[1] Univ Oslo, Dept Clin Mol Biol, N-1478 Lorenskog, Norway
[2] Akershus Univ Hosp, N-1478 Lorenskog, Norway
[3] Harvard Med Sch, Dept Genet, Boston, MA 02115 USA
[4] Univ New South Wales, Sch Med Sci, Dept Pharmacol, Sydney, NSW 2052, Australia
[5] Johns Hopkins Univ, Dept Neurosci, Sch Med, Baltimore, MD 21205 USA
[6] Norwegian Ctr Hlth Ageing NO Age, Oslo, Norway