The invention discloses using secreted splicing variant of mammal Klotho (s-KL) as an agent for the prevention N and/or treatment of cognitive and/or behaviour impairments. It also refers to gene constructs and expression vectors useful in gene therapy for the delivery of said s-KL variant to the central nervous system of a mammal, in particular a rodent or a human. Pharmaceutical compositions comprising either the protein s-KL or any gene construct for expressing the protein in the CNS are also disclosed.