Biochemical assessment of the index case confirmed the diagnosis of hyperparathyroidism with severe hypercalcemia (serum Caalb adj = 14.9 mg/dL, nr = 8.4–10.2 mg/dL; PTH = 703 pg/mL, nr = 15–65 pg/mL). The gene discussed is PTH; the disease is hypercalcemia disease.