A familial syndrome of hypocalcemia with hypercalciuria due to mutations in the calcium-sensing receptor

S H Pearce, C Williamson, O Kifor, M Bai, M G Coulthard, M Davies, N Lewis-Barned, D McCredie, H Powell, P Kendall-Taylor, E M Brown, R V Thakker

Research output: Contribution to journalArticlepeer-review

524 Citations (Scopus)

Abstract

BACKGROUND: The calcium-sensing receptor regulates the secretion of parathyroid hormone in response to changes in extracellular calcium concentrations, and mutations that result in a loss of function of the receptor are associated with familial hypocalciuric hypercalcemia. Mutations involving a gain of function have been associated with hypocalcemia in two kindreds. We examined the possibility that the latter type of mutation may result in a phenotype of familial hypocalcemia with hypercalciuria.

METHODS: We studied six kindreds given a diagnosis of autosomal dominant hypoparathyroidism on the basis of their hypocalcemia and normal serum parathyroid hormone concentrations, a combination that suggested a defect of the calcium-sensing receptor. The hypocalcemia was associated with hypercalciuria, and treatment with vitamin D resulted in increased hypercalciuria, nephrocalcinosis, and renal impairment. Mutations in the calcium-sensing-receptor gene were identified by DNA-sequence analysis and expressed in human embryonic kidney cells (HEK-293).

RESULTS: Five heterozygous missense mutations (Asn118Lys, Phe128Leu, Thr151Met, Glu191Lys, and Phe612Ser) were detected in the extracellular domain of the calcium-sensing-receptor gene and shown to cosegregate with the disease. Analysis of the functional expression of three of the mutant receptors in HEK-293 cells demonstrated shifts in the dose-response curves so that the extracellular calcium concentrations needed to produce half-maximal increases in total inositol phosphate in the cells were significantly (P=0.02 to P<0.001) lower than those required for the wild-type receptor.

CONCLUSIONS: Gain-of-function mutations in the calcium-sensing receptor are associated with a familial syndrome of hypocalcemia with hypercalciuria that needs to be distinguished from hypoparathyroidism.

Original languageEnglish
Pages (from-to)1115-1122
Number of pages8
JournalNew England Journal of Medicine
Volume335
Issue number15
DOIs
Publication statusPublished - 10 Oct 1996

Keywords

  • Adolescent
  • Adult
  • Aged
  • Amino Acid Sequence
  • Base Sequence
  • Calcium
  • Child
  • Child, Preschool
  • Diagnosis, Differential
  • Female
  • Humans
  • Hypocalcemia
  • Hypoparathyroidism
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Parathyroid Hormone
  • Pedigree
  • Phenotype
  • Point Mutation
  • Polymorphism, Single-Stranded Conformational
  • Receptors, Calcium-Sensing
  • Receptors, Cell Surface
  • Syndrome

Fingerprint

Dive into the research topics of 'A familial syndrome of hypocalcemia with hypercalciuria due to mutations in the calcium-sensing receptor'. Together they form a unique fingerprint.

Cite this