Patients with FIHP more frequently present with severe hypercalcemia when compared with MEN1 patients or sporadic pHPT patients, and the provisional diagnosis of FIHP may, in ∼20% of patients, be reclassified as HPT‐JT, MEN1, or familial hypocalciuric hypercalcemia (FHH) following development of syndromic manifestations (Simonds et al., 2002; Pontikides et al., 2014). This evidence concerns the gene MEN1 and familial isolated hyperparathyroidism.