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APOE and APOC1 Promoter Polymorphisms and the Risk of Alzheimer Disease in African American and Caribbean Hispanic Individuals
Benjamin Tycko, MD, PhD;
Joseph H. Lee, PhD;
Alejandra Ciappa, MD;
Anjana Saxena, PhD;
Chi-Ming Li, PhD;
Lin Feng, BA;
Alex Arriaga, BA;
Yaakov Stern, PhD;
Rafael Lantigua, MD;
Neil Shachter, MD;
Richard Mayeux, MD, MSc
Arch Neurol. 2004;61:1434-1439.
Background The APOE 4 allele is a genetic risk factor for Alzheimer disease (AD), though the strength of the association varies by ethnic group. Polymorphisms in regulatory sequences of APOE have also been related to AD, but the effects are inconsistent across studies.
Methods We examined the association between AD and variants in 3 APOE promoters and in the promoter of the adjacent APOC1 gene in African American and Caribbean Hispanic individuals. Polymorphisms tested were the 491A/T, 427T/C, and 219G/T (Th1/E47cs) in the APOE promoter and the HpaI variant in the APOC1 promoter. Using standard research criteria for AD, overall odds ratios were computed and repeated stratified by presence or absence of APOE 4.
Results The APOC1 HpaI+ variant was associated with AD in Caribbean Hispanic individuals, but strong linkage disequilibrium with the APOE 4 allele indicated that this was not an independent effect. No promoter variant in APOE or APOC1 was associated with AD before or after adjusting for age, education, sex, and multiple comparisons. Estimated haplotypes including 219G/T, APOE, and APOC1 differed significantly in Caribbean Hispanic patients and controls but not in African American participants. This effect was primarily owing to the 219G/T-APOE haplotype, but we did not detect significant allele-specific differences in promoter activity comparing reporter constructs containing the APOE 219G and 219 T alleles.
Conclusion These findings exclude a strong or independent influence of APOE or APOC1 promoter polymorphisms on the variation in APOE-related risk of AD in African American and Caribbean Hispanic individuals.
Author Affiliations: Department of Pathology (Drs Tycko, Saxena, and Li and Ms Feng), Division of Neuropathology (Dr Tycko), Taub Institute for Research on Alzheimers Disease and the Aging Brain (Drs Tycko, Ciappa, Stern, Lantigua, and Mayeux), Gertrude H. Sergievsky Center (Drs Lee, Stern, and Mayeux and Mr Arriaga), and the Departments of Neurology (Drs Stern and Mayeux) and Medicine (Drs Lantigua and Shachter), Columbia University College of Physicians and Surgeons, New York, NY.
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