A two-month-old boy was referred with malaise, poor sucking and failure to thrive. The parents were health B. Hacihamdioglu N. Balamtekin Department of Pediatrics, Gulhane Military Academy of Medicine, Ankara,Etlik,Turkey O. Sakallioglu (&) S.Kalman F.Gok Pediatric Nephrology Unit, Gulhane Military Academy of Medicine, Ankara,Etlik 06018, Turkey e-mail: onursakallioglu@yahoo.com 123 Int Urol Nephrol (2008) 40:535–537 DOI 10.1007/s11255-007-9199-5