Neonates with JMC have severe, but largely asymptomatic hypercalcaemia, hypophosphatemia, hyperphosphaturia, elevated circulating levels of 1,25-dihydroxyvitamin D3, elevated serum alkaline phosphatase, and low or undetectable levels of PTH and PTH-related peptide (PTHrP) [44]. This evidence concerns the gene PTH and Hypercalcemia.