Identifying Variable Number Tandem Repeats Associated with Alzheimer Disease in Diverse Populations

This goal of this study is to examine the presence of Variable Number Tandem Repeats (VNTRs) in Alzheimer’s disease (AD) population. Within a genome exists short sequences of repeating DNA. While the repeated sequence (usually >6 bases in length) is usually conserved within a population, the number of times the sequence is repeated in any given individual varies. These genetic variants are known as VNTRs and the number of these repeats can be considered a polymorphism, with individuals or families having a different number of repeats than those seen in the general population. In the past VNTRs have been an overlooked polymorphic component of the genome even though a number of VNTRs have been shown to be associated with neurological disorders and brain functions.
We aim to understand not only the presence of specific VNTRs associated with Alzheimer’s disease but also how different phenotypes influences the relationship of these VNTRs to AD, this may inform precise genetic profiles which can be applied to a diverse population. As the associative genetics of AD is known not to be conserved across races it is important to not only assess the dataset as a whole but also the association of the ethno-racial phenotypes to inform these precise genetic profiles. If we can use VNTRs to predict this debilitating disorder it opens up avenues to apply treatments earlier and impact one of the most prevalent social and economic burdens on our society.
Whole genome sequence data will be analyzed using VNTRseek against a set of reference tandem repeats generated from the tandem repeats database. This software determines the presence of a particular repeat. Each output will contain the number of repeats for each VNTR for each genome and this will be filtered for repeats that have a variation from the reference to determine the presence of a VNTR. This will be used to determine allelic frequency of specific polymorphic repeats comparing controls to AD. We will also further separate the analysis into gender and the different ancestral phenotypes in the ADSP to assess for specific alleles that may be more associated in one ethno-racial group than another.

Within a genome exists short sequences of repeating DNA. While the repeated sequence (usually >6 bases in length) is usually conserved within a population, the number of times the sequence is repeated in any given individual varies. These variants are known as Variable Number Tandem Repeats (VNTRs) and the number of these repeats can be considered a polymorphism. In the past VNTRs have been an overlooked polymorphic component of the genome even though a number of VNTRs have been shown to be associated with neurological disorders and brain functions. This study will examine the association of VNTRs in Alzheimer’s disease (AD) population using a specialized program, VNTRseek, to explore the presence of these VNTRs in the whole genome sequences from AD cases and controls. We believe analyzing the distribution of VNTRs in a large and diverse AD population may yield new associative genetic alleles which may not only assist in the prediction of AD development but identify new cellular pathways of interest in understanding the pathophysiology of the disorder.