As aptly stated forty years ago,1children suffering from progeria present a unique and weird clinical picture of "immaturity upon which has descended the blight of premature senility." This disease, which first becomes manifest at approximately 1 year of age in a previously healthy infant, is characterized by dwarfism, by a loss of hair and of subcutaneous fat and by the precocious development of arteriosclerosis. While excellent clinical descriptions of progeria are available in the literature,2but little information concerning the metabolic status of patients with this disease has been encountered. Because it was believed that such data might cast more light on factors responsible for stunting of growth in children and for the changes of old age, a metabolic study was undertaken on a 6 year old boy with characteristic progeria. THE SUBJECT The patient was a member of an essentially healthy family comprised of the parents