The A, B, C, D of hypercalcaemia in Down syndrome.

Hypercalcaemia in infants with Down syndrome is an uncommon condition with only five previous case reports. The patients often present in the toddler years with the classical triad of Down syndrome, biochemical hypercalcaemia, and nephrocalcinosis. We present the sixth case and second male with this condition and further review the clinical details of this under-recognised condition and stratify the diagnostic criteria. The management mandates a reduction in calcium intake as a first step. The natural history of the various aspects of this condition is also considered.