Search

Introduction: Familial hypocalciuric hypercalcemia (FHH) is a group of autosomal dominant genetic diseases with persistent hypercalcemia and hypocalciuria. The calcium-sensitive receptor (CaSR) plays an important role in calcium and phosphorus metabolism., Patient Concerns: A 32-year-old man who had diabetes was admitted to our hospital due to poor glycemic control, and was found to have hypercalcemia, hypophosphatemia, and hyperparathyroidism. Single-Photon Emission Computed Tomography (SPECT) (99-mTcMIBI) examination result was negative. The result of 24-h urine calcium was 2.18 mmol/24 h, and the 24-h urinary calcium to creatinine ratio (UCCR) was 0.006. Family survey showed that all of the family members had hypercalcemia., Diagnosis: The CaSR gene mutation study revealed that the proband had a homozygous mutation for a T>C nucleotide substitution at c.1664 in exon 6, while both the mother and the father had heterozygous mutations at the same site of exon 6. The clinical diagnosis was considered to be FHH type1., Interventions: The patient was treated with conventional calcium-lowering therapy which was not effective. Cinacalcet was suggested but not used. The patient received salmon calcitonin nasal spray and furosemide tablets treatment for 1 month after discharge, and then stopped the medication., Outcomes: On follow up 4 months after being discharged, the serum calcium level was 3.18 mmol/L, and the PTH level was 275.4 ng/mL. He had felt fatigued, intermittent abdominal pain and lost 3.9 kg of weight., Conclusion: This case studied a family with FHH, and the CaSR gene c.1664T>c mutation was the possible pathogenic cause. If parathyroid location examination is unclear for hyperparathyroidism, the possibility of FHH should be considered. For FHH patients, conventional calcium reduction therapy was ineffective and parathyroid surgery cannot alleviate their hypercalcemia.

Purpose of Review: Variations in extracellular calcium level have a large impact on kidney function. Most of the effects seen are attributed to the calcium-sensing receptor (CaSR), a widely expressed G-protein-coupled cell surface protein with an important function in bone mineral homeostasis. The purpose of this review is to recapitulate the novel functional aspects of CaSR., Recent Findings: Results from mouse models demonstrate important functions for CaSR in various tissues. In the kidney, the main role of CaSR is the regulation of calcium reabsorption in the thick ascending limb, independently of its role on parathyroid hormone secretion. CaSR modulates claudin 14, the gatekeeper of paracellular ion transport in the thick ascending limb that is associated with urinary calcium excretion. One intracellular signaling pathway by which CaSR alters tight junction permeability is the calcineurin-NFAT1c-microRNA-claudin14 axis., Summary: The main function of CaSR in the kidney is the regulation of calcium excretion in the thick ascending limb, independently of parathyroid hormone. CaSR modulates paracellular cation transport by altering expression of the tight junction protein claudin 14. Still more work is needed to fully understand all functions of CaSR in the kidney. Alternative pathways of calcium 'sensing' in the kidney need to be investigated.

Altered mental status in a child is a potentially life-threatening condition with a broad differential including vascular, toxin-mediated, infectious, metabolic, and traumatic causes. Hypercalcemia is a rare cause of altered mental status in children. We report a case of a 13-month-old boy with familial hypocalciuric hypercalcemia who presented to our emergency department with altered mental status and hematemesis. Familial hypocalciuric hypercalcemia is a rare cause of hypercalcemia that usually presents with asymptomatic hypercalcemia. This case illustrates the presentation of severe hypercalcemia and reviews the initial management and evaluation of hypercalcemia in children.

The endocrine system is an embryological diverse system consisted of a variety of glands, such as pituitary, parathyroid, thyroid, adrenal, endocrine pancreas, and the diffuse neuroendocrine system. Endocrine tumor can be presented as a sporadic event, or as part of an inherited tumor syndrome. During the past century, inherited tumor syndromes have emerged as an important group of diseases. With the growing knowledge of each inherited tumor syndrome in the molecular genetic level, many changes in clinical management have occurred. This review focuses on the endocrine tumors involving the pituitary, parathyroid, thyroid, adrenal, and endocrine pancreas, in the setting of inherited tumor syndromes. We discuss the specific clinical, molecular genetic, and pathologic features of endocrine tumor in each gland and their associated inherited tumor syndromes. By understanding the pathogenesis of inherited endocrine tumor syndromes and recognizing the unique features of pathologic findings, pathologists bear the responsibility to provide the clinicians the guidelines in terms of screening and treatment of inherited tumor syndromes.