Autosomal Dominant Hypocalcemia With Atypical Urine Findings Accompanied by Novel CaSR Gene Mutation and VitD Deficiency

© The Author(s) 2020. Published by Oxford University Press on behalf of the Endocrine Society..

INTRODUCTION: Autosomal dominant hypocalcemia (ADH) is caused by gain-of-function mutations of the calcium sensing receptor (CaSR). It is characterized by hypercalciuria in spite of hypocalcemia. Vitamin D deficiency increases calcium reabsorption in the distal tubules of the kidneys, resulting in hypocalciuria.

MATERIALS AND METHODS: A 38-year-old female proband had hypocalcemia, hypocalciuria, and vitamin D deficiency. Her father and brother also had hypocalcemia, but her mother was normocalcemic. We analyzed the CaSR gene abnormality in this family. Polymerase chain reaction (PCR) and sequence analysis were performed to explore the CaSR gene mutation. Mutagenesis, transfection, and functional analysis were performed on the discovered genetic abnormalities.

RESULT: PCR and sequence analysis revealed that the proband, her father, and brother had a novel heterozygous mutation of the CaSR genes that causes threonine to asparagine substitution at codon 186 (T186N). Using HEK293 cells transfected with wild-type or T186N CaSR complementary DNA, we assessed the intracellular Ca2+ concentration in response to changes in the extracellular Ca2+ concentration. The cells transfected mutant CaSR gene had higher activity than that of wild-type. Therefore, we determined our patient had ADH with a novel mutation of the CaSR gene and hypocalciuria resulting from a vitamin D deficiency. We administered vitamin D to the proband, which caused elevation of her urinary calcium level, a typical finding of ADH.

CONCLUSION: Vitamin D deficiency was suggested to potentially mask hypercalciuria in ADH. Hypocalcemia with vitamin D deficiency should be diagnosed with care.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:5

Enthalten in:

Journal of the Endocrine Society - 5(2021), 3 vom: 01. März, Seite bvaa190

Sprache:

Englisch

Beteiligte Personen:

Tsuji, Tomoya [VerfasserIn]
Hiroyuki, Ariyasu [VerfasserIn]
Uraki, Shinsuke [VerfasserIn]
Doi, Asako [VerfasserIn]
Morita, Shuhei [VerfasserIn]
Iwakura, Hiroshi [VerfasserIn]
Nishi, Masahiro [VerfasserIn]
Furuta, Hiroto [VerfasserIn]
Akamizu, Takashi [VerfasserIn]

Links:

Volltext

Themen:

Autosomal dominant hypocalcemia
CaSR
Journal Article
Vitamin D deficiency

Anmerkungen:

Date Revised 20.04.2022

published: Electronic-eCollection

Citation Status PubMed-not-MEDLINE

doi:

10.1210/jendso/bvaa190

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM320678784