RORA and cerebellar ataxia: RORα is expressed broadly, notably in skeletal muscle, liver, kidney, lungs, adipose tissue, skin, and brain.61Rora KO (Rora−/−) andstaggerer mutant (Rorasg/sg) mice displayed debilitating cerebellar ataxia and are mostly infertile.52,71,80,81 RORα-deficient mice also showed a multitude of other defects including thin long bones82 and abnormal retinal development,83,84 the latter corresponding to high expression levels of RORα in the ganglion cell layer, the inner nuclear layer, and cone photoreceptors in the outer layer.