Familial hypocalciuric hypercalcaemia

Familial hypocalciuric hypercalcaemia is an autosomal dominant condition which results in asymptomatic mild hypercalcaemia.

Bloods show mildly raised calcium and a normal or mildly raised PTH.

Familial hypocalciuric hypercalcaemia can be distinguished from primary hyperparathyroidism by fractional urinary calcium excreation:

• Patients with familial hypocalciuric hypercalcaemia: fractional urinary calcium excreation <0.01
• Patients with primary hyperparathyroidism: fractional urinary calcium excreation >0.02

It is important to distinguish the two as primary hyperparathyroidism requires treatment whilst familial hypocalciuric hypercalcaemia does not.

References:

Blackburn, M. and Diamond, T. Primary hyperparathyroidism and familial hyperparathyroid syndromes. Aust Fam Physician. 2007; 36(12): 1029-1033.

Taniegra, E. Hyperparathyroidism. Am Fam Physician. 2004; 69(2): 333-339.