Distinct Brain Magnetic Resonance Imaging (MRI) Findings Across Mucopolysaccharidosis Types: Novel Insights

IntroductionMucopolysaccharidosis represents a severe lysosomal storage disorder wherein glycosaminoglycans accumulate because of various rare enzyme deficiencies. Magnetic resonance imaging (MRI) plays a crucial role in identifying neurologic involvement and monitoring disease progression.ObjectiveThis retrospective, cross-sectional study aimed to evaluate brain MRI findings in pediatric patients diagnosed with mucopolysaccharidosis, characterizing imaging patterns across subtypes.MethodsEighty pediatric patients with mucopolysaccharidosis who underwent brain MRI between 2010 and 2022 were retrospectively analyzed. MRI features such as enlarged perivascular spaces, ventriculomegaly, atrophy, white matter lesions, optic nerve sheath enlargement, and the newly described "bat sign" were evaluated. Findings were compared across mucopolysaccharidosis subtypes and age groups.ResultsThe most frequent abnormalities were enlarged perivascular spaces (67.5%), ventriculomegaly (46.2%), and atrophy (43.8%). The novel "bat sign" was identified in 49 patients (61%). Enlarged perivascular space was seen in all type I, II, and IIIC patients. Type VI patients had the highest corpus callosum area (P < .001). Brain atrophy was most common in type IIIB patients.ConclusionMRI is a valuable tool for detecting central nervous system involvement in mucopolysaccharidosis. Recognizing these patterns may facilitate early diagnosis and guide therapeutic decisions.