Osteoporosis-pseudoglioma syndrome or OPGG is a rare genetic condition characterized by early-onset blindness and severe osteoporosis alongside seemingly random bone fractures.

[1][2] Another very common symptom is total blindness, which usually manifests in two ways: Occasional findings include epilepsy, intellectual disabilities, joint hypermobility, hypotonia,[1] cataracts, microphthalmia, and iris, lens, and vitreous defects.

[3] People with only one copy of the gene mutation involved in this condition (heterozygotes) are at a higher risk of developing exudative vitreoretinopathy and having low bone density, which can consequently result in osteoporosis.

Loss-of-function mutations in the LRP5 protein alter the chemical signaling pathways involved in normal bone formation and retinal development, causing the abnormalities that patients with this condition show.

[3][7] It was first discovered in 1972 by Bianchine et al. when they described three families with osteogenesis imperfecta, pseudoglioma, retinoblastoma, and recurrence of bone fractures.