1,25-dihydroxyvitamin D; the enzyme 1-alpha-hydroxylase converts inactive vitamin D (25-hydroxyvitamin D) into active vitamin D (1,25-dihydroxyvitamin D) within the kidney to regulate calcium and phosphorus absorption.

A genetic form of hypoparathyroidism caused by gain-of-function variants in the calcium-sensing receptor gene.¹

An irregular heartbeat.

Abnormal accumulation of calcium deposits in the brain.^1,2

Calcium-sensing receptor gene which encodes the calcium-sensing receptor protein. Activating or gain-of-function variants within this gene are causitive of ADH1.^1,3

Calcium-sensing receptor. A G protein-coupled receptor which is highly expressed in the parathyroid glands and kidney to regulate circulating calcium concentrations by altering parathyroid hormone secretion and urinary calcium excretion, respectively.^1,2

CaSR negative allosteric modulators designed to increase PTH secretion and decrease renal calcium excretion.⁴

The clouding of a normally clear lens in the eye.

Gradual loss of kidney function (inability to filter waste, toxins, and excess fluid).

An involuntary twitching of facial muscles, specifically around the mouth, nose, or eye in response to tapping the facial nerve. A positive Chvostek's sign represents hypocalcemia.⁵

Estimated glomerular filtration rate; a measurement of kidney function.

Excessive excretion of calcium in the urine.⁶

High phosphate levels in the blood.⁷

Low calcium levels in the blood.⁸

Sudden and involuntary closure or spasm of vocal cords that obstruct the airway, making it difficult to breathe.¹

Deposition of calcium in the kidney.⁹

Formation of hard mineral/calcium crystals in the kidneys, also known as kidney stones.¹⁰

Sensation of tingling, numbness or "pins and needles".^1,10

A heart rhythm disorder where the ventricles take too long to recharge between beats, which can increase the risk of dangerous abnormal heart rhythms.

Parathyroid hormone; secreted by the parathyroid gland in response to low calcium levels detected in the blood.¹¹

Abnormal electrical activity in the brain causing changes in consciousness and muscle control.^12,13

Involuntary muscle contractions that lead to painful muscle cramps and spasms.¹