MAPPING OF THE CALCIUM-SENSING RECEPTOR GENE (CASR) TO HUMAN-CHROMOSOME 3Q13.3-21 BY FLUORESCENCE IN-SITU HYBRIDIZATION, AND LOCALIZATION TO RAT CHROMOSOME-11 AND MOUSE CHROMOSOME-16

The calcium-sensing receptor (CASR), a member of the G-protein coupled receptor family, is expressed in both parathyroid and kidney, and aid s these organs in sensing extracellular calcium levels. Inactivating m utations in the CASR gene have been described in familial hypocalciuri c hypercalcemia (FHH) and neonatal severe hyperparathyroidism (NSHPT). Activating mutations in the CASR gene have been described in autosoma l dominant hypoparathyroidism and familial hypocalcemia. The human CAS R gene was mapped to Chromosome (Chr) 3q13.3-21 by fluorescence in sit u hybridization (FISH). By somatic cell hybrid analysis, the gene was localized to human Chr 3 (hybridization to other chromosomes was not o bserved) and rat Chr 11. By interspecific backcross analysis, the Casr gene segregated with D16Mit4 on mouse Chr 16. These findings extend o ur knowledge of the synteny conservation of human Chr 3, rat Chr 11, a nd mouse Chr 16.