Additionally, anti-Scl-70 and anti-centromere antibody positivity rates were higher in SSc patients (anti-Scl-70: p < 0.000; anti-centromere: p = 0.03), whereas anti-RNP positivity was more prevalent in MCTD patients (42.86% vs. 12.32%, p < 0.000). Here, RNPC3 is linked to mixed connective tissue disease.