Rachael Gorman in The Scientist:
The retina is layered with photoreceptors, a variety of other neurons, and protective and structural membranes, but retinal disorders can tamper with this delicate system. Mutations in the Crumbs homolog 1 (CRB1) gene disrupt the integrity of retinal membranes, leading to the gradual loss of photoreceptors. CRB1 mutations associate with multiple retinal diseases, including Leber congenital amaurosis and retinitis pigmentosa. However, since each patient’s disease presents differently, with various types, numbers, and locations of retinal lesions, some scientists suspect that environmental factors interact with the CRB1 gene to influence how disease manifests.
A new study published in Cell demonstrated one way that the environment modifies the phenotype of mice with a CRB1 mutation.1 Researchers showed that CRB1 degradation triggers both a leaky colon epithelial barrier and a leaky retinal pigment epithelium (RPE) barrier in the mice, allowing bacteria to pass from the gut into the bloodstream, and then into the eye, damaging the retina.
More here.