1. Genetic Screening for Alzheimer’s Disease Thorstensen: Genetic Screening for Alzheimer's Disease 1

2. Agenda  What is Alzheimer’s Disease (AD)?  Genes associated with AD  The APOE gene Thorstensen: Genetic Screening for Alzheimer's Disease 2

3. What is Alzheimer’s Disease (AD)?  Type of dementia that causes problems with memory, thinking and behavior  Most common form of dementia  Not a normal part of aging  Worsens over time  Has no current cure, but treatments for symptoms are available and research continues Thorstensen: Genetic Screening for Alzheimer's Disease 3

4. AD changes the whole brain Thorstensen: Genetic Screening for Alzheimer's Disease 4

5. The prime suspects for the cause of cell death and tissue loss are plaques and tangles Thorstensen: Genetic Screening for Alzheimer's Disease 5

6. Genes associated with AD  Four leading genes determined to be causative elements: APP, PS1, PS2 and APOE  Mutations in APP, PS1 and PS2 cause early onset AD (younger than 65 years)  APOE is a risk factor for late onset AD (older than 65 years) Thorstensen: Genetic Screening for Alzheimer's Disease 6

7. The APOE gene  Present in 30-50% of late onset AD patients  Apolipoprotein E  Secretory protein  Synthesized in the liver  Proposed function:  Amyloid β aggregation and clearance  Intracellular signaling through low-density lipoprotein receptor- related protein (LRP) Thorstensen: Genetic Screening for Alzheimer's Disease 7

8. Screening and Evaluation of Deleterious SNPs in the APOE Gene of AD  SNP = Single-Nucleotide Polymorphism  nsSNP = nonsynonymous SNP  Several SNPs present in the APOE gene that serve as biomarkers in exploring the genetic basis of AD  Research Goal: Identify deleterious nsSNPs associated with the APOE gene Thorstensen: Genetic Screening for Alzheimer's Disease 8

9. Why use SNPs, specifically nsSNPs?  SNPs are the most common polymorphisms of DNA sequence variation for mapping complex genetic traits  500,000 SNPs in coding regions of human genome  Several databases of SNPs  nsSNPs cause changes in amino acid residues  These mutations are most likely to cause structural changes therefore altering the function of a protein (like APOE  plaques and tangles) Thorstensen: Genetic Screening for Alzheimer's Disease 9

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11. Used the Function Analysis and Selection Tool for Single Nucleotide Polymorphisms (FASTSNP) server to detect 7 nsSNPs with high possible functional effects Risk score of 3-4: highly polymorphic Thorstensen: Genetic Screening for Alzheimer's Disease 11

12. Used the Swiss Protein Data Bank (PDB) viewer to predict mutations in the APOE gene and the Normal Mode Analysis, Deformation, and Refinement (NOMAD-Ref) server to detect 3 mutant- structures with higher total energies and RMSD values compared to the homology modeled structure Deviation in structure implies a functional change Thorstensen: Genetic Screening for Alzheimer's Disease 12

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14. Must test predicted impact of these nsSNPs using animal models or cell lines to determine if the functionally of the protein has indeed been altered AD has a complex genetic background as well as environmental factors, making research for a cure challenging Thorstensen: Genetic Screening for Alzheimer's Disease 14