From OMIMBietti crystalline corneoretinal dystrophy (BCD) is an autosomal recessive retinal dystrophy characterized by numerous tiny glistening yellow-white crystals at the posterior pole of the retina, associated with atrophy of the retinal pigment epithelium (RPE), pigment clumps, and choroidal sclerosis. Most cases have similar crystals at the corneoscleral limbus. The disorder is progressive; most patients develop decreased vision, nyctalopia, and paracentral scotomata between the second and fourth decades of life. Patients later develop peripheral visual field loss and marked visual impairment, usually progressing to legal blindness by the fifth or sixth decade of life. In a series of European patients diagnosed with nonsyndromic retinitis pigmentosa (RP; see 268000), BCD accounted for approximately 3% of all nonsyndromic RP and 10% of nonsyndromic autosomal recessive RP. Histopathology shows advanced panchorioretinal atrophy, with crystals and complex lipid inclusions seen in choroidal fibroblasts, corneal keratocytes, and conjunctival and skin fibroblasts, as well as in circulating lymphocytes, suggesting that BCD may result from a systemic abnormality of lipid metabolism (summary by Li et al., 2004).
http://www.omim.org/entry/210370