CSF Aβ42, Tau and phosphorylated Tau, APOE 4 allele and MCI type in progressive MCI

Background The patients with mild cognitive impairment (MCI) have an elevated risk for Alzheimerʹs disease (AD). Especially the amnestic MCI is seen as prodrome of AD. Apolipoprotein E (APOE) 4 allele, abnormal CSF Aβ42, Tau and phosphorylated Tau (phospho-Tau) levels are associated with elevated risk for AD. Methods APOE genotyping was done by PCR based method and baseline CSF Aβ42, Tau and phospho-Tau were measured by ELISA from 60 controls and 79 MCI patients. Results Thirty-three MCI patients developed dementia during an average of 3.5 years follow-up. CSF Aβ42 was decreased and Tau and phospho-Tau were increased in the progressive MCI patients. The APOE 4 allele was more frequent in the progressive MCI patients. The APOE 4 allele showed a dose dependent association to the Aβ42 levels in the progressive MCI patients and to all of the markers in controls. Conclusions Decreased CSF Aβ42 and elevated Tau or phospho-Tau together with APOE 4 allele are highly predictive for the dementia in MCI patients with amnestic or executive symptoms.