A case of McCune-Albright syndrome with hyperthyroidism and vitamin D-resistant rickets

A girl aged 1 11/12 year with the unusual combination of McCune-Albright syndrome (polyostotic fibrous dysplasia, cutaneous pigmentation and precocious puberty), hyperthyroidism and vitamin D-resistant rickets is described. Urinary estrogens are increased, while serum LH and FSH responses to LH-RH are subnormal. Thyroid hormone levels in serum and 131I thyroidal uptake are increased, while TSH response to TRH is decreased. Serum phosphorus level is low and phosphate clearance high, while PTH is within normal range. Basal GH level and GH responses to various stimulations are high, but high basal GH is suppressed by oral glucose. The oral glucose tolerance test shows normal blood glucose with hypersecretion of insulin. These data suggest that the common pathogenesis of the various aspects of the syndrome is a hypersensitivity of the target organs, which include the pituitary, the thyroid, the gonads, the pancreatic islet cells and the proximal tubules of the kidney.