While anti-SSA and anti-SSB antibodies are characteristic of Sjögren's syndrome, the presence of anti-centromere antibodies (typically associated with limited systemic sclerosis) and anti-U1RNP (anti-U1 ribonucleoprotein) antibodies (associated with mixed connective tissue disease) suggests an autoimmune overlap syndrome. This evidence concerns the gene SNRNP70 and Sjogren syndrome.