The prevalence of familial hypocalciuric hypercalcemia

Familial hypocalciuric hypercalcamia is said to be an extremely rare condit ion but is clinically important because it can be confused with primary hyp erparathyroidism. The biochemical features of the two conditions are simila r, but the former is benign while the latter can have serious clinical cons equences with patients occasionally proceeding to parathyroidectomy. It is therefore important to differentiate accurately between the two. With this in mind it would be useful to know the prevalence of familial hypocalciuric hypercalcemia when considering the differential diagnosis of primary hyper parathyroidism. However. as far as we are aware, no estimate of the prevale nce of this condition can be found in the literature. We describe how an es timate was made of the prevalence of familial hypocalciuric hypercalcemia i n the west of Scotland. We estimate the prevalence to be 1 in 78,000 at lea st.