Discussion: Mucopolysacchridosis
Lysosomal storage disorder resulting from deficient enzyme
GAGs deposits in lysosomes and interfere with degradation
GAGs accumulate in cells and excreted in urine
Clinical features - varies with type
most patients have macrocephaly
developmental retardation - prominent in type I, II, III, and VII
skeletal involvement prominent in types IV and VI
Imaging features
general - delayed myelination, atrophy, varying degrees of hydrocephalus
white matter changes
CT - diffuse low attenuation w/i cerebral white matter
MR - diffuse areas of T1 & T2 prolongation
sharply defined foci in corpus callosum, basal ganglia, and cerebral white matter
iso to CSF on all sequence
enlarged perivascular (Virchow-Robin) spaces
progress to become larger and more diffuse like leukodystrophy
atrophy & white matter changes earliest in type I, II, III, and VII
later in life in type IV and VI
spinal abnormality - may lead to cord compression
frequently occurs in type IV and VI
C1-2 atlantoaxial subluxation
from laxity of transverse ligament or hypoplasia/absence of odontoid
chronic subluxation may lead to ligamentous hypertrophy
MR - shortened odontoid w/ soft tissue mass
C1 and C2 dural thickening
thoracic vertebral body gibbus deformity (Morquio most common)