FAMILIAL IDIOPATHIC HYPERCALCIURIA

The frequency of hypercalciuria was determined in the families of nine hypercalciuric patients with idiopathic hypercalciuria who formed recurrent calcium oxalate renal stones. Idiopathic hypercalciuria occurred in 26 of 73 relatives, in three consecutive generations of two families and in two successive generations of four other families. Multiple siblings or children of the probands were affected in three families. Nineteen of 44 first-degree relatives (43 per cent) had idiopathic hypercalciuria, as compared to seven of 29 (29 per cent) other relatives; there was no relation to age or sex. Renal stones were formed by 19 of the 44 first-degree relatives but by none of the others; nine of the 19 were women. We conclude that there is a familial form of hypercalciuria, which appears to be transmitted as an autosomal dominant trait. Stone disease is frequent in first-degree relatives, and affects both sexes equally. (N Engl J Med 300:337–340, 1979) IDIOPATHIC hypercalciuria occurs in about 40 per cent of patients who form calcium renal stones, and is an important, remediable cause of stone disease.1 2 3 It is not so much a demarcated illness as a quantitative departure from the normal range, defined simply by a daily calcium excretion of above 300 mg (men), 250 mg (women) or 4 mg per kilogram (either sex), normocalcemia and the absence of a particular cause of hypercalciuria such as renal tubular acidosis, sarcoidosis, immobilization, vitamin D excess, hyperthyroidism, glucocorticoid excess of any cause, malignant tumors involving bone, Paget's disease, rapidly progressive osteoporosis and other, rare. © 1979, Massachusetts Medical Society. All rights reserved.