PCNA has a central role in DNA replication, repair, and chromatin dynamics, as illustrated by a mutation in human PCNA associated with DNA repair deficiency syndrome akin to diseases like xeroderma pigmentosum, Cockayne syndrome, and ataxia telangiectasia (Baple et al., 2014, Duffy et al., 2016). This evidence concerns the gene PCNA and Ataxia-telangiectasia.