In this case, the patient's hypercalcemia was significant, with serum calcium reaching 5 mmol/L, necessitating aggressive management, including the use of bisphosphonates (zoledronic acid) and denosumab, an antibody against receptor activator of nuclear factor kappa-Β ligand (RANKL). The gene discussed is TNFSF11; the disease is hypercalcemia disease.