Activating Calcium-Sensing Receptor Mutations: Prospects for Future Treatment with Calcilytics

Area of Science:

• Endocrinology
• Genetics
• Pharmacology

Background:

• Activating mutations in the calcium-sensing receptor (CaSR) lead to autosomal dominant hypocalcemia and Bartter syndrome type 5.
• These mutations disrupt calcium homeostasis by lowering the extracellular calcium set-point, resulting in reduced parathyroid hormone secretion and altered renal calcium handling.

Purpose of the Study:

• To evaluate calcilytics as a therapeutic strategy for conditions caused by activating CaSR mutations.
• To assess the efficacy of CaSR antagonists in correcting the molecular defect and improving clinical outcomes in vivo.

Main Methods:

• In vitro studies to assess CaSR antagonist activity on mutated CaSR proteins.
• In vivo studies in mouse models and human subjects to evaluate the effects of calcilytics on serum calcium levels.

Main Results:

• Calcilytics effectively attenuate the activity of activating CaSR mutants in vitro.
• Administration of calcilytics led to elevated serum calcium levels in both mouse models and human patients.

Conclusions:

• Calcilytics represent a promising therapeutic approach for rare diseases associated with activating CaSR mutations.
• These CaSR antagonists offer a potential solution for symptom relief and prevention of adverse outcomes in affected individuals.