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familial hypocalciuric hypercalcemia
Epidemiology:
- rare
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 inappropriately normal
Differential diagnosis:
- hyperparathyroidism
- idiopathic hypercalciuria
- absorptive hypercalciuria
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
- Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18.
American College of Physicians, Philadelphia 1998, 2015, 2018.
- 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
- 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