Among the progressive deteriorating diseases of infancy and childhood, some of which have been dealt with by us in three earlier publications,1-3 a group of conditions associated with the appearance of calcifications in the brain deserves special attention. Calcifications in the brain occasionally found in infants or appearing gradually during childhood are associated with various conditions, some of which have firmly established clinical-anatomical patterns: tuberosclerosis, angiomatosis (Sturge-Weber syndrome), toxoplasmosis, hypoparathyroidism, cytomegalic inclusion-body disease, cysticercosis, and certain tumors. Another group of cases with a very particular form of intracranial calcifications has been classified as idiopathic nonarteriosclerotic calcifications of the brain. It is often referred to as "Fahr's disease." There may, however, be reasonable objections to this eponym because the condition has been known since Virchow's time and long before Fahr. Recently we were able to study two families in which three and two siblings respectively were affected. In each family,