To address this apparent discrepancy, we selected13 SSc+ patientsera with discordant ATA assessments (ATA+ by conventional IP, DID*,or commercial ELISA, but ATA– by our custom DID) for analysisby IP-to-MS (Table 1, P1–P8, P10, P12, P13, P15, and P16; and Table S2). This evidence concerns the gene ATM and systemic sclerosis.