EC Neurology

Metachromatic leukodystrophy (MLD) is a progressive lysosomal storage disorder in which brain magnetic resonance imaging (MRI) may provide the first clue to an inherited white matter disease. We report a 6-year-old girl with developmental delay from early life, a history of minor perinatal distress with an otherwise reassuring neonatal course, longstanding spasticity, inability to walk independently, and caregiver-reported developmental regression beginning at approximately 18 months of age. She had previously been labeled as having cerebral palsy and was referred for brain MRI after epileptic seizures. MRI demonstrated bilateral, symmetric, confluent T2- and fluid-attenuated inversion recovery hyperintensity of the periventricular and deep cerebral white matter, most pronounced in the parieto-occipital regions with frontal involvement and relative sparing of the subcortical U-fibers, without corresponding diffusion restriction. This distribution suggested an inherited leukodystrophy, particularly MLD. The diagnosis was subsequently confirmed biochemically by reduced leukocyte arylsulfatase A activity together with increased urinary sulfatide excretion, the latter distinguishing true enzyme deficiency from arylsulfatase A pseudodeficiency. Molecular testing was not performed but is recommended for family genetic counseling. This case illustrates that true developmental regression is not a feature of the static encephalopathy underlying cerebral palsy and should prompt renewed investigation, and that a characteristic MRI pattern can direct the biochemical testing required to confirm MLD.

Keywords: Metachromatic Leukodystrophy; Developmental Regression; Epilepsy; Magnetic Resonance Imaging; Cerebral Palsy

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