Looking chloride channels straight in the eye: Bestrophins, lipofuscinosis, and retinal degeneration

Recent evidence suggests that Cl- ion channels are important for retinal integrity. Bestrophin Cl- channel mutations in humans are genetically linked to a juvenile form of macular degeneration, and disruption of some ClC Cl- channels in mice leads to retinal degeneration. In both cases, accumulation of lipofuscin pigment is a key feature of the cellular degeneration. Because Cl- channels regulate the ionic environment inside organelles in the endosomal-lysosomal pathway, retinal degeneration may result from defects in lysosomal trafficking or function.