Targeted single deletions in mouse of various genes such as Fanca, Fancc, Fancd2, and Fancg exhibit decreased long term HSC repopulating activity and germ cell loss in addition to cellular sensitivity to DNA interstrand crosslinks and oxidative stress, but lack the clinical characteristic of FA including marrow aplasia, hematological abnormalities, and early life tumorigenesis 28, 29, 30, 31, 32, 33. This evidence concerns the gene FANCA and Friedreich ataxia.