Recently, Ito et al. verified whether the cutoff value of 30 pg/mL could also be applicable for the CL-Jack iFGF23 assay and concluded that it leads to a sensitivity of 100% and specificity of 82% for FGF23-related hypophosphatemic rickets with and without vitamin D deficiency [59]. This evidence concerns the gene FGF23 and hypophosphatemic rickets.