PDRG1, also known as PDRG or C20orf126, is a 133 amino acid protein that localizes to the cytoplasm and belongs to the prefoldin subunit β family. Expressed predominately in normal testicular tissue, PDRG1 is functionally induced by ultraviolet light and is thought to play a role in chaperone-mediated protein folding, possibly playing a role in cellular degradation. It is associated with Creutzfeldt-Jakob disease, amyotrophic lateral sclerosis, spinal muscular atrophy, ring chromosome 20 epilepsy syndrome and Alagille syndrome.