Abstract
Skin punch biopsies of six children suffering from infantile or late onset Tay-Sachs disease, juvenile Sandhoff disease, or GM gangliosidosis type I, contained axons which, when viewed with the electron microscope, were distended by large amorphous black deposits. These are nonspecific residual bodies. Their large numbers indicate severe disturbance of the nerve cell and may be part of the dying back process. The three cases with Tay-Sachs disease had also axonal zebra or complex membranous bodies which appeared to be specific. Cytoplasmic vacuolation of other cells was a feature in the patient with GM1 gangliosidosis. Biopsies of three parents were negative.