Contents

Search

familial hypocalciuric hypercalcemia

Epidemiology: - rare Pathology: - reduced activity of Ca+2 sensing receptor (CASR) - FHH is characterized by altered Ca+2 homeostasis Genetics: - associated with a defect in Ca+2 sensing receptor (CASR) in parathyroid cells Clinical manifestations: - generally asymptomatic Laboratory: 1) serum calcium: mild to moderate hypercalcemia 2) urine calcium: - low urinary Ca+2 excretion in distinction to hyperparathyroidism - 24 hour urine calcium < 200 mg/24 hours - urine calcium/creatinine ratio < 0.01 [1] 3) serum creatinine & urine creatinine for calculation of calcium to creatinine clearance ratio [1] - calcium [urine] (mg/dL) x creatinine [serum] (mg/dL) ---------------------------------------------------- calcium [serum] (mg/dL) x creatinine [urine] (mg/dL) - a ratio of < 0.01 suggests familial hypocalciuric hypercalcemia 4) serum PTH is variable, may be high or inappropriately normal 5) CASR gene mutation if diagnosis is clinically ambiguous [1] Differential diagnosis: - hyperparathyroidism - idiopathic hypercalciuria - absorptive hypercalciuria Management: - benign condition - does not resolve with parathyroidectomy - no treatment indicated [1,4]

Specific

familial hypocalciuric hypercalcemia type I familial hypocalciuric hypercalcemia type II familial hypocalciuric hypercalcemia type III

General

genetic disease of the endocrine system hypercalcemia

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2015, 2018. - Medical Knowledge Self Assessment Program (MKSAP) 20 American College of Physicians, Philadelphia 2025
  2. Christensen SE, Nissen PH, Vestergaard P, Mosekilde L. Familial hypocalciuric hypercalcaemia: a review. Curr Opin Endocrinol Diabetes Obes. 2011 Dec;18(6):359-70 PMID: 21986511
  3. Shinall MC Jr, Dahir KM, Broome JT. Differentiating familial hypocalciuric hypercalcemia from primary hyperparathyroidism. Endocr Pract. 2013 Jul-Aug;19(4):697-702. Review. PMID: 23425644
  4. Hoppner J, Sinningen K, Raimann A, et al. Disorders of the calcium sensing signaling pathway: from familial hypocalciuric hypercalcemia (FHH) to life threatening conditions in infancy. J Clin Med. 2022;11:2595. PMID: 35566721