A 15-year-old boy comes to the office for health check-up. The patient is incidentally found to have mild hypercalcemia on laboratory testing. Further questioning reveals that several of his family members also have mild hypercalcemia. Subsequent laboratory studies show a borderline high parathyroid hormone concentration, very low urinary calcium level, and normal 25-hydroxyvitamin D level. A mutation in which of the following receptors is most likely responsible for this patient's laboratory abnormalities?

Question

A 15-year-old boy comes to the office for health check-up. The patient is incidentally found to have mild hypercalcemia on laboratory testing.  Further questioning reveals that several of his family members also have mild hypercalcemia.  Subsequent laboratory studies show a borderline high parathyroid hormone concentration, very low urinary calcium level, and normal 25-hydroxyvitamin D level.  A mutation in which of the following receptors is most likely responsible for this patient's laboratory abnormalities?

Quizplus · Accepted Answer

Eductional Objective: Calcium-sensing receptors are G protein-coupled receptors that regulate the secretion of parathyroid hormone in response to changes in circulating calcium levels.  Familial hypocalciuric hypercalcemia is a benign autosomal dominant disorder caused by defective calcium-sensing receptors in the parathyroid gland and kidneys.

A 15-Year-Old Boy Comes to the Office for Health Check-Up