In all, 10/12 (83%) sera from patients with MCTD who previously had tested positive for anti-U1-RNP antibodies (ALBIA and/or EUROLINE) were confirmed to be anti-U1-RNP-positive, and 9/12 (75%) were determined to be anti-RNP70 positive with the FEIAs. This evidence concerns the gene SNRNP70 and mixed connective tissue disease.