Circulating PTHrP measurement in the assessment of severe hypercalcaemia in an infant

Parathyroid hormone-related protein (PTHrP) can simulate most of the actions of parathyroid hormone (PTH) including increases in bone resorption and distal tubular calcium reabsorption and inhibition of proximal tubular phosphate transport.1 The low serum phosphate in parallel with low circulating PTH is consistent with PTHrP involvement in this case. Whether it can be causative for a serum calcium of 6.24 mmol/L however is a moot point. While...