AbstractThe activity of N‐acetyl galactosamine‐6‐sulfate sulfatase was studied for the first time in the liver and brain of a patient with a clinically typical case of Morquio syndrome with keratosulfaturia. As has been demonstrated in the fibroblasts of patients with this syndrome, this enzymatic activity was markedly decreased in both organs.Neuropathological examination revealed moderately swollen neurons containing PAS‐positive, coarse globular inclusions in the cerebral cortex, Ammon's horn, basal ganglia, and thalamic nuclei. Ultrastructurally, the inclusions consisted of stacked, straight or loose, wavy membranes of various lengths, often associated with pale or moderately electron dense homogeneous “lipid droplets.” These ultrastructural features of the inclusions were closely similar to the granulomembranous bodies of Hurler syndrome and the inclusions described in type B of the Sanfilippo syndrome. Unlike those mucopolysaccharidoses, however, no abnormalities were found in the gangliosides in the brain of the patient with Morquio syndrome.