Performance on neurocognitive tests by co-twins to dementia cases compared to normal control twins.
Nondemented co-twins of twins who were diagnosed as demented were compared to randomly selected members of normal control twin pairs in which both members of the pair were nondemented. Nondemented co-twins included 23 monozygotic and 62 dizygotic twins; there were 27 normal control twins. Both monozygotic and dizygotic nondemented co-twins of dementia cases scored significantly lower than normal control twins on 5 of 10 cognitive tests. Moreover, monozygotic co-twins of dementia cases had a generally lower score profile than dizygotic co-twins of dementia cases did. These findings show that being at greater genetic risk for dementia is reflected in cognitive performance even in the absence of a diagnosis of dementia.
Gatz
Margaret
M
Department of Psychology, University of Southern California, Los Angeles 90089-1061, USA. gatz@usc.edu
Fiske
Amy
A
Reynolds
Chandra A
CA
Johansson
Boo
B
Fratiglioni
Laura
L
Pedersen
Nancy L
NL
D000368:Aged; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000209:etiology / Q000235:genetics*; D003704:Dementia / Q000235:genetics* / Q000523:psychology*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D012307:Risk Factors; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic