ATG4D and mucolipidosis type II: However, recent research has shown that the limiting membrane of the storage compartments can be more diverse, as is the case in mucopolysaccharidosis IIIB,30 where the membranes derive from the Golgi apparatus, and in multiple sulfatase deficiency and in mucolipidosis type II, where they represent compartments of the autophagy pathway, namely, autophagosomes and autolysosomes.6,23 The ATG4D-linked phenotype in Lagotto Romagnolo dogs adds to this group, as the main histopathological finding is accumulating intracellular vacuoles that are not solely of lysosomal origin.