SOST and Alzheimer disease: Results were correlated with AD biomarkers, amyloid beta (Aβ) 42, phosphorylated tau (p-tau), and total tau (t-tau), and clinical parameters of dementia severity.<h4>Results</h4>CSF sclerostin increased in patients with dementia due to AD and correlated negatively with Aβ42 and positively with p-tau, t-tau, and dementia severity.<h4>Discussion</h4>The association of CSF sclerostin with Aβ42, tau pathology, and dementia severity in the early disease stages is of great clinical relevance for the identification of sclerostin as a promising biomarker in early AD stages.