Longitudinal findings from differential tractography of patients with type II GM1 gangliosidosis

GM1-gangliosidosis is a rare heritable lysosomal storage disorder caused by accumulation of GM1-ganglioside due to deficiency of the lysosomal enzyme b-galactosidase required for sphingolipid degradation. Progressive accumulation of GM1-ganglioside in the central nervous system induces hypomyelination that results in progressive neurodegeneration. This study used differential tractography in 11 type II GM1 patients to assess longitudinal white matter tract changes using fractional anisotropy (FA) in different regions of the brain in late-infantile and juvenile patients. FA decrease was observed predominantly in the corpus callosum, superior longitudinal fasciculus, and cingulum in supratentorial white matter structures, demonstrating the utility of differential tractography.