Familial disorders of the parathyroid gland

The molecular mechanisms for familial parathyroid diseases include a wide spectrum of genes and are better understood than those of sporadic parathyroid lesions. Familial parathyroid disease is present in patients with multiple endocrine neoplasia type 1 (MEN-1), which is associated with MEN-1 mutations, while multiple endocrine neoplasia type 2A (MEN-2A) is associated with RET mutations. Sporadic parathyroid tumours are identified with mutations of MEN-1 but not of RET. Mutations in the calcium sensing receptor gene are involved in familial hyper- and hypo-parathyroidism, but are not identified in sporadic parathyroid tumours. The HRPT2 gene, which is mutated in hyperparathyroidism-jaw tumour syndrome and familial isolated hyperparathyroidism, is also frequently mutated in sporadic parathyroid carcinomas. Recent studies have suggested that parafibromin, a protein encoded by HRPT2, may be used in the diagnosis of parathyroid tumours. The discovery of additional molecular alterations in parathyroid tumours should provide new information about the development of these tumours and may provide new tools for the diagnosis and treatment of parathyroid tumours.