Endocrine Abstracts

The calcium-sensing receptor (CaSR) plays a central role in regulating parathyroid hormone (PTH) secretion in response to changes in extracellular calcium. The CaSR is a G-protein-coupled receptor and ligand binding results in stimulation of phospholipase C (PLC) activity, causing accumulation of inositol 1,4,5-triphosphate (IP3) and the rapid release of calcium ions from intracellular stores. Given the pivotal role of the CaSR in calcium homeostasis, we decided to ...

Ligand binding by the calcium-sensing receptor (CaSR), which belongs to family C of the G-protein coupled receptor super-family, activates the phospholipase C-inositol triphosphate pathway and leads to an increase in intracellular calcium. CaSR inactivating mutations result in the hypercalcaemic disorders of familial benign hypocalciuric hypercalcaemia (FBHH) and neonatal severe primary hyperparathyroidism (NSHPT), whilst activating mutations result in the hypocalcaemic disord...

Mutations leading to haploinsufficiency of the dual zinc finger transcription factor GATA3 result in the hypoparathyroidism-deafness-renal dysplasia (HDR) syndrome which is an autosomal dominant disorder. We investigated 21 HDR probands and 14 patients with isolated hypoparathyroidism for GATA3 abnormalities. Venous blood was obtained after informed consent, as approved by the local ethical committee, and leukocyte DNA extracted. GATA3 specific primers were used for PCR amplif...

The calcium-sensing receptor (CaSR) belongs to family C of G-protein coupled receptors (GPCRs) that bind glutamate, GABA, taste molecules and pheromones. Loss-of-function mutations of the CASR gene located on chromosome 3q21–24, cause familial benign hypocalciuric hypercalcaemia type 1 (FBHH1). The genes causing FBHH2 and FBHH3, whose chromosomal locations are on 19p and 19q13.3, respectively, remain unknown. FBHH3, sometimes called the Oklahoma variant (FBHHO...

Loss-of-function mutations of the calcium-sensing receptor (CaSR), a G-protein-coupled receptor (GPCR), result in familial hypocalciuric hypercalcaemia (FHH), a disorder of extracellular calcium homeostasis affecting the parathyroids and kidneys. However, around 35% of FHH patients do not have CaSR mutations. A form of FHH, designated FHH2, has been mapped to chromosome 19p. The GNA11 gene, encoding G-protein α11 (Gα11), a component of the CaSR sign...

The calcium-sensing receptor (CaSR) is a G protein-coupled receptor with an extracellular bilobed venus flytrap domain (VFTD) predicted to contain five calcium-binding sites. The major site for calcium-binding is comprised of amino acid residues that line the cleft between the two lobes of the VFTD. We investigated the structure-function relationships of VFTD CaSR mutations identified in patients with familial hypocalciuric hypercalcaemia (FHH), neonatal severe primary hyperpa...

The calcium sensing receptor (CaSR) is a G protein coupled receptor that is expressed in the parathyroids and kidneys, where it plays a pivotal role in the regulation of extracellular calcium homeostasis. Patients with activating CaSR mutations have autosomal dominant hypocalcaemia with hypercalciuria (ADHH), which is associated with polydipsia, polyuria, nephrocalcinosis and renal impairment. The Nuf mouse, which has an activating CaSR mutation (Leu723Gln) has been reported t...

Activating mutations of the calcium sensing receptor (CaSR) result in autosomal dominant hypocalcaemia with hypercalciuria (ADHH), in which patients may also suffer from polyuria, polydipsia, nephrocalcinosis, renal impairment, and ectopic calcification. A mouse model, Nuf, with an activating Leu723Gln CaSR mutation has been reported to develop the features of ADHH as well as cataracts that consist of dot nuclear opacities, which have not been described in ADHH patients...

The G-protein coupled calcium-sensing-receptor (CaSR) regulates calcium homeostasis and inactivating mutations result in familial hypocalciuric hypercalcaemia (FHH), whilst activating mutations result in autosomal dominant hypocalcaemia with hypercalciuria (ADHH). Allosteric CaSR modulators consist of: calcimimetics, which activate the CaSR e.g. Cinacalcet, that is used to treat the hypercalcaemia of chronic renal failure and metastatic parathyroid carcinoma; and calcilytics e...

(This poster is based on OC24)...