Our findings contrast with Grøndvedt et al., who reported a positive association of CSF sαKl with CSF Aβ42 and a negative association with CSF T-tau and P-tau, while plasma sαKl only correlated negatively with CSF T-tau and P-tau.4 Ren et al. observed a negative correlation between plasma Klotho and CSF Aβ42, but not any of the other investigated CSF biomarkers (T-tau, P-tau181, NfL) in a mixed sample of cognitively unimpaired individuals and AD patients,24 suggesting that higher sαKl levels are associated with greater Aβ accumulation and potentially more advanced AD pathology. This evidence concerns the gene KL and Alzheimer disease.