Osteoporosis-pseudoglioma syndrome (OPPG; MIM 259770) is an autosomal recessive disorder characterized by early onset vision loss and osteoporosis. Reported eye findings include pseudoglioma, phthisis bulbi, microphthalmia, cataracts, absent anterior eye chambers and various vitreoretinal abnormalities. Individuals lacking vitreoretinal abnormalities may not have osteoporosis-pseudoglioma syndrome. Most patients are blind by 15 years of age. Bone fragility and severe osteoporosis resulting in spontaneous fractures, long bone deformities, short stature, kyphoscoliosis, pseudoarthrosis and platyspondyly have been described. Most cases of OPPG are caused by loss of function mutations in the low density lipoprotein receptor-related protein-5 gene (LRP5). DNA sequencing of the LRP5 gene will define mutations in more than 70% of cases. The findings in OPPG overlap with features of exudative vitreoretinopathy 4 (MIM 601813).