Ultrastructure of cultured fibroblasts in mucolipidosis type IV.

Five patients have been classified as suffering from mucolipidosis type IV on the basis of the findings in various tissues and in cultured fibroblasts. The light and electron microscopic features of cultured fibroblasts in this disease are described in detail. The differentiation of this condition from other lysosomal storage diseases and other types of mucolipidoses is discussed. The importance of identifying this disease for purposes of intrauterine diagnosis and eventual understanding of the underlying enzyme defect is stressed.