Hexosaminidase Activities in a Case of Systemic G M2 Gangliosidosis of Late Infantile Type

Abstract

Summary

An unusual systemic G_M2 gangliosidosis of late infantile type was shown to have high levels of hexosaminidase activity in brain and liver. It, therefore, differs from another G_M2 variant of late infantile type reported by Sandhoff et al. (2), in which hexosaminidase activity was absent.

Addenum. Okada and O'Brien reported that the isoenzyme hexosaminidase A was absent in TSD tissue (6). The percentage of hexosaminidase A and B in brain extracts from the present case and from a TSD and control case were analyzed by acrylamide gel electrophoresis and quantitative fluorometric scanning using 4-methylumbelliferyl-2-acetamide-2-deoxy-β-D-glucopyranoside as substrate. In the present case the A fraction comprised 40% of the total hexosaminidase activity in contrast to 60% in a control and 0% in TSD brain.