As CSF tau and Aβ42 levels have emerged as two biomarkers for early diagnosis of dementia, in this paper, meta-analysis of published studies for CSF tau and Aβ42 level has been carried out to establish the role of combination of two biomarkers in Alzheimer's disease and dementia due to other causes (DOC). Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.