Endocrine Abstracts

Cumulative genetic abnormalities within an oncogenic pathway may contribute to earlier onset or increased aggressiveness of cancers. An example in human and murine cancer is the dysregulation of Wnt signalling by inactivation of the adenomatous polyposis coli (APC) gene that results in accumulation of nuclear β-catenin and earlier onset of renal cell carcinoma, which can be accelerated by p53-deficiency. We therefore investigated the effects of such cumulative genetic abn...

Mutations of the transcription factor GATA3, which is important for maintaining human breast luminal epithelial cell differentiation and quiescence, have been reported in 17 oestrogen receptor (ER) positive breast cancers, although the functional effects of these mutations have not been studied. We therefore investigated 56 ER-positive breast cancers for GATA3 mutations. The tumours were macrodissected, and immunohistochemistry for GATA3 revealed a strong correlation between E...

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...

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...

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...

Multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant disorder characterised by the occurrence of parathyroid, pancreatic islet and anterior pituitary tumours, is due to mutations of a tumour suppressor gene, MEN1. MEN1 mutations have also been reported to cause familial isolated primary hyperparathyroidism (FIHP). Moreover, 15 identical MEN1 mutations have been reported to cause MEN1 or FIHP in unrelated families; thereby implicating a r...

Renal calcification (nephrocalcinosis), which has a multi-factorial etiology involving environmental and genetic determinants, affects ~8% of adults by 70 years. Nephrocalcinosis may occur as a familial disorder in ~65% of patients, and in 70% of patients, nephrocalcinosis may be associated with endocrine and metabolic disorders that include primary hyperparathyroidism, renal tubular acidosis, hypercalciuria, cystinuria, and hyperoxaluria. Investigations of families with hered...