Ganglioside G(M2) n-acetyl-β-D-galactosaminidase activity in cultured fibroblasts of late-infantile and adult G(M2) gangliosidosis patients and of healthy probands with low hexosaminidase level

E. Conzelmann, H. J. Kytzia, R. Navon, K. Sandhoff

Research output: Contribution to journalArticlepeer-review

Abstract

A sensitive assay was developed to assess the ability of extracts from cultured fibroblasts to catabolize ganglioside G(M2), in the presence of the natural activator protein but without detergents. This method, which permitted the reliable determination of residual acivities as low as 0.1% of normal controls, was then used to measure ganglioside G(M2) hydrolase activities in fibroblasts from several hexosaminidase variants. The residual activities thus determined correlated well with the clinical status of the respective proband: infantile Tay-Sachs (0.1% of normal controls), late-infantile (0.5%), and adult G(M2) gangliosidoses (2%-4%) and healthy probands with 'low hexosaminidase' (11% and 20%). In contrast, β-hexosaminidase A levels as measured with the synthetic substrate 4-MU-GlcNAc could not be relied on for diagnostic purposes (the late-infantile patient studied retained 80% of the activity of controls).

Original languageEnglish
Pages (from-to)900-913
Number of pages14
JournalAmerican Journal of Human Genetics
Volume35
Issue number5
StatePublished - 1983
Externally publishedYes

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