[Familial hypocalciuric hypercalcemia: two case reports (author's transl)].

Two cases of familial hypocalciuric hypercalcemia (FHH) are reported with a review of the literature. Both cases had hypercalcemia, hypophosphatemia, variable parathormone (PTH) levels and hypocalciuria. The parathyroid glands were only slightly hyperplastic and subtotal parathyroidectomy did not reduce the hypercalcemia. FHH is an autosomal dominant congenital disease with high penetrance. It is characterised by hypocalcemia. This contradictory biological finding should alert the physician to the diagnosis and initiate a familial enquiry. The serum PTH and urinary cyclical-AMP levels do not distinguish FHH from primary hyperparathyroidism. Surgery is usually contraindicated because it is ineffective and because the disease is usually benign. Semi-quantitative bone histology in a patient with a high PTH level was normal. The value of bone biopsy in these cases is discussed.