ATM and systemic sclerosis: In analysis of SSc subsets with the HLA-DRB1 allele subtypes (Table 4), DRB1*01∶01 and DRB1*04∶06 were significantly decreased and increased, respectively, in SSc patients who were ACA negative, lcSSc or ATA positive; DRB1*07∶01 and *08∶02 were associated with lcSSc with decreased and increased occurrence, respectively; DRB1*12∶02 was increased in SSc patients with ATA or pulmonary fibrosis; DRB1*15∶02 and *16∶02 represented the major risk alleles for ACA positive and ATA positive SSc, respectively.