Poretti-Boltshauser Syndrome in a Toddler: Novel Neuroimaging Features and Clinical Presentation.

Poretti-Boltshauser syndrome (PBS) is a rare autosomal recessive disorder characterized by cerebellar dysplasia with cysts, developmental delay, and ocular abnormalities. We present a one-year-old male with developmental delay, hypotonia, and abnormal eye movements. Brain magnetic resonance imaging revealed extensive cerebellar dysplasia with multiple cortical and subcortical cysts, an enlarged rhomboid-shaped fourth ventricle, and splayed superior cerebellar peduncles. Genetic testing confirmed compound heterozygous pathogenic variants in the LAMA1 gene, both classified as pathogenic according to American College of Medical Genetics and Genomics (ACMG) guidelines. This case highlights the distinctive neuroimaging pattern of PBS, which can guide early diagnosis and appropriate genetic testing. Recognition of these imaging features is crucial for pediatric radiologists, as early diagnosis enables timely intervention with supportive therapies and genetic counseling for affected families.