SSB and systemic lupus erythematosus: In identification of potential CNVs in pSS, we found that some genes in the CNV deletion regions were significantly associated with systemic lupus erythematosus, such as TNF in chromosome 6 and SSB in chromosome 2 in pedigrees A. It is noted that SSB gene in the CNV deletion region in chromosome 2 screened in also existed in pedigree B. Furthermore, SSB was down-regulated in pSS in the differentially expression analysis, which was validated by qPCR.