Poly(ADP-ribose) synthesized after DNA damage is only present transiently and is rapidly degraded by poly(ADP-ribose) glycohydrolase. Poly(ADP-ribose) metabolism is required for maintenance of the normal function of neuronal cells. [(1''->2')-ADP-alpha-D-ribose](n) + H2O = [(1''->2')-ADP-alpha-D-ribose](n-1) + ADP-D-ribose Progressive neurodegeneration (PubMed:14676324). Knockdown of Parg leads to decreased survival when animals are exposed to stress with either hydrogen peroxide or environmental hypoxia (PubMed:30100084). Belongs to the poly(ADP-ribose) glycohydrolase family. Extended N-terminus.