Analysis of the cell lines derived from MSD mice and their wild-type littermates show a decrease in the colocalization of the lysosomal marker, LAMP-1, and LC3 in MSD mouse embryonic fibroblasts (MEFs) [40,47], and the accumulation of autophagosomes resulting from impaired fusion of autophagosomes with lysosomes. This evidence concerns the gene MAP1LC3A and mucosulfatidosis.