The NSHPT associated with biallelic Gly768Val mutations of the CASR in two siblings with severe hypercalcemia and hyperparathyroidism and their clinically and biochemically normal heterozygous parents was transmitted as an autosomal recessive disorder in this family.
In a case of neonatal severe hyperparathyroidism characterized by moderately severe hypercalcemia and very high PTH levels, coupled with evidence of hyperparathyroidism and effects on brain development not previously demonstrated, we detected point mutations on separate alleles of the CaR, resulting in premature stop codon substitutions at G94 and R648.
Parathyroidectomy may also be appropriate in disorders with generalized resistance to Ca2+o owing to inactivating CaR mutations in the following special circumstances: in selected families with FHH in which there is unusually severe hypercalcemia, frankly elevated PTH levels, or atypical features such as hypercalciuria; in cases of NSHPT with severe hypercalcemia and hyperparathyroidism; and in the occasional mild case of homozygous FHH owing to CaR mutations that confer mild-to-moderate resistance to Ca2+o that escapes clinical detection in the neonatal period.
Parathyroid surgery in familial HPT syndromes in the setting of underlying mutations in the calcium receptor (CASR) gene involves radical subtotal parathyroidectomy.
In familial hypocalciuric hypercalcemia (FHH), heterozygous inactivating mutations in the CaSR gene produce mild, generally asymptomatic hypercalcemia, whereas in neonatal severe hyperparathyroidism (NSHPT), homozygous inactivating mutations cause severe hypercalcemia and hyperparathyroidism.
Therefore, CaSR is an important target for treating digestive diseases, and the calcimimetics (CaSR agonist) have been confirmed as practical, feasible and effective clinical therapies for hyperparathyroidism.
Issue 4: parathyroid surgery in familial HPT syndromes in the setting of underlying mutations in the calcium receptor (CASR) gene involves subtotal parathyroidectomy (no grade of recommendation).
We compared the expression of the calcium-sensing receptor (CaR) at the gene message and the protein level in parathyroid tissue obtained from patients with I degree non-uremic or II degree uremic hyperparathyroidism with that in normal parathyroid tissue, using in situ hybridization and immunohistochemistry techniques.
Here, we investigate a unique variant of familial hypercalcemia, unrelated to multiple endocrine neoplasia and hyperparathyroidism-jaw tumor syndromes, with hypercalcemia due to a point mutation in the intracellular part of the calcium receptor (CaR) gene.
In addition, it examines the use or potential use of CaSR agonists or antagonists (calcimimetics and calcilytics) and other drugs mediated through the CaSR, in the management of disorders as diverse as hyperparathyroidism, osteoporosis and gastrointestinal disease.
The CASR is a potential therapeutic target to treatment of diseases including hyperparathyroidism and osteoporosis, since its interaction with pharmacological compounds results in modulation of PTH secretion.
Cinacalcet therapy in an infant with an R185Qcalcium-sensing receptor mutation causing hyperparathyroidism: a case report and review of the literature.
A total of 21 patients were evaluated, seven of them with idiopathic hypoparathyroidism (suspected ADHH) and 14 with hyperparathyroidism (suspected FHH).
These include chromosomal deletions of the MEN1 locus on 11q in sporadic and MEN1 associated primary HPT, of RB1 on 13q in carcinomas, and of the FHH gene located on 3q in sporadic primary and secondary HPT.
The human calcium-sensing receptor (<i>CASR</i>) is the key controller of extracellular Ca<sub>o</sub><sup>2+</sup> homeostasis, and different mutations in the <i>CASR</i> gene have been linked to different calcium diseases, such as familial hypocalciuric hypercalcemia, severe hyperparathyroidism, autosomal-dominant hypocalcemia (ADH), and Bartter's syndrome type V. In this study, two generations of a family with biochemically and clinically confirmed ADH who suffered severe muscle pain, arthralgia, tetany, abdominal pain, and fatigue were evaluated for mutations in the <i>CASR</i> gene.
The calcium-sensing receptor (CaSR) plays an important role in sensing extracellular calcium ions and regulating parathyroid hormone secretion by parathyroid gland cells, and the receptor is a suitable target for the treatment of hyperparathyroidism.
Finally, we will comment on the development of drugs that modulate CaR function by either activating (calcimimetic drugs) or antagonizing it (calcilytic drugs), and on their potential therapeutic implications, such as medical control of specific cases of primary and uremic hyperparathyroidism with calcimimetic drugs and a potential treatment for osteoporosis with a calcilytic drug.
Mutations in the hyperparathyroidism type 2 (HRPT2/CDC73) gene and alterations in the parafibromin protein have been established in the majority of parathyroid carcinomas and in subsets of parathyroid adenomas.
The findings support variable calcium insensitivity of [Ca2+]i and PTH release in hyperparathyroidism of MEN 1, apparently coupled to heterogeneously reduced CAS expression.