The typical dental finding diagnostic of CLS in children is the premature loss of teeth.14–17,28 This is partially phenocopied in Rsk2-deficient mice, which show an increased loss of alveolar bone.18 In this study, we also observed this horizontal alveolar bone loss around maxillary molars that were not subjected to tooth movement. The gene discussed is RPS6KA3; the disease is Coffin-Lowry syndrome.