Retinal abnormalities are well documented in patients with ganglioside storage 
diseases. The total content and distribution of retinal glycosphingolipids was 
studied for the first time in control mice and in Sandhoff disease (SD) and GM1 
gangliosidosis mice. Light and electron microscopy of the SD and the GM1 retinas 
revealed storage in ganglion cells. Similar to previous findings in rat retina, 
GD3 was the major ganglioside in mouse retina, while GM2 and GM1 were minor 
species. Total ganglioside content was 44% and 40% higher in the SD and the GM1 
retinas, respectively, than in the control retinas. Furthermore, GM2 and GM1 
content were 11-fold and 51-fold higher in the SD and the GM1 retinas than in 
the control retinas, respectively. High concentrations of asialo-GM2 and 
asialo-GM1 were found in the SD and the GM1 retinas, respectively, but were 
undetectable in the control retinas. The GSL abnormalities in the SD and the GM1 
retinas reflect significant reductions in beta-hexosaminidase and 
beta-galactosidase enzyme activities, respectively. Although electroretinograms 
appeared normal in the SD and the GM1 mice, visual evoked potentials were 
subnormal in both mutants, indicating visual impairments. Our findings present a 
model system for assessing retinal pathobiology and therapies for the 
gangliosidoses.