Adult Polyglucosan Body Disease Presenting with Visual Snow as the Initial Symptom

Adult polyglucosan body disease is an ultra-rare genetic disease caused by variants in the GBE1 gene, typically presenting with neurogenic bladder, spastic paraplegia, and distal sensory neuropathy. This report highlights a case of adult polyglucosan body disease which is both genetically and clinically unique. A 56-year-old male presented for progressive visual changes. He described initial painless discomfort with environmental light evolving to persistent visual snow, particularly upon light exposure. His exam revealed bilateral gluteus medius weakness and a distal sensory neuropathy. MRI of the orbits, brain, and spinal cord revealed bilateral atrophy of the optic nerves, tracts, and optic chiasm; pontine White matter changes and extensive supratentorial leukoencephalopathy; and decreased caliber of the cervical spinal cord. A genetics panel for leukoencephalopathy revealed a pathogenic variant and likely pathogenic variant within GBE1. This report details an infrequently reported, likely pathogenic variant within GBE1 with a unique initial phenotype in this disease.