This frameshift mutation results in premature truncation of parafibromin, a tumor suppressor protein whose loss of function is strongly associated with PC, particularly in familial syndromes such as hyperparathyroidism-jaw tumor syndrome (HPT-JT) and familial isolated hyperparathyroidism (FIHP) [9,2]. The gene discussed is TCHP; the disease is Hyperparathyroidism-jaw tumor syndrome.