Genetic determinants of progression of Alzheimer's disease
Transcript of Genetic determinants of progression of Alzheimer's disease
Tuesday, July 16, 2013: Poster Presentations: P3P554
disease in the presence of high genetic risk for disease). These approaches
have not yet been extensively applied in AD research.
P3-011 GENOME-WIDE ASSOCIATION ANALYSES OF
ONSETAGE IN LATE-ONSETALZHEIMER
DISEASE (LOAD) DEMONSTRATE NO STRONG
EFFECT OUTSIDE OF THE APOE REGION
Adam Naj1, Brian Kunkle2, Yo Park3, Gyungah Jun4, Christiane Reitz5,
Ruchita Rajbhandary2, Kara Hamilton-Nelson2, Gary Beecham2,
Eden Martin2, Richard Mayeux5, Jonathan Haines6, Lindsay Farrer4,
Gerard Schellenberg1, Margaret Pericak-Vance2, Alzheimer’s Disease
Genetics Consortium7,1University of Pennsylvania Perelman School of
Medicine, Philadelphia, Pennsylvania, United States; 2University of Miami,
Miami, Florida, United States; 3University of Miami Miller School of
Medicine, Miami, Florida, United States; 4Boston University School of
Medicine, Boston, Massachusetts, United States; 5Columbia University,
New York, New York, United States; 6Vanderbilt University, Nashville,
Tennessee, United States; 7University of Pennsylvania School of Medicine,
Philadelphia, Pennsylvania, United States. Contact e-mail: adamnaj@mail.
med.upenn.edu
Background: LOAD risk loci may also contribute to variation in age of on-
set (AAO) of LOAD, as do the allelic variants in APOE, however roles in
AAO for the other newly identified risk loci (CLU, BIN1, and others)
have not been explored. We examined variants at ten confirmed LOAD
risk loci (APOE, CLU, PICALM, CR1, BIN1, CD2AP, EPHA1, the
MS4A region, ABCA7, and CD33) to determine if they contribute to vari-
ation in AAO among 9,160 LOAD cases in the Alzheimer’s disease Genetics
Consortium (ADGC). Methods: We tested association with AAO for each
locus using linear modeling with covariate adjustment for population sub-
structure and performed a random-effects meta-analysis across datasets.
We also examined genetic burden using genotype scores weighted by risk
effect sizes to examine the aggregate contribution of these loci to variation
in AAO. Results: Analyses confirmed association of APOE regional
variation with AAO (rs6857, P¼3.30310 -96), with statistically significant
associations with AAO (P<0.005) demonstrated at several other LOAD risk
loci, including rs6701713 in CR1 (P ¼0.00717), rs7561528 in BIN1
(P ¼0.00478), rs561655 in PICALM (P ¼0.00223). Associations remained
largely unchanged after additional adjustment for dosage of APOE ε4 al-
leles. Burden analyses showed APOE contributes to 3.1% of variation in
AAO (R 2 ¼0.078) whereas the other nine genes contribute to 1.1% of var-
iation (R 2 ¼0.058) over baseline (R 2 ¼0.047). Secondary analyses of ge-
nome-wide association with AAO among non-risk loci identified several
regions with multiple SNPs demonstrating suggestive associations
(P<10 -6), including one nearing genome-wide statistical significance:
MYO16 (47 SNPs; most significant: rs9521011, P ¼7.62310 -8), CDH20
(4 SNPs; most significant: rs12956834, P ¼6.17310 -6), and SGCZ
(10 SNPs; most significant: rs7016159, P ¼7.70310 -6). Conclusions:
We confirmed the association of APOE variants with AAO among LOAD
cases, and observe associations with AAO in CR1, BIN1, and PICALM.
In contrast to earlier hypothetical modeling, we show that the combined ef-
fects of other loci do not exceed the effect of APOE on AAO, and if addi-
tional genetic contributions to AAO exist, they are likely very small
individually or are hidden in gene-gene interactions.
P3-012 GENETIC DETERMINANTS OF PROGRESSION OF
ALZHEIMER’S DISEASE
Xingbin Wang1, Oscar Lopez1, Robert Sweet2, Michael Barmada1,
Yesim Demirci1, Ilyas Kamboh3, 1University of Pittsburgh, Pittsburgh,
Pennsylvania, United States; 2University of Pittsburgh, Pittsburgh,
Pennsylvania, United States; 3University of Pittsburgh, Pittsburgh,
Pennsylvania, United States. Contact e-mail: [email protected]
Background: Alzheimer’s disease (AD) is characterized by a gradual cog-
nitive and functional decline. Previous studies have shown that the rate of
progression of AD is not uniform, as some patients progress slower than
others, and there are many factors that can affect the slope of progression.
For example, psychotic symptoms can accelerate progression of the disease,
while dementia medication can reduce the rate of decline. However, there
are no studies on the genetic determinants of progression of AD. In the pres-
ent study, we examined the genetic factors associated with the rate of change
at 12 months follow up in a group of patients with AD recruited from a re-
ferral clinic.Methods:We examined the genetic association of 200 SNPs in
ten loci for late-onset AD (APOE, BIN1, CLU, EPHA1, PICALM, CD2AP,
CD33, ABCA7, MS4A4A/MS4A6E, and CR1). Association analysis was
performed using logistic regression model that included age, sex, education,
baseline MMSE score, medication and psychosis.Results:While no signif-
icant association was observed with SNPs in the APOE gene (APOE*4:
P-value¼0.3099; APOE*2: P-value¼0.1935), we found multiple nominal
significant associations (P<0.05) in the CD2AP, BIN1, PICALM and
CD33 genes that harbor both risk and protective SNPs. The most number
of significant SNPs were observed in CD2AP (n¼6; top P-value¼0.00102)
and BIN1 (n¼ 11; top P-value¼ 0.00484).Conclusions: These results indi-
cate that genetic variation in recently identified genes for late-onset ADmay
affect AD progression. Deep resequencing of these genes may enable iden-
tification of causal variants for AD progression.
P3-013 IMAGING GENETICS OF THE SPON1 GENE
VARIANT RS11023139 IN ALZHEIMER’S DISEASE
Kwangsik Nho1, Sungeun Kim1, Shannon Risacher1, Li Shen1,
Richard Sherva2, Robert Green3, Michael Weiner4, Andrew Saykin5,1Indiana University School of Medicine, Indianapolis, Indiana, United
States; 2Boston University, Boston, Massachusetts, United States; 3Brigham
and Women’s Hospital and Harvard Medical School, Boston,
Massachusetts, United States; 4University of California, San Francisco, San
Francisco, California, United States; 5Indiana University School of
Medicine, Indianapolis, Indiana, United States. Contact e-mail: knho@
iupui.edu
Background:Alzheimer’s disease (AD) is a progressive neurodegenerative
condition. Although the genetic effects on rates of cognitive decline and
brain atrophy in AD have received little attention, a recent Genome Wide
Association Study (GWAS) identified rs11023139 in the spondin 1
(SPON1) gene whose minor allele was significantly associated with
a slow rate of cognitive decline. [1] Our aimwas to perform quantitative trait
loci (QTL) association analysis using structural MRI endophenotypes in or-
der to further study the association of the SPON1 gene variant with neuro-
degeneration. Methods: We imputed rs11023139 using MACH and 1000
Genomes Project reference panel in 750 non-Hispanic Caucasian partici-
pants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). The
sample included 185 healthy control (HC) participants and 369 AD. In order
to increase statistical power, the AD group included any subjects diagnosed
with AD as of 3/29/2011 and MCI participants with CSF-positive profile
(Ab1-42 protein <192 pg/mL and 181-phosphorylated-tau protein >23
pg/ml). [2] We used hippocampal grey matter (GM) density and entorhinal
cortex thickness as imaging endophenotypes and performed 1) cross-sec-
tional and 2) longitudinal QTL analysis at baseline and over 2 years, respec-
tively. For the longitudinal QTL analysis, we used imaging endophenotypes
at baseline as a covariate. In addition, we performed voxel-wisewhole-brain
analysis and vertex-wise cortical thickness analysis. Results: SPON1 gene
variant, rs11023139, was significantly associated with hippocampal GM
density at baseline (P ¼0.0173 - 0.0259; uncorrected) and longitudinal
change of the entorhinal cortical thickness (P ¼0.0096 - 0.0292; uncor-
rected) over 2 years in AD only (Table 1,). Furthermore, our whole brain
analysis demonstrated association in multiple brain regions between
rs11023139 and both GM density at baseline (Figure 1,) and decreased
rate of cortical thickness loss over 2 years (Figure 2). Conclusions: Neuro-
imaging genetics suggests that AD patients who are minor allele (A) carriers
of SPON1 gene variant rs11023139 show decreased neurodegeneration.
SPON1 encodes F-spondin protein, which impairs binding of cells to the