GC and chronic kidney disease: Notably, in the few studies of adults and children with CKD, serum VDBP concentrations were measured using a monoclonal antibody which recognizes a single epitope near the polymorphic region of VDBP and thus show preferential binding to the Gc1S isoform, leading to underestimation of VDBP concentrations that differ by race [28, 33, 34, 40, 41].