title: Hyperparathyroid genes: sequences reveal answers and questions.
abstract: OBJECTIVE
  To review hyperparathyroid syndromes and genes.
  
  
  METHODS
  Pertinent original studies from the literature are discussed.
  
  
  RESULTS
  Six main hyperparathyroid syndromes are recognized; 5 are from germline mutations in 4 genes-CASR, MEN1, RET, and HRPT2. Each hyperparathyroid syndrome was first described around 1965; the main gene for each syndrome was identified about 30 years later. Gene identification addressed clinical issues. (1) Testing for mutation carriers among affected probands or among unaffected relatives is more robust than prior methods, which were based on syndromal traits such as serum calcium. (2) Interpreting a gene test (RET) could guide an important intervention; other gene tests could yield useful information for patients and physicians. (3) Proving the roles of each gene (in particular, MEN1 somatic mutations) provided insights about contributions to many common tumors. (4) Clarifying molecular pathways and drugs led, for example, to the CASR-aided development of calcimimetic and calcilytic drugs. (5) Explaining novel features, such as the CASR gene encoding a membrane calcium-sensing receptor and its mutations resulting in nonsuppressed parathyroid hormone secretion uncoupled from proliferation, characterized familial hypocalciuric hypercalcemia. (6) Disclosing probands without an identifiable mutation promoted searches for other syndromal genes. Subsequently, rare multiple endocrine neoplasia type 1-like families were shown to have inactivating germline mutations, first of p27 and subsequently of p15, p18, or p21.
  
  
  CONCLUSIONS
  The next frontier in mutation detection is arriving, with possible sequencing of the whole exome or even the whole genome for 1 case or 1 tumor at an affordable cost.
authors: Metabolic Diseases Branch and Genetics and Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. MarxS@mail.nih.gov
authors: Stephen J
authors: SJ
authors: Marx
mesh_terms: D018095:Germ-Line Mutation / Q000235:genetics; D006801:Humans; D006961:Hyperparathyroidism / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics
chemical_list: C105373:MEN1 protein, human; D011518:Proto-Oncogene Proteins