ATM and ataxia telangiectasia: In contrast to the severe reduction of ASCIZ levels in an ataxia telangiectsia (AT) fibroblast line reported by Kanu and Behrens (2007), we did not detect any loss of ASCIZ in another human AT patient-derived fibroblast cell line (Figure 4B, left panel, AT2221JE) that is considered to be bona fide ATM-deficient [23] compared to control fibroblasts (Figure 4B, left panel, GM847) or the isogenic AT cell line reconstituted with WT Atm (Figure 4B, left panel, AT2221JE+ATM [23]).