PEX12 and Leber hereditary optic neuropathy: We present the first Egyptian case with this variant showing bilateral optic atrophy, expanding the known clinical phenotype of PEX12-related PBD.<h4>Case presentation</h4>A six-year-old Egyptian boy, born to first-cousin parents, presented with early hypotonia, developmental regression, visual inattention, and sensorineural hearing loss.