SOD1 and GM2 gangliosidosis: For example, patients with partial deficiency of hexosaminidase A enzyme activity (also known as GM2 gangliosidosis, a form of sphingolipidosis) may have clinical manifestations mimicking ALS.26 The accumulation of ceramides and cholesterol esters also occurs within the spinal cords of patients with ALS and an SOD1 transgenic mouse model of ALS.27