Normalization of multiple deficiency of intracellular lysosomal hydrolases in I-cell disease (ICD) fibroblasts by sucrose loading has been reported (Kato et al. (1982) J. Biol. Chem. 257, 7814). Further studies revealed that the effects of sucrose on the induction of hydrolases in seven ICD strains examined in this study were characteristic in each strain. The results may indicate that ICD strains can be classified into subgroups by the degree of enzymic induction. Moreover, this speculation seems to be supported by the normalization of electrophoretic patterns of beta-hexosaminidase in ICD fibroblasts after sucrose loading.