ADP-ribose glycohydrolase 3 (ARH3) is an enzyme that in humans is encoded by the ADPRHL2 gene.This enzyme reverses the proteins’ post-translational addition of ADP-ribose to serine residues as part of the DNA damage response The enzyme is also known to cleave poly(ADP-ribose) polymers, 1''-O-acetyl-ADP-ribose and alpha-NAD+ Loss-of-function mutations in the ADPRHL2 gene result in a recently defined disorder called stress-induced childhood-onset neurodegeneration with variable ataxia and seizures (CONDSIAS; OMIM: 618170). The CONDSIAS is an autosomal recessive disorder which its pertinent gene (ADPRHL2) is mapped on chromosome 1p35.3-p34.1. The phenotypes of this disorder have been reported as neurodegeneration, variable ataxia and seizures, tremor, nystagmus, balance problems, cerebellar,