Abstract
A 16-year-old boy with early-childhood-onset retinal dystrophy and developmental delay was diagnosed with abetalipoproteinemia based on ophthalmic examination, history, and results of a peripheral blood smear. The diagnosis was confirmed by lipid profile and genetic testing, and an older sister was confirmed to be affected as well. Although abetalipoproteinemia is treatable in early childhood, most cases are diagnosed late if at all. We highlight clinical features that should raise suspicion for this treatable but likely under-diagnosed form of early-onset retinal dystrophy and document retinal optical coherence tomography findings for a genetically proven case.