Metachromatic leukodystrophy (MLD) is an autosomal
recessive condition presenting with progressive psychiatric, cognitive, and pyramidal features. Peripheral nerve
demyelination is frequently found. The MRI
changes have a posterior predominance and
subcortical pattern.

Metachromatic leukodystrophy (MLD) is a lysosomal
storage disease caused by a deficiency
of the catabolic enzyme arylsulfatase A. Inheritance
of the disease is autosomal recessive (1).
It is known as the most common hereditary
leukodystrophy, with a prevalence of one in
100 000 newborns (2). Deficiency of arylsulfatase
A results in accumulation of a metachromatic
lipid material, galactosylceramide sulfatide,
in the white matter of the peripheral and
central nervous system (2), which undergoes
symmetric demyelination with initial sparing of
the subcortical U fibers (3). Many magnetic resonance
(MR) imaging features of MLD have
been described, including symmetric confluent
demyelination of the periventricular white matter
and centrum semiovale with sparing of the
subcortical arcuate fibers, frontal predominance
and frontooccipital progression of demyelination,
subcortical white matter involvement with
corticosubcortical atrophy in the later stage, low
signal intensity in the thalami on T2-weighted
images, involvement of the cerebellar white
matter, and absence of contrast enhancement
of the lesion (1–8).