Miñambres I, Corcoy R, Weetman AP, et al. - This study was undertaken to present two patients in whom the presence of autoimmune hypocalciuric hypercalcemia (AHH) was suspected and to evaluate the patients for the presence of calcium-sensing receptor (CaSR) antibodies. Researchers diagnosed CaSR antibodies and defined by immunoprecipitation assays, CaSR peptide ELISAs, and functional assays based on the calcium-stimulated accumulation of inositol-1-phosphate in a mammalian cell line expressing the CaSR. The results of this study demonstrate that AHH is to be suspected in patients with an acquired biochemical pattern of PTH-dependant hypocalciuric hypercalcemia, particularly in those with other concomitant autoimmune diseases. Diagnosis by means of detecting CaSR antibodies may assist to better define this probably under-reported condition.