Apolipoproteins E and C1 and brain morphology in memory impaired elders

Previous research has shown that polymorphisms of the apolipoproteins E ( APOE) and APOC1 represent genetic risk factors for dementia and for cognitive impairment in the elderly. The brain mechanisms by which these genetic variations affect behavior or clinical severity are poorly understood. We studied the effect of APOE and APOC1 genes on magnetic resonance imaging measures in a sample of 50 subjects with age-associated memory impairment. The APOE E4 allele was associated with reduced left hippocampal volumes and APOE*E3 status was associated with greater frontal lobe white matter volumes. However, no APOE effects were observed when analyses accounted for other potential confounding variables. The effects of APOC1 on hippocampal volumes appeared to be more robust than those of the APOE polymorphism. However, no modulatory effects on brain morphology outside the medial temporal lobe region were observed when demographic variables, clinical status, and other anatomical brain measurements were taken into consideration. Our results suggest that the role of the APOC1 polymorphism in brain morphology of the cognitively impaired elderly should be examined in further studies.

APOE and APOC1 genetic polymorphisms in age-associated memory impairment

We studied the distribution of two genetic polymorphisms (APOE and APOC1) in a sample of 100 subjects fulfilling the NIMH criteria for age-associated memory impairment (AAMI) and 124 controls. We found significant associations both for APOE and APOC1 loci and their combinations with the AAMI condition. The findings in our sample suggest that memory-impaired subjects as described by the NIMH may be genetically differentiated from normally aging subjects in relation to these two polymorphisms and indicate the interest of considering variations in the APOC1 gene for further studies in cognitive aging.

Angiotensin I converting enzyme polymorphism in humans with age-associated memory impairment: relationship with cognitive performance

We compared the distribution of an insertion (I)/deletion (D) polymorphism coding for the angiotensin I converting enzyme (ACE) gene in 100 subjects fulfilling NIMH criteria for Age-associated memory impairment (AAMI) and 124 controls. We found significantly reduced prevalences of the ACE I/I genotype together with increases of the ACE D allele in the AAMI group. We further compared the neuropsychological performance of the AAMI group according to their ACE genotype. Those AAMI subjects presenting the ACE I/I genotype exhibited better performance on a measure of frontal lobe function. Our results suggest that the lack of the ACE I/I genotype and the presence of the ACE D allele are associated with memory impairment in the elderly.