Endocrine Abstracts

Loss- and gain-of-function mutations of the calcium-sensing receptor (CaSR) cause familial hypocalciuric hypercalcaemia (FHH) and autosomal dominant hypocalcaemia (ADH), respectively. The CaSR is a homodimeric receptor that has a 612 amino acid extracellular domain (ECD), which binds extracellular calcium (Ca2+e) and mediates dimer interactions upon ligand binding. The ECD consists of lobes 1 and 2, and a cysteine-rich domain (CRD). To elucidate the struc...

Loss- and gain-of-function mutations of the calcium-sensing receptor (CaSR) cause familial hypocalciuric hypercalcaemia (FHH) and autosomal dominant hypocalcaemia (ADH), respectively. The CaSR is a homodimeric receptor that has a 612 amino acid extracellular domain (ECD), which binds extracellular calcium (Ca2+e) and mediates dimer interactions upon ligand binding. The ECD consists of lobes 1 and 2, and a cysteine-rich domain (CRD). To elucidate the struc...

Familial hypocalciuric hypercalcaemia (FHH) is an inherited disorder of calcium homeostasis, which is caused by germline loss-of-function mutations of the calcium-sensing receptor (CaSR) in ˜70% of cases. We report a 22 year old woman who was referred with asymptomatic hypercalcaemia. Biochemical investigations revealed hypercalcaemia on 3 of 4 occasions with adjusted serum calcium ranging from 2.59–2.80 mmol/l (normal range 2.20–2.60 mmol/l). Parathyroid hormon...

Case History: X-linked hypophosphataemia (XLH) manifests as rickets in infancy or childhood, and is caused by mutations of the phosphate-regulating neutral endopeptidase (PHEX) gene, which leads to excess production of the fibroblast growth factor-23 (FGF-23) hormone. We present a case illustrating that mutation of PHEX can also cause hypophosphataemia presenting in adulthood. The proband is a 56-year-old male, who was referred with persistent hypophosphataem...

G-protein subunit α-11 (Gα11), which is encoded by GNA11, plays a major role in calcium homeostasis by regulating parathyroid hormone (PTH) secretion, and germline loss-of-function mutations cause familial hypocalciuric hypercalcaemia type 2 (FHH2). Since Gα11 is ubiquitously expressed, we investigated whether FHH2 is associated with additional non-calcitropic phenotypes by analysing mice harbouring a homozygous germline deletion o...