The international guidelines on evaluation and management of PHPT suggest genetic testing performed on patients with young-onset PHPT (age ≤30 years), multiglandular disease, family history of hypercalcemia or syndromic diseases (MEN1, MEN2, HPT-JT), or atypical parathyroid adenoma or PC to uncover and identify heritable origins of the disease [13]. The gene discussed is MRS2; the disease is Hypercalcemia.