alpha-glucosaminide n-acetyltransferase deficiency (medical condition): A rare inherited biochemical disorder characterized by the accumulation of mucopolysaccharides (glycosaminoglycans) due to deficiency of an enzyme called acetyl-CoA:alpha-glucosamide N-acetyltransferase. Mucopolysaccharide levels build up and are then deposited in various tissues. See also MPS 3 C