Biomarkers of Alzheimer Disease Observed in Down Syndrome

Tau proteins
Tau proteins
Neurological and neuropsychological examinations were performed to assess intellectual disabilities, and biological assays were performed on collected CSF and plasma.

Findings from a recent cross-sectional, single-site study highlight potential diagnostic biomarkers of Alzheimer disease-related neurodegeneration in Down syndrome. The study was published in The Lancet Neurology.

Researchers sought to determine whether biomarker (ie. NfL, Ab1-40, Ab1-42, t-tau, p-tau) concentrations in the cerebrospinal fluid (CSF) and plasma would have diagnostic potential in detecting either prodromal Alzheimer disease (AD) or AD dementia in Down syndrome. The convenience sample (n=469) consisted of adult participants with Down syndrome in 1 of 3 categories: asymptomatic (n=194), prodromal AD (n=39), and AD dementia (n=49). Neurological and neuropsychological examinations were performed to assess intellectual disabilities, and biological assays were performed on collected CSF and plasma.   

Data showed that NfL, Ab1-40, and Ab1-42 plasma concentrations were higher in all Down syndrome cohorts in comparison with controls (all P <.0001). Also, t-tau concentrations in the plasma were higher in the  AD dementia group in comparison with controls. The researchers showed that NfL (P =.0001), Ab1-40 (P =.02), and t-tau (P =.0003) plasma concentrations were highest in the AD dementia group in comparison with the asymptomatic and prodromal AD groups. Results showed controls had higher levels of CSF concentrations of Ab1-42. NfL, t-tau, and p-tau CSF concentrations were higher in prodromal AD and AD dementia cohorts than in controls.

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Study limitations include the cross-sectional collection period for sample analysis and a need for validation of findings on a multicenter level.

These findings suggest that the differing concentration levels of various biomarkers can be determined and utilized in the diagnosis for AD-related neurodegeneration in Down syndrome patients.

Disclosures: Please refer to original reference for a full list of authors’ disclosures.

Reference

Fortea J, Carmon-Iragui M, Benejam B, et al. Plasma and CSF biomarkers for the diagnosis of Alzheimer’s disease in adults with Down syndrome: a cross-sectional study [Published online August 29, 2018]. Lancet Neurol. doi: 10.1016/S1474-4422(18)30285-0