In another study, serum concentrations of DKK1 and RANKL were found to be elevated in a series of 18 children with OI (both untreated and after treatment with neridronate) leading the authors to conclude that these cytokines may play a role in causing increased bone resorption and reduced one formation in OI (12). This evidence concerns the gene DKK1 and osteogenesis imperfecta.