Patients with SLE were stratified according to the age of onset ( < 20 years or ≥ 20 years), presence of renal disorders, neurological disorders, anti-dsDNA, anti-Sm and anti-RNP antibodies, and patients with SSc according to diffuse cutaneous SSc (dcSSc) or limited cutaneous SSc (lcSSc), presence or absence of anti-topoisomerase I antibody (ATA), anti-centromere antibody (ACA), and interstitial lung disease (ILD), and case-case analysis was performed. Here, ATM is linked to systemic sclerosis.