ESPE Abstracts

Background: Autosomal-dominant hypocalcemia hypercalciuria (ADHH) is rare a genetic disorder characterized by hypocalcemia, hypercalciuria, low or inappropriately normal levels of parathyroid hormone caused by heterozygous activating mutation of calcium sensing receptor. It may be familial or sporadic with variable genotype and phenotype correlation.

Objective: We are reporting a de-novo heterozygous variant of the CaSR gene (c.374T>C p.(leu125Pro)) in a Pakistani infant who presented with persistent hypercalciuric hypocalcemia, hypomagnesemia, and a low PTH level.

Case Summary: We are reporting a 4-month-old girl who was referred to our endocrine clinic with concern for persistent hypocalcemia leading to multifocal seizures. At the presentation, she was on anti-epileptics and calcium supplements for uncontrolled fits and had bilateral cataracts. Her bone profile revealed hypocalcemia, hyperphosphatemia, hypomagnesemia, hypercalciuria, a toxic 25-OH vitamin D level, and a low parathyroid hormone, with an ultrasound kidney showing bilateral nephrocalcinosis. Her whole exome sequencing reported that she is carrying a heterozygous activating mutation in CASR c.374T>C p. (leu125Pro), with both parents being normal, confirming the diagnosis of autosomal dominant hypercalciuric hypocalcemia. After initial stabilization, she was discharged on calcium carbonate, alfacalcidol, magnesium sulphate, and thiazide diuretics.

Conclusion: Activating CaSR mutations are rare conditions that lead to hypocalcemia and hypercalciuria at the same time. Any child presenting with hypoparathyroidism with a raised urinary calcium-creatinine ratio should alert their physician to consider this rare entity.