Human alpha-mannosidosis is a lysosomal storage disorder characterized
by mental retardation, dysostosis multiplex, and hepatosplenomegaly.
Deficiency of the enzyme leads to accumulation of mannose-rich glycoco
njugates in tissues. Zinc sulphate has been shown to stimulate alpha-m
annosidase activity in vitro. Oral zinc therapy was attempted on a 4-y
ear-old boy with alpha-mannosidosis for 3 years. After almost 10 years
of follow-up on and off zinc therapy, we must conclude that oral zinc
does not substantially affect the clinical course of alpha-mannosidos
is.