Yet, Tardy et al. reported that the sensitivity of mucolipidosis II fibroblasts to cell death induced by staurosporine, sphingosine or TNF, acquired after these cells were exposed to a mixture of Man-6-P-bearing hydrolases, cannot be reversed by the incubation of the cells with a cathepsin B inhibitor. This evidence concerns the gene CTSB and mucolipidosis type II.