Gangliosidosis GM1 is due a deficiency of lysosomal acid beta-galactosidase which gives sphingolipids (GM1) accumulation. It has systemic compromise, mainly neurologic disease and organomegaly. Here, We report a 5-years old child with a juvenile presentation or type II, which is characterized by regression of neurodevelopment and progression to neurodegeneration. Based in his laboratory, neuroimaging and low enzymatic activity of beta-galactosidase a diagnosis of gangliosidoses GM1 was made.