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Dementia among elderly apolipoprotein E type 4/4 homozygotes: a prospective study
M Ganguli1, J A Cauley, S T DeKosky
1Department of Psychiatry, School of Medicine, Graduate School of Public Health, University of Pittsburgh, Pennsylvania, USA.
Genetic Epidemiology
|January 1, 1995
Summary
The APOE*4 allele is a risk factor for Alzheimer's disease. This study proposes a cost-effective method for dementia research by first identifying individuals with specific phenotypes, then conducting genetic analysis.
Area of Science:
- Genetics
- Neuroscience
- Gerontology
Background:
- The apolipoprotein E (APOE) gene's E*4 allele is an established risk factor for Alzheimer's disease (AD).
- Identifying individuals with rare genetic alleles for AD research is often costly and inefficient.
Purpose of the Study:
- To demonstrate a more cost-effective approach for genetic studies of dementia.
- To investigate the prevalence of dementia in elderly women homozygous for the APOE*4 allele.
Main Methods:
- Phenotyping a cohort of elderly women from an osteoporosis study for dementia.
- Stratifying participants based on dementia phenotype (Clinical Dementia Rating - CDR).
- Restricting genetic evaluation to individuals with specific phenotypes of interest.
Main Results:
- Of 13 women homozygous for APOE*4, 5 showed signs of dementia (CDR 0.5-2).
- All 3 women over 80 years old with the APOE*4 allele were diagnosed with dementia (CDR ≥ 1).
- This 'piggyback' study design efficiently identified dementia cases within a pre-existing cohort.
Conclusions:
- Phenotype-first stratification is a cost-effective strategy for dementia genetic research.
- This approach can accelerate the identification of individuals with specific genetic risk factors like APOE*4.
- Efficiently studying dementia genetics can be achieved by leveraging existing study populations and targeted phenotyping.