Morphology of the gangliosidoses.

GM1 and GM2 gangliosidoses are progressive neurodegenerative diseases which accumulate intralysosomal gangliosides--and to a lesser extent oligosaccharides--chiefly in the central and peripheral nervous system owing to deficiencies of beta-galactosidase and hexosaminidases A or/and B, respectively. This intralysosomal "storage" in neuronal pericarya and their processes, and subsequent loss of such nerve cells provide the background for clinical symptoms of the central nervous system and the retina, while involvement of the peripheral nervous system and the visceral organs largely remains free of clinical findings. The morphological involvement of the latter organs is widespread though varying, thus allowing morphological investigations of lymphocytes, skin, or rectum for morphological diagnosis and as a screening procedure.