Familial<unk>  hypercalcemia (FHH]) is<unk>  by a mutation in the calcium-sensing receptor (CaSR) gene located on the chromosome 3. The chief cells of the parathyroid gland and the lining the kidney tubule express CaSR, a G protein coupled plasma membrane receptor which  has the ability to sense small changes in circulating calcium concentration. This information is sent to intracellular signaling pathways that modify PTH secretion or renal calcium handling. Inherited abnormalities of the CaSR gene located on chromosome 3p13.3-21 can<unk> either hypercalcemia or hypocalcemia. Inactivating mutation<unk>  hypercalcemia, whereas the activating mutation<unk>  hypocalcemia. Heterozygous loss-of-function mutations give rise to FHH, an asymptomatic hypercalcemia. The homozygous mutation manifests as neonatal severe hyperparathyroidism, a rare disorder characterized by extreme hypercalcemia and the bony changes of hyperparathyroidism. The disorder is known to be autosomal dominant hypocalcemia due to a gain-of-function mutations in the CaSR gene; this may be asymptomatic or may present with seizures. The three types of FHH are known to be<unk>  due to different genetic mutations. Type-1 FHH is<unk>  by a loss-of-function mutations of the CaSR, a G-protein coupled receptor that predominantly signals via G-protein subunit alpha-11 (Gα11) to regulate calcium homeostasis located on chromosome 3q13.3-q21. Type-2 FHH is<unk>  by heterozygous mutation in the GNA11 gene on chromosome 19p13. Type-3 FHH is<unk>  by heterozygous mutation in the AP2S1 gene on chromosome 19q13.
Familial hypocalciuric hypercalcemia causes
Familial hypocalciuric hypercalcemia other diagnostic studies
Pseudohypoparathyroidism other diagnostic studies
Hypoparathyroidism causes
Hypoparathyroidism other diagnostic studies
Hypoparathyroidism other imaging findings
Familial hypocalciuric hypercalcemia differential diagnosis
Familial hypocalciuric hypercalcemia pathophysiology