The human calcium-sensing receptor (<i>CASR</i>) is the key controller of extracellular Ca<sub>o</sub><sup>2+</sup> homeostasis, and different mutations in the <i>CASR</i> gene have been linked to different calcium diseases, such as familial hypocalciuric hypercalcemia, severe hyperparathyroidism, autosomal-dominant hypocalcemia (ADH), and Bartter's syndrome type V. In this study, two generations of a family with biochemically and clinically confirmed ADH who suffered severe muscle pain, arthralgia, tetany, abdominal pain, and fatigue were evaluated for mutations in the <i>CASR</i> gene.