POLG and anemia: The fact that the premature aging caused by mtDNA mutations can be observed so dramatically in blood samples is also consistent with previous work on the Polgmut/mut model showing that Polg mutation triggers inflammation and alterations in circulating leukocyte populations (Lei et al., 2021; West, 2017) as well as anemia due to the loss of erythrocytes (Ahlqvist et al., 2015; Chen et al., 2009).