Figure 5. Familial hyperparathyroidism. Familial hyperparathyroidism (FHPT) can occur in the MENI Syndrome, in which menin is mutated; in the MENII Syndrome, in which ret is mutated; in FHH and NSHPT in which CaSR is mutated; and in the Hyperparathyroidism-Jaw Tumor (HPT-JT) Syndrome in which HRPT2 is mutated.Familial isolated hyperparathyroidism(FIH) refers to familial hyperparathyroidism in the absence of the specific features of the other documented syndromes and suggests that other genes relevant to parathyroid neoplasia await identification.