Seven families affected with Hurler's syndrome have been studied using the methods of cell culture. Skin fibroblasts obtained from the skin of 7 patients with Hurler's syndrome contained metachromatic granules when stained for mucopolysaccharides with toluidine blue O and alcian blue, whereas fibroblasts from normal subjects contained no metachromatic granules.
In four families skin cultures of the clinically normal parents showed fibroblasts which contained demonstrable metachromatic granules and "gargoyle" cells and were considered to be heterozygous for the abnormal gene. Fibroblast cultures from certain other members of these families showed metachromasia. These findings were also considered to indicate heterozygosity for the abnormal gene.
Three families of the X-linked type of the disease were studied. Fibroblasts cultured from the father contained no metachromatic granules whereas those of the hemizygous mother contained both metachromatic granules and "gargoyle" cells. In one family the abnormal gene could be traced through unaffected individuals for three generations. The prolonged preservation of the biochemical trait in tissue culture will permit studies to be performed designed to clarify the primary action of the abnormal genes which result in Hurler's syndrome, as well as to increase the usefulness of this trait in mapping the human X chromosome.