Metachromatic Leukodystrophy (MLD)

Abstract

METACHROMATIC leukodystrophy (MLD) is characterized by deficient activity of sulfatase A (arylsulfatase A; cerebroside sulfatase) and by a corresponding accumulation of cerebroside sulfate. The disease begins at different ages and evolves at different tempos. Late infantile, juvenile, adult, and variant forms occur. Each form tends to have subtly different clinical, neuropathological and chemical findings. How is one to explain the variation within this model disease? Are there any principles which, by extension, might give us a better understanding of the pathogenesis of other diseases? To begin to answer these questions we have started to characterize the minute amounts of enzyme activity which still remain in MLD. Three aspects of sulfatase A have been studied: (1) the amount of sulfatase A activity present; (2) the kinetic parameters of the enzyme; and (3) the effect on the enzyme activity of various compounds known to interact with enzyme proteins. The purposes of