In Alzheimer’s disease (AD), KLK6-8 and 10 have been suggested as AD biomarker candidates, with CSF studies indicating elevated KLK6 and KLK10 in biomarker-confirmed cases, while KLK8 remains largely unchanged and KLK7 is decreased [107,236,245]. This evidence concerns the gene KLK6 and early-onset autosomal dominant Alzheimer disease.