[1] Univ Wales Coll Med, Div Psychol Med, Neuropsychiat Genet Unit, Cardiff CF4 4XN, S Glam, Wales
[2] Univ Wales Coll Med, Div Med Genet, Neuropsychiat Genet Unit, Cardiff CF4 4XN, S Glam, Wales
[3] Inst Psychiat, London SE5 8AF, England
[4] Queens Univ Belfast, Dept Geriatr Med, Belfast BT9 7BL, Antrim, North Ireland
[5] Univ Wales Coll Med, Dept Pathol, Cardiff CF4 4XN, S Glam, Wales
[6] Inst Psychiat, MRC, Brain Bank, London SE5 8AF, England
[7] Univ Bristol, Frenchay Hosp, Dept Care Elderly, Bristol BS16 1LE, Avon, England