Carrying one copy, but not two copies of KL-VS [23], referred to as KL-VS heterozygosity (KL-VShet) leads to the overexpression and increase in the KLOTHO expression levels in the blood and to an increased clearance of Aβ accumulation in the brain decreasing the risk of dementia in those individuals with AD who also carry the APOε4 allele [24]. Here, KL is linked to Alzheimer disease.