Morquio B disease was found in a 15-year-old Japanese boy who presente
d with progressive generalized skeletal dysplasia without neurological
manifestations. Mild keratan sulfaturia was found, and P-galactosidas
e was deficient in fibroblasts. Gene analysis revealed two mutant alle
les, (83)Tyr-->His (Y83H) and (482)Arg-->Cys (R482C). The former expre
ssed a low enzyme activity (2-5% of normal), and the latter expressed
no detectable enzyme activity.