Indeed, pathogenic variants of ADPRHL2, encoding the mono(ADP-ribosyl) hydrolase ARH3, have been found in individuals exhibiting neurodegenerative symptoms including cerebellar atrophy and progressive ataxia, a disorder now termed childhood-onset neurodegeneration, stress-induced, with variable ataxia and seizures (CONDSIAS) (see Bannister et al.85 and references therein). This evidence concerns the gene ADPRS and cerebellar ataxia.