Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s disease

Abstract The common APOE2/E3/E4 polymorphism is determined by two-site haplotypes: C112R and R158C. Due to strong linkage disequilibrium (LD) between the two sites, three of the four expected haplotypes/alleles (E2, E3, E4) have been observed. Compared to the most common E3 haplotype (C112–R158), E4...

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Main Authors: Asma Naseer Cheema, Kang-Hsien Fan, Elizabeth Lawrence, Narges Zafari, Ruyu Shi, Muhammad Muaaz Aslam, Vibha Acharya, Alayna Jean Holderman, Annie Bedison, Eleanor Feingold, M. Ilyas Kamboh
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Language:English
Published: Nature Portfolio 2025-05-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-01263-0
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author Asma Naseer Cheema
Kang-Hsien Fan
Elizabeth Lawrence
Narges Zafari
Ruyu Shi
Muhammad Muaaz Aslam
Vibha Acharya
Alayna Jean Holderman
Annie Bedison
Eleanor Feingold
M. Ilyas Kamboh
author_facet Asma Naseer Cheema
Kang-Hsien Fan
Elizabeth Lawrence
Narges Zafari
Ruyu Shi
Muhammad Muaaz Aslam
Vibha Acharya
Alayna Jean Holderman
Annie Bedison
Eleanor Feingold
M. Ilyas Kamboh
author_sort Asma Naseer Cheema
collection DOAJ
description Abstract The common APOE2/E3/E4 polymorphism is determined by two-site haplotypes: C112R and R158C. Due to strong linkage disequilibrium (LD) between the two sites, three of the four expected haplotypes/alleles (E2, E3, E4) have been observed. Compared to the most common E3 haplotype (C112–R158), E4 (R112–R158) results from a mutation at codon 112, while E2 (C112–C158) results from a mutation at codon 158. The fourth haplotype (E5) having mutations at both sites (R112–C158) has been reported only as an incidental finding in three kindreds. To our knowledge, no systematic search has been done to determine its distribution in the general population. The objective of this study was to search for the elusive haplotype by subcloning a DNA fragment of 177 bp from 355 subjects with the APOE 2/4 genotype followed by sequencing as well as in 11,647 subjects genotyped by TaqMan assays. No example of the E5 haplotype was observed, suggesting it might have a minimum effect, if any, on Alzheimer’s disease risk. Under the assumption of strong LD between the two sites, the estimated probability for the occurrence of the E5 haplotype by recombination event is 3.31E-08, which is similar to 5.58E-08 probability obtained by recurrent point mutation.
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spelling doaj-art-4354a09dbbde4fc4a864efdade48fd092025-08-20T01:51:32ZengNature PortfolioScientific Reports2045-23222025-05-011511810.1038/s41598-025-01263-0Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s diseaseAsma Naseer Cheema0Kang-Hsien Fan1Elizabeth Lawrence2Narges Zafari3Ruyu Shi4Muhammad Muaaz Aslam5Vibha Acharya6Alayna Jean Holderman7Annie Bedison8Eleanor Feingold9M. Ilyas Kamboh10Department of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghDepartment of Human Genetics, School of Public Health, University of PittsburghAbstract The common APOE2/E3/E4 polymorphism is determined by two-site haplotypes: C112R and R158C. Due to strong linkage disequilibrium (LD) between the two sites, three of the four expected haplotypes/alleles (E2, E3, E4) have been observed. Compared to the most common E3 haplotype (C112–R158), E4 (R112–R158) results from a mutation at codon 112, while E2 (C112–C158) results from a mutation at codon 158. The fourth haplotype (E5) having mutations at both sites (R112–C158) has been reported only as an incidental finding in three kindreds. To our knowledge, no systematic search has been done to determine its distribution in the general population. The objective of this study was to search for the elusive haplotype by subcloning a DNA fragment of 177 bp from 355 subjects with the APOE 2/4 genotype followed by sequencing as well as in 11,647 subjects genotyped by TaqMan assays. No example of the E5 haplotype was observed, suggesting it might have a minimum effect, if any, on Alzheimer’s disease risk. Under the assumption of strong LD between the two sites, the estimated probability for the occurrence of the E5 haplotype by recombination event is 3.31E-08, which is similar to 5.58E-08 probability obtained by recurrent point mutation.https://doi.org/10.1038/s41598-025-01263-0APOE haplotypeCloningSequencingGenotypingRecombination, point mutation
spellingShingle Asma Naseer Cheema
Kang-Hsien Fan
Elizabeth Lawrence
Narges Zafari
Ruyu Shi
Muhammad Muaaz Aslam
Vibha Acharya
Alayna Jean Holderman
Annie Bedison
Eleanor Feingold
M. Ilyas Kamboh
Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s disease
Scientific Reports
APOE haplotype
Cloning
Sequencing
Genotyping
Recombination, point mutation
title Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s disease
title_full Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s disease
title_fullStr Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s disease
title_full_unstemmed Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s disease
title_short Search for the elusive haplotype of the APOE polymorphism associated with Alzheimer’s disease
title_sort search for the elusive haplotype of the apoe polymorphism associated with alzheimer s disease
topic APOE haplotype
Cloning
Sequencing
Genotyping
Recombination, point mutation
url https://doi.org/10.1038/s41598-025-01263-0
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