Mucopolysaccharide storage disease type I (Hurler)

At first almost inapparent, the early signs of the
disease occur at about 1–2 years of age, with increasing
coarsening of the facial features, retarded
mental development, limited joint mobility,
enlarged liver, umbilical hernia, and other
Classification of the mucopolysaccharide storage diseases (MPS)
MPS Type Enzyme Defect Important Manifestations
IH (Hurler) !-L-Iduronidase Dysostosis multiplex, severe
developmental disorder, corneal clouding
IS (Scheie) !-L-Iduronidase Stiff joints, corneal clouding, normal
mental development
II (Hunter)
(X-chromosomal)
Iduronate sulfatase Dysostosis multiplex, no corneal clouding,
developmental retardation
III (Sanfilippo)
A Heparan N-sulfatase Severe psychomotor retardation beginning
about age 6–8 years, relatively mild
somatic signs.
B !-N-Acetylglucosaminidase
C Acetyl-CoA: !-glucosaminide
N-acetyltransferase
D N-acetylglucosamine-6-
sulfate sulfatase
IV (Morquio)
A Galactose-6-sulfatase Corneal clouding, severe skeletal
changes, short stature,
B "-Galactosidase odontoid process hypoplasia, normal
mental development
VI (Maroteaux–Lamy) N-acetylgalactosamine-4-
sulfatase
(aryl-sulfatase B)
Dysostosis multiplex, corneal clouding,
normal mental development
VII (Sly) "-Glucuronidase Dysostosis multiplex, corneal clouding
(After McKusick, 1998)
signs. Radiographs show coarsening of skeletal
structures (dysostosis multiplex). The photographs
show the same patient at different ages
(own data).