Centromeric SGO2 surrounds, but does not overlap, the two sister centromeres/inner kinetochores (as identified by calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia [CREST] or CENP-C staining), forming cup-like structures that are frequently connected by a SGO2 bridge (Figure 1B). This evidence concerns the gene CENPC and esophagitis.