Hyperparathyroidism, Neonatal Self-Limited Primary, With Hypercalciuria

Among the children of healthy, nonconsanguineous Japanese parents, Nishiyama et al. (1990) described 3 sibs, a boy and 2 girls, with hypercalciuria, nephrocalcinosis, and renal tubular acidosis. All 3 demonstrated an exaggerated response of serum parathyroid hormone to serum calcium and higher elevations of serum calcium with oral calcium loading. Hypercalcemia associated with the abnormal response of parathyroid hormone secretion disappeared after the age of about 2 years, although renal tubular acidosis and nephrocalcinosis remained. Autosomal recessive inheritance was suggested. The disorder in the first sib was diagnosed at age 4 months when the boy showed failure to thrive and vomiting. None of the sibs had facial or cardiac features of Williams syndrome. The second affected sib was diagnosed at the age of 2 months. In the third, nephrocalcinosis was suspected in utero because of high echo densities in the kidney. The diagnosis of hypercalcemia accompanied by metabolic acidosis was confirmed at the age of 5 days.