Activating parathyroid hormone (PTH)/PTH‐related Peptide (PTHrP) receptor (PTH1R) mutations causes Jansen's metaphyseal chondrodysplasia (JMC), a rare disease characterized by growth plate abnormalities, short stature, and PTH‐independent hypercalcemia. The gene discussed is PTH; the disease is metaphyseal chondrodysplasia, Jansen type.