Figure 1.

Age-related changes in DNA repair and their consequences. Inefficient MMR leads to microsatellite instability, point mutations and potentially, to increased frequency of LOH. Decline in efficiency and fidelity of BER and NER leads to point mutations. Less efficient and more error-prone NHEJ results in point mutations and genomic rearrangements. As fewer cells are in G2 stage, the usage of sub-pathways of DSB repair (DSBR) may also change, where precise HR between sister chromatids declines, giving way to more mutagenic SSA and mitotic recombination (MR) with homologous chromosome leading to genomic instability and LOH.