Mild infantile hypercalcemia: Diagnostic tests and outcomes

Objective: To assess outcome in a cohort of patients with infantile hypercalcemia followed over 3 years. Study design: Patients (n = 32) presenting to the calcium clinic between July 2002 and September 2008 were studied. In addition to tests of calcium phosphate metabolism, serum insulin-like growth factor-1, calcitonin, urine citrate, and calcium-sensing receptor gene analysis were obtained. Results: Mean age at presentation was 6.0 ± 6.3 months. Mean calcium level was 11.4 ± 0.7 mg/dL (2.84 ± 0.17 mmol/L). A recognized cause was found in 14% and a probable cause in 14 % of the cohort. Those with nephrocalcinosis (n = 11) had significantly lower mean weight SDS and higher mean calcium levels. The biochemical profile of those in whom no cause could be determined included nonsuppressed parathyroid hormone with either normal or increased 1,25(OH)₂D. Hypercalcemia resolved in 20 patients. However, in approximately a third, there was persistence in hypercalcemia, hypercalciuria, or nephrocalcinosis. Conclusions: The addition of 1,25(OH)₂D and calcium-sensing receptor mutation analysis to a panel of investigations may improve diagnostic yield. Clinical outcome is overall good, however, one-third need ongoing follow-up.