GM2 gangliosidosis; Tay-Sachs Disease: The distended neurons in this photomicrograph from a case of GM2 gangliosidosis or Tay-Sachs Disease are typical of the changes seen in many forms of lipid storage disease. Distention of cytoplasm is caused by an abnormal accumulation of lipid. The underlying biochemical disturbance is a deficiency of the enzyme hexosaminidase, which leads to faulty metabolism of lipids. The ultimate fate of these neurons is degeneration, disintegration, and removal by phagocytes.