Normal total and ionized Ca and high PTH. 25(OH)D ≥ 20 ng/ ml (patients with low vitamin D were treated, and PTH had to be elevated after retested at 3 mo). Excluded cases with renal insufficiency, calcium malabsorption, hypercalciuria, medications (PPI, thiazides, lithium). The gene discussed is PTH; the disease is Hypercalciuria.