A recent discovery in the news is the Klotho gene which seems boost brain function and adds to longevity. About one in five people have the good variant.

If you tested at 23andme, you can find out if you have it by checking the SNP at rs9536314, the protective variant is the heterozygous one, GT, while the normal variant is TT. The homozygous version, GG, appears to be deleterious.

So log into your 23andme account and then click this URL to see if you have the GT  version is
https://you.23andme.com/tools/data/?query=rs9536314&filter_by_platforms=true

Here are a few informative news articles explaining this discovery:
http://www.ucsf.edu/news/2014/05/114196/better-cognition-seen-gene-variant
http://www.medicalnewstoday.com/articles/276665.php

Now to get more technical.

Here are a few more techical links
http://en.wikipedia.org/wiki/Klotho_(biology)
http://www.genecards.org/cgi-bin/carddisp.pl?gene=KL

On the GENEALOGY-DNA group at Rootsweb our resident expert Ann Turner looked into this for us and said

“The full text for the technical article, [subscription required], is here:

http://www.cell.com/cell-reports/fulltext/S2211-1247(14)00287-3)

The nomenclature for this variant seemed odd to me, so I searched further
back in the literature and found an explanation dated 2001. It turns out to
be a haplotype (a set of variants on one chromosome). This old article does
state that the markers are in complete linkage disequilibrium in their
study population. If that holds up in subsequent studies, then a G for
rs9536314 would predict a C for rs9527025, and you would have the KL-VS
variant.

http://www.pnas.org/content/99/2/856.long

“These results precipitated a search for functional variants of klotho. We
identified an allele, termed KL-VS, containing six sequence variants in
complete linkage disequilibrium, two of which result in amino acid
substitutions F352V and C370S.”

Note also that the homozygous version of the KL-VS variant appears to be
detrimental.