However, GM3 increase in the brains of Neu3/Neu4 double-KO mice was relatively modest as compared with those caused by deficiencies of the essential ganglioside hydrolases such as β-galactosidase (GM1 gangliosidosis) or β-hexosaminidases A and B (GM2 gangliosidosis), suggesting the existence of alternative catabolic pathways. This evidence concerns the gene NEU4 and GM1 gangliosidosis.