- Email: [email protected]
P4-064 Fine mapping of an AD candidate region on chromosome 9
Poster Session P4: Genetic Factors of Alzheimer's Disease ~
A L L E L E I C V A R I A T I O N AT T H E A218C
TRYPTOPHAN HYDROXYLASE POLYMORPHISM INFLUENCES A G I T A T I O N A N D A G G R E S S I O N 1N ALZHEIMER'S D I S E A S E David Craig*, Dominic J. Hart, Robin Carson, Stephen P. McIlroy, Peter Passmore. Queen's University, Belfast, United Kingdom. Contact
e-mail: [email protected] Background: The behavioural and psychological symptoms of dementia (BPSD) are common, distressing to carers, and directly linked to the requirement for institutional care. Symptoms of aggression and agitation are particularly difficult for carers to tolerate. The origin of these features is unclear although genetic and environmental modification of pre-frontal serotonergic circuitry which regulates the control of negative emotions is proposed. Objective(s): Following the suggestion that the A218C intronic polymorphism of the tryptophan hydroxylase gene influences aggression and anger in non-demented individuals we tested the influence of A2!8C on symptoms of agitation/aggression in Alzheimer's disease. Methods: Three hundred and ninety six patients were phenotyped for aggression/agitation using the Neuropsychiatric Inventory and cross-tabulated against the A218C polymorphism. Results: Overall, 50% of participants experienced agitation/aggression in the month prior to interview. It was observed that male patients with a history of agitation/aggression were significantly more likely to possess C-containing genotypes (X 2 = 6.035, df = 2, p = 0.049). Conclusions: Aggression in male subjects with Alzheimer's disease is genetically linked to potymorphic variation at the tryptophan hydroxylase gene.
~
VERY EARLY ONSET FAMILIAL ALZHEIMER'S D I S E A S E WITH LEWY BODIES WITHOUT KNOWN CAUSATIVE MUTATIONS
B.J. Snider* t, Craig E. Hou i , Rarniro Jervis 2, Corinne L. Lendon 3, JoAnne Norton 1, Alison M. Goate 1, Dan W. McKeel Jr. I, John C. Morris 1.1 Washington University School of Medicine, St Louis, MO,
$491
ease, FAD). Mutations, most commonly in the presenilin 1 (PSEN1) gene, are found in slightly more than half of early onset FAD families. Objective: We analyzed the clinical, neuropathological and genetic features of a family with very early onset FAD. Methods: The proband underwent full clinical assessment. Family history was obtained through interviews with collateral sources and review of medical records. Post-mortem examination was obtained in the proband; limited pathological samples and autopsy records of 2 affected family members were available. The proband was screened for genetic mutations in the coding regions of the PSEN1 and PSEN2 genes, and in exons 16 and 17 of the amyloid precursor protein gene. Results: A father and his son and daughter (the proband) developed dementia at a mean age of 27 years (range 26-27 years). All three had similar clinical features including myoclonus, seizures, and rigidity. All three were confirmed to have AD by neuropathology. Alpha-synuclein staining of the proband demonstrated sufficient Lewy body (LB) pathology in brainstem, limbic areas and neocortex to fulfill McKeith 1996 consensus criteria for Dementia with Lewy Bodies. No mutations were found in the coding regions of the PSEN1 and PSEN2 genes or in exons 16 and 17 of the APP gene. The proband was homozygous for the E3 allele of apolipoprotein E. Conclusions: Mutations in PSEN1 result in a clinical phenotype characterized by early onset dementia myoclonus, seizures, and rigidity. This very early onset FAD kindred demonstrated a very similar clinical phenotype. No mutations were present in any of the genes known to be associated with FAD, suggesting that additional unknown causative genes can present with a phenotype resembling that of PSEN1 mutations. To our knowledge, this kindred has the earliest reported onset of pathologically confirmed AD with widespread Lewy Body pathology; the relative contribution of the two pathologies to the clinical phenotype is unknown.
•fO6-•
FINE M A P P I N G O F AN AD CAN DIDATE R E G I O N
ON CHROMOSOME 9
Howard Wiener *t , Rodney Go I , Rodney Perry 1, Deborah Blacker 2, Susan Bassett 3. 1 University of Alabama at Birmingham, Birmingham, AL,
USA; 2Mount Sinai School of Medicine, New York, NY, USA; SThe University of Birmingham, Birmingham, United Kingdom. Contact e-mail: sniderj @neuro, wustl.edu Background: Early onset Alzheimer's disease (EOAD) accounts for less than 10% of all cases of Alzheimer's disease (AD). However, EOAD is important for understanding AD mechanisms. A subset of EOAD cases occurs with an autosomal dominant inheritance pattern (familial Alzheimer's dis-
USA; 2MGH, Boston, MA, USA; 3Johns Hopkins University, Baltimore, MD, USA. Contact e-mail: [email protected] Background: A recent 9cM full genome scan of LOAD in families ascertained by the NIMH Alzheimer's Disease Genetics Initiative indicated suggestive linkage to a region on chromosome 9 (9q22). This peak was enhanced when attention was limited to pedigrees with all affected individuals having onset after age 65. Objective(s): Verify the linkage results from the genome scan, and increase precision of the estimate of the
Figure 1. Comparison of ZIr Scores tor Original and Updated Marker Sets Using Late Onset Families 4.5. 4.0
3.5 3.8 2.5 2.0 1.5 1.0
/J
\,
./'----
0.5 0.0 20
40
60 Updated
•
80 Updated Significant
100 Original
Abstract P4-064 - Fig. l.
120 °
140
Original Signit]carl/
160
180
Poster Session P4: Genetic Factors of Alzheimer's Disease
$492
Figure 2. Comparison of SlBPAL Results with Original and Updated Marker Sets Using the Late Onset Families, Corrected for ApoE and Educatien 0.12
0.1
0,08
0.06
0.04
O,O2
0
/ -0.02 20
60
40
Original
,
80
100
OriginaISignillcant
120
Updated •
140
160
180
UpdatedBignil~ca~
Abstract P4-064 - Fig. 2. position of the putative associated gene. Methods: As a first step in fine mapping this region, we identified five microsatellites in the region of the linkage peak: D9S152, D9S252, D9S1815, D9S1801, and D9S51. These were genotyped using the CEQ 8000, a capillary electrophoresis system from Beckman. Linkage was investigated with both Genehunter Plus, which generates both Zlr scores and HLOD (Heterogeneity LOD) scores, and the SAGE V 4.5 program SIBPAL, which performs Haseman-Elston regression, allowing for additional covariates. The covariates used here were genotype at the ApoE locus, and education. The FBAT (Family Based Association Test) program was used to ascertain evidence for association between the alleles of these loci and the occurrence of LOAD. Results: Strong evidence for linkage with this region of chromosome 9 persisted in this analysis. Compared to the original genome scan, the Zlr value at the peak for the late onset subset increased from 3.3 to slightly over 4.0 (Fig. 1). The maximum HLOD exceeded 4.9. Haseman-Elston analysis of this region similarly showed strong evidence of linkage with this region (Fig. 2). The peak of this region was closest to the marker D9S1815. One allele of marker D9S252 showed very strong evidence of association with LOAD, but lower evidence of linkage. Conclusions: An assumption of standard linkage analyses is linkage equilibrium between marker and trait locus, which may account for the lower evidence of linkage near marker D9S252. The regions around both this marker and around marker D9S1815, are definite fine mapping and candidate gene targets. Both of these regions will be followed up with SNPs spaced about 1 cM apart and candidate genes.
•
GLU298ASP P O L Y M O R P H I S M OF T H E E-NOS G E N E AND H O M O C Y S T E I N E L E V E L S IN PATIENTS W I T H A L Z H E I M E R ' S DISEASE AND VASCULAR DEMENTIA
Daniela Galimberti* 1, Ilaria Guidil, Eliana Venturelfi 1 Alberto Gatti 1, Chiara Fenoglio 1, Roberto Del Bo 1, Carlo Lovati 2, Sara Galbiatil, Giacomo P. Comi 1, Clandio Mariani 2, Gianluigi Forloni 3, Pierluigi Baron 1, Giancarlo Conti 1, Nereo Bresolin 1, Elio Scarpinil. I IRCCS Ospedale Maggiore, University of Milan, Centro Dino Ferrari, Milan, Italy; e Ospedale L. Sacco, University of Milan, Milan, Italy; 3Istituto "3,1.Negri", Milan, Italy. Contact e-maih daniela, g alimberti @unimi, it
Background: Elevated total plasma homocysteine (tHey) levels have been demonstrated to be a risk factor for vascular dementia (VaD) and Alzbeimer's disease (AD). Besides, several genetic polymorphisms have been proposed as susceptibility factors, including the genotype Glu/Glu of the polymor-
phism Glu298Asp in eNOS gene. Moreover, further studies suggest that this polymorphism seems to have no effect on plasma levels of homocysteine, folate and lipids, and on vascular endothefial function in healthy subjects. Objective(s): 1) To determine the distribution of the Glu298Asp polymorphism and of the ApoE genotype in a population of Italian patients with AD compared with age-matched controls. 2) To detemine tHcy levels in AD and VaD patients and correlate them with e-NOS and ApoE genotype. Methods: The distribution of the Glu298Asp polymorphism as well as ApoE genotype was determined in a population of 362 Italian patients with AD as well as in 236 age-matched controls. Genomic DNA was isolated from blood and polymorphisms were determined by PCR-RFLP assay, tHcy levels were evaluated in 84 out of 362 AD patients as well as in 23 VaD patients. Results: The frequency of the Glu298Asp in both our AD and control populations was similar to the one reported for Caucasians. No differences in the distribution of the polymorphism between AD and controls were shown, even stratifying for the presence of e4 allele, tHcy levels in AD patients homozygous for the mutation were lower compared with wild type or heterozygous. The same trend was observed in VaD patients. Conclusions: The Glu298Asp polymorphism seems not to be associated with AD, both by itself or in combination with the ~4 allele. However, the presence of two mutated alleles may contribute to lower the levels of tHcy, thus decreasing the negative effects due to hyperhomocysteinaemia.
•
INDEPENDENT C A S E - C O N T R O L C O N F I R M A T I O N OF ASSOCIATION O F DLD W I T H AD
Abraham M. Brown* 1,2, Fahienne S. Wavrant-De Vrieze 3, Derek Gordon 4, Hsinhwa Lee 2, John Hardy 3 , John Blass 1,2.1 Weill Cornell Medical College, New York, NY, USA; 2Burke Medical Research Institute, White Plains, NY, USA; 3Lab. Neurogenetics, Bethesda, MD, USA; 4Rockefeller University, New York, NY, USA. Contact e-mail: ambrown @med.co rnell, edu
Background: Abundant biochemical evidence links deficient activities of the mitochondrial a-ketoghitarate and pyruvate dehydrogenase complexes with neuropathological Alzheimer's disease (AD). These complexes share a common gene product, DLD, which falls within a Chr. 7 region that is in linkage disequilibrium with AD. Earlier genotyping studies of predominantly Ashkenazi Jewish Caucasians revealed association between a complex diplotype composed of four SNPs and AD, independent of ApoE status. In that study, the association with the DLD genotypes was restricted to the male population in both the Caucasian series (p = 0.0009, n = 83) and the Ashkenazi Jewish subseries (p = 0.017, n = 49) [Brown etal, Am J
A L L E L E I C V A R I A T I O N AT T H E A218C
TRYPTOPHAN HYDROXYLASE POLYMORPHISM INFLUENCES A G I T A T I O N A N D A G G R E S S I O N 1N ALZHEIMER'S D I S E A S E David Craig*, Dominic J. Hart, Robin Carson, Stephen P. McIlroy, Peter Passmore. Queen's University, Belfast, United Kingdom. Contact
e-mail: [email protected] Background: The behavioural and psychological symptoms of dementia (BPSD) are common, distressing to carers, and directly linked to the requirement for institutional care. Symptoms of aggression and agitation are particularly difficult for carers to tolerate. The origin of these features is unclear although genetic and environmental modification of pre-frontal serotonergic circuitry which regulates the control of negative emotions is proposed. Objective(s): Following the suggestion that the A218C intronic polymorphism of the tryptophan hydroxylase gene influences aggression and anger in non-demented individuals we tested the influence of A2!8C on symptoms of agitation/aggression in Alzheimer's disease. Methods: Three hundred and ninety six patients were phenotyped for aggression/agitation using the Neuropsychiatric Inventory and cross-tabulated against the A218C polymorphism. Results: Overall, 50% of participants experienced agitation/aggression in the month prior to interview. It was observed that male patients with a history of agitation/aggression were significantly more likely to possess C-containing genotypes (X 2 = 6.035, df = 2, p = 0.049). Conclusions: Aggression in male subjects with Alzheimer's disease is genetically linked to potymorphic variation at the tryptophan hydroxylase gene.
~
VERY EARLY ONSET FAMILIAL ALZHEIMER'S D I S E A S E WITH LEWY BODIES WITHOUT KNOWN CAUSATIVE MUTATIONS
B.J. Snider* t, Craig E. Hou i , Rarniro Jervis 2, Corinne L. Lendon 3, JoAnne Norton 1, Alison M. Goate 1, Dan W. McKeel Jr. I, John C. Morris 1.1 Washington University School of Medicine, St Louis, MO,
$491
ease, FAD). Mutations, most commonly in the presenilin 1 (PSEN1) gene, are found in slightly more than half of early onset FAD families. Objective: We analyzed the clinical, neuropathological and genetic features of a family with very early onset FAD. Methods: The proband underwent full clinical assessment. Family history was obtained through interviews with collateral sources and review of medical records. Post-mortem examination was obtained in the proband; limited pathological samples and autopsy records of 2 affected family members were available. The proband was screened for genetic mutations in the coding regions of the PSEN1 and PSEN2 genes, and in exons 16 and 17 of the amyloid precursor protein gene. Results: A father and his son and daughter (the proband) developed dementia at a mean age of 27 years (range 26-27 years). All three had similar clinical features including myoclonus, seizures, and rigidity. All three were confirmed to have AD by neuropathology. Alpha-synuclein staining of the proband demonstrated sufficient Lewy body (LB) pathology in brainstem, limbic areas and neocortex to fulfill McKeith 1996 consensus criteria for Dementia with Lewy Bodies. No mutations were found in the coding regions of the PSEN1 and PSEN2 genes or in exons 16 and 17 of the APP gene. The proband was homozygous for the E3 allele of apolipoprotein E. Conclusions: Mutations in PSEN1 result in a clinical phenotype characterized by early onset dementia myoclonus, seizures, and rigidity. This very early onset FAD kindred demonstrated a very similar clinical phenotype. No mutations were present in any of the genes known to be associated with FAD, suggesting that additional unknown causative genes can present with a phenotype resembling that of PSEN1 mutations. To our knowledge, this kindred has the earliest reported onset of pathologically confirmed AD with widespread Lewy Body pathology; the relative contribution of the two pathologies to the clinical phenotype is unknown.
•fO6-•
FINE M A P P I N G O F AN AD CAN DIDATE R E G I O N
ON CHROMOSOME 9
Howard Wiener *t , Rodney Go I , Rodney Perry 1, Deborah Blacker 2, Susan Bassett 3. 1 University of Alabama at Birmingham, Birmingham, AL,
USA; 2Mount Sinai School of Medicine, New York, NY, USA; SThe University of Birmingham, Birmingham, United Kingdom. Contact e-mail: sniderj @neuro, wustl.edu Background: Early onset Alzheimer's disease (EOAD) accounts for less than 10% of all cases of Alzheimer's disease (AD). However, EOAD is important for understanding AD mechanisms. A subset of EOAD cases occurs with an autosomal dominant inheritance pattern (familial Alzheimer's dis-
USA; 2MGH, Boston, MA, USA; 3Johns Hopkins University, Baltimore, MD, USA. Contact e-mail: [email protected] Background: A recent 9cM full genome scan of LOAD in families ascertained by the NIMH Alzheimer's Disease Genetics Initiative indicated suggestive linkage to a region on chromosome 9 (9q22). This peak was enhanced when attention was limited to pedigrees with all affected individuals having onset after age 65. Objective(s): Verify the linkage results from the genome scan, and increase precision of the estimate of the
Figure 1. Comparison of ZIr Scores tor Original and Updated Marker Sets Using Late Onset Families 4.5. 4.0
3.5 3.8 2.5 2.0 1.5 1.0
/J
\,
./'----
0.5 0.0 20
40
60 Updated
•
80 Updated Significant
100 Original
Abstract P4-064 - Fig. l.
120 °
140
Original Signit]carl/
160
180
Poster Session P4: Genetic Factors of Alzheimer's Disease
$492
Figure 2. Comparison of SlBPAL Results with Original and Updated Marker Sets Using the Late Onset Families, Corrected for ApoE and Educatien 0.12
0.1
0,08
0.06
0.04
O,O2
0
/ -0.02 20
60
40
Original
,
80
100
OriginaISignillcant
120
Updated •
140
160
180
UpdatedBignil~ca~
Abstract P4-064 - Fig. 2. position of the putative associated gene. Methods: As a first step in fine mapping this region, we identified five microsatellites in the region of the linkage peak: D9S152, D9S252, D9S1815, D9S1801, and D9S51. These were genotyped using the CEQ 8000, a capillary electrophoresis system from Beckman. Linkage was investigated with both Genehunter Plus, which generates both Zlr scores and HLOD (Heterogeneity LOD) scores, and the SAGE V 4.5 program SIBPAL, which performs Haseman-Elston regression, allowing for additional covariates. The covariates used here were genotype at the ApoE locus, and education. The FBAT (Family Based Association Test) program was used to ascertain evidence for association between the alleles of these loci and the occurrence of LOAD. Results: Strong evidence for linkage with this region of chromosome 9 persisted in this analysis. Compared to the original genome scan, the Zlr value at the peak for the late onset subset increased from 3.3 to slightly over 4.0 (Fig. 1). The maximum HLOD exceeded 4.9. Haseman-Elston analysis of this region similarly showed strong evidence of linkage with this region (Fig. 2). The peak of this region was closest to the marker D9S1815. One allele of marker D9S252 showed very strong evidence of association with LOAD, but lower evidence of linkage. Conclusions: An assumption of standard linkage analyses is linkage equilibrium between marker and trait locus, which may account for the lower evidence of linkage near marker D9S252. The regions around both this marker and around marker D9S1815, are definite fine mapping and candidate gene targets. Both of these regions will be followed up with SNPs spaced about 1 cM apart and candidate genes.
•
GLU298ASP P O L Y M O R P H I S M OF T H E E-NOS G E N E AND H O M O C Y S T E I N E L E V E L S IN PATIENTS W I T H A L Z H E I M E R ' S DISEASE AND VASCULAR DEMENTIA
Daniela Galimberti* 1, Ilaria Guidil, Eliana Venturelfi 1 Alberto Gatti 1, Chiara Fenoglio 1, Roberto Del Bo 1, Carlo Lovati 2, Sara Galbiatil, Giacomo P. Comi 1, Clandio Mariani 2, Gianluigi Forloni 3, Pierluigi Baron 1, Giancarlo Conti 1, Nereo Bresolin 1, Elio Scarpinil. I IRCCS Ospedale Maggiore, University of Milan, Centro Dino Ferrari, Milan, Italy; e Ospedale L. Sacco, University of Milan, Milan, Italy; 3Istituto "3,1.Negri", Milan, Italy. Contact e-maih daniela, g alimberti @unimi, it
Background: Elevated total plasma homocysteine (tHey) levels have been demonstrated to be a risk factor for vascular dementia (VaD) and Alzbeimer's disease (AD). Besides, several genetic polymorphisms have been proposed as susceptibility factors, including the genotype Glu/Glu of the polymor-
phism Glu298Asp in eNOS gene. Moreover, further studies suggest that this polymorphism seems to have no effect on plasma levels of homocysteine, folate and lipids, and on vascular endothefial function in healthy subjects. Objective(s): 1) To determine the distribution of the Glu298Asp polymorphism and of the ApoE genotype in a population of Italian patients with AD compared with age-matched controls. 2) To detemine tHcy levels in AD and VaD patients and correlate them with e-NOS and ApoE genotype. Methods: The distribution of the Glu298Asp polymorphism as well as ApoE genotype was determined in a population of 362 Italian patients with AD as well as in 236 age-matched controls. Genomic DNA was isolated from blood and polymorphisms were determined by PCR-RFLP assay, tHcy levels were evaluated in 84 out of 362 AD patients as well as in 23 VaD patients. Results: The frequency of the Glu298Asp in both our AD and control populations was similar to the one reported for Caucasians. No differences in the distribution of the polymorphism between AD and controls were shown, even stratifying for the presence of e4 allele, tHcy levels in AD patients homozygous for the mutation were lower compared with wild type or heterozygous. The same trend was observed in VaD patients. Conclusions: The Glu298Asp polymorphism seems not to be associated with AD, both by itself or in combination with the ~4 allele. However, the presence of two mutated alleles may contribute to lower the levels of tHcy, thus decreasing the negative effects due to hyperhomocysteinaemia.
•
INDEPENDENT C A S E - C O N T R O L C O N F I R M A T I O N OF ASSOCIATION O F DLD W I T H AD
Abraham M. Brown* 1,2, Fahienne S. Wavrant-De Vrieze 3, Derek Gordon 4, Hsinhwa Lee 2, John Hardy 3 , John Blass 1,2.1 Weill Cornell Medical College, New York, NY, USA; 2Burke Medical Research Institute, White Plains, NY, USA; 3Lab. Neurogenetics, Bethesda, MD, USA; 4Rockefeller University, New York, NY, USA. Contact e-mail: ambrown @med.co rnell, edu
Background: Abundant biochemical evidence links deficient activities of the mitochondrial a-ketoghitarate and pyruvate dehydrogenase complexes with neuropathological Alzheimer's disease (AD). These complexes share a common gene product, DLD, which falls within a Chr. 7 region that is in linkage disequilibrium with AD. Earlier genotyping studies of predominantly Ashkenazi Jewish Caucasians revealed association between a complex diplotype composed of four SNPs and AD, independent of ApoE status. In that study, the association with the DLD genotypes was restricted to the male population in both the Caucasian series (p = 0.0009, n = 83) and the Ashkenazi Jewish subseries (p = 0.017, n = 49) [Brown etal, Am J