[1] Univ Newcastle Upon Tyne, Sch Med, Dept Neurol, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England
[2] MRC, Dev Ctr Clin Brain Aging, Newcastle Upon Tyne, Tyne & Wear, England
[3] Univ Texas, Med Branch, Dept Radiat Oncol, Galveston, TX 77550 USA
[4] Univ Texas, Med Branch, Dept Human Biol Chem & Genet, Galveston, TX 77550 USA
[5] Armed Forces DNA Identificat Lab, Rockville, MD USA