Barbara Schaffer

Biochemical markers in persons with preclinical familial Alzheimer disease.

Background: Persons at risk for familial Alzheimer disease (FAD) provide a model in which biomarkers can be studied in presymptomatic disease. Methods: Twenty-one subjects at risk for presenilin-1 (n = 17) or amyloid precursor protein (n = 4) mutations underwent evaluation with the Clinical Dementia Rating (CDR) scale. We obtained plasma from all subjects and CSF from 11. Plasma (Aβ40, Aβ42, F2-isoprostanes) and CSF (F2-isoprostanes, t-tau, p-tau181, Aβ40, Aβ42, and Aβ42/Aβ40 ratio) levels were compared between FAD mutation carriers (MCs) and noncarriers (NCs). Results: Plasma Aβ42 levels (25.1 pM vs 15.5 pM, p = 0.031) and the ratio of Aβ42/Aβ40 (0.16 vs 0.11, p = 0.045) were higher in presymptomatic MCs. Among MCs, those with CDR scores of 0.5 had lower plasma Aβ42 levels than those with CDR scores of 0 (14.1 pM vs 25.1, p = 0.02). The ratio of Aβ42 to Aβ40 was also reduced in the CSF (0.08 vs 0.15, p = 0.046) of nondemented MCs compared to NCs. Total CSF tau and p-tau181 levels were elevated in presymptomatic FAD MCs. CSF levels of F2-isoprostanes were also elevated in MCs (n = 7, 48.6 pg/mL) compared to NCs (n = 4, 21.6 pg/mL, p = 0.031). Conclusions: Our data indicate that Aβ42 is elevated in plasma in familial Alzheimer disease (FAD) mutation carriers (MCs) and suggests that this level may decrease with disease progression prior to the development of overt dementia. We also demonstrated that the ratio of Aβ42 to Aβ40 was reduced in the CSF of nondemented MCs and that elevations of t-tau and p-tau181 are sensitive indicators of presymptomatic disease. Our finding of elevated F2-isoprostane levels in the CSF of preclinical FAD MCs suggests that oxidative stress occurs downstream to mismetabolism of amyloid precursor protein.

Association of GSK3B With Alzheimer Disease and Frontotemporal Dementia

BACKGROUND Deposits of abnormally hyperphosphorylated tau are a hallmark of several dementias, including Alzheimer disease (AD), and about 10% of familial frontotemporal dementia (FTD) cases are caused by mutations in the tau gene. As a known tau kinase, GSK3B is a promising candidate gene in the remaining cases of FTD and in AD, for which tau mutations have not been found. OBJECTIVE To examine the promoter of GSK3B and all 12 exons, including the surrounding intronic sequence, in patients with FTD, patients with AD, and aged healthy subjects to identify single-nucleotide polymorphisms associated with disease. DESIGN, SETTING, AND PARTICIPANTS Single-nucleotide polymorphism frequency was examined in a case-control cohort of 48 patients with probable AD, 102 patients with FTD, 38 patients with primary progressive aphasia, and 85 aged healthy subjects. Results were followed up in 2 independent AD family samples consisting of 437 multiplex families with AD (National Institute of Mental Health Genetics Initiative AD Study) or 150 sibships discordant for AD (Consortium on Alzheimers Genetics Study). RESULTS Several rare sequence variants in GSK3B were identified in the case-control study. An intronic polymorphism (IVS2-68G>A) occurred at more than twice the frequency among patients with FTD (10.8%) and patients with AD (14.6%) than in aged healthy subjects (4.1%). The polymorphism showed association with disease in both follow-up samples independently, although only the Consortium on Alzheimers Genetics sample showed the same direction of association as the case-control sample. CONCLUSIONS To our knowledge, this is the first evidence that a gene known to be involved in tau phosphorylation, GSK3B, is associated with risk for primary neurodegenerative dementias. This supports previous work in animal models suggesting that such genes are therapeutic targets.

Gene structure and alternative splicing of glycogen synthase kinase 3 beta (GSK-3β) in neural and non-neural tissues

Glycogen synthase kinase 3 beta (GSK-3beta) is a multifaceted serine-threonine kinase that is of interest both because of its role in the canonical Wnt signaling pathway, which is involved in mammalian brain regionalization, and its role in phosphorylating the microtubule-associated protein Tau. Because of the potential association of GSK-3beta with human developmental and neurodegenerative conditions, we determined its exon/intron boundaries by a combination of sequencing, polymerase chain reaction (PCR) and database mining. Study of GSK-3beta expression using reverse transcription-PCR, Western blotting and Northern blotting showed alternative splicing in nervous and non-nervous system tissues. Both at the protein and mRNA level we were able to identify two isoforms, one full length form containing exon 10 and one without exon 10. At the mRNA level we identified an additional exon that is sometimes seen between exons 8 and 9. Furthermore, rather than the reported 2-3 kb mRNA predominant in non-neural tissues, we identified the major brain isoforms of GSK-3beta as two high molecular weight RNAs (8.4 and 7.7 kb).

Increased prevalence of significant recurrent headache in preclinical familial Alzheimer's disease mutation carriers.

Background/Aims: A previous study found a high prevalence of headaches in persons with familial Alzheimer’s disease (FAD) due to a PSEN1 mutation. In our study we compared the prevalence of headaches between nondemented FAD mutation carriers (MCs) and non-mutation-carrying controls (NCs). Methods: A headache questionnaire that assessed the prevalence of significant headaches and diagnosis of migraine and aura by ICHD-2 criteria was administered to 27 individuals at risk for FAD. Frequency of significant headaches, migraine, and aura were compared between MCs and NCs by χ2 or Fisher’s exact tests. Results: Twenty-three subjects were at risk for PSEN1 mutations and 4 for an APP substitution. The majority of subjects were female (23/27). MCs were more likely to report significant recurrent headache than NCs (67 vs. 25%, p = 0.031). Forty percent of MCs had headaches that met criteria for migraine whereas 17% of NCs met such criteria. The tendency for a higher prevalence of headaches in MCs held for different PSEN1 and APP mutations but was not significant unless all families were combined. Conclusions: In this population, headache was more common in nondemented FAD MCs than NCs. Possible mechanisms for this include cerebral inflammation, aberrant processing of Notch3, or disrupted intracellular calcium regulation.

Behavioral disturbances in early familial Alzheimer's disease

Background: In MMST test the attention, calculation and working memory are being tested by making the patients count from 100 down 7 by 7. Alternatively by testing them to spell the ‘WORLD’ backward. The aim of this study is to compare the two methods for finding the relation of age, sex and education on the total MMST score. Methods: The subjects were chosen among dementia patients coming from 9 centers (TAC-Turquaz Alzheimer Study Group) which had come to be examined for for the first time. Fourhundred fortynine subjects (165 male, 284 female) older than 55 years were analyzed whose MMSE scores are in between 10 to 24. All the participants answered the questions of MMST and the evaluation are made over total score of 30. The subjects were asked to count 100 down 7 by 7 and also to spell the word ‘World’ backwards. Results: The mean MMSE score is 22.2664.76 in spelling the word ‘‘WORLD’’ backwards, the mean MMSE score is 18.964.29 in counting 100 down 7 by 7. We found statisticaly significant set as p1⁄40.0001 between two tests, there is a negative correlation between the age and the test scores (p1⁄40.001, r1⁄40.168) were established, We found also there is no affect of gender on the test scores (p>0.05). Conclusions: While making the clinical diagnosis, standardized alternative tests according to age and education give out more precise information.

Effects of ApoE genotype but not of FAD mutation status in BOLD activation during a novelty encoding task

(4.1.0). VBM (SPM5 and DARTEL) and Freesurfer were used to assess effects within grey matter at each voxel and vertex respectively (FDR corrected, q<0.05). Linear regression was used to assess the individual and independent effects of gender, age and TIV. Results: Age, gender, and TIV were individually associated with all ROI volumes (see table) except age and caudate, age and amygdala and gender and hippocampus. Age and TIV had independent associations with all ROIs. Gender had an independent effect only on whole brain (p<0.001). The 95% CIs of the slope of TIV and ROIs never contained 1 indicating that dividing by TIV is not appropriate head-size adjustment. Age had a widespread negative association with thickness and volume throughout the cortex which survived gender and TIV adjustment (see figure). TIV was associated with increased thickness in the right-sided occipital lobe but not after age and gender adjustment. TIV had a large positive association with grey matter volume, which remained following age and gender adjustment. Gender had some effect on thickness in the left hemisphere (women>men) and a large effect on volume (men>women) but these were lost following TIV and age adjustment. Conclusions: Age has a large effect on results generated by all analysis techniques. Head-size adjustment is unnecessary for thickness analysis should gender and age be used, but is required for volume analyses. Gender-adjustment may be necessary for thickness studies and some ROI analysis but not for VBM should TIV and age be used.

IC-P3-207: Decreased activation in the left medial parietal lobe in presymptomatic FAD mutation carriers in fMRI during an unrelated word pair memory task

2 and Lesion Explorer 3 WMH segmentation was performed, with VichowRobin perivascular spaces excluded. To appreciate the 3-dimensional anatomy of WMH, PV-WMH was defined as any hyperintensity touching the ventricles in 3D, the remaining discrete WMSH were defined as DWWMH. Hypointense components within PV-WMH and DW-WMH of cerebrospinal fluid intensity on T1-based segmentation were considered to represent cystic necrosis. Volumetrics were obtained. Hypointense lesion volumes were expressed as percentage of WMH. Results: Mean percentage of hypointensities were as follows: periventricular (AD 2.2%, NC 0.37%); deep white (AD 2.16%, NC 1.6%), with the PV between group difference approaching significance (p .07). Total PV-WMH and DW-WMH volumes was significantly correlated in NC (r .62, p .019) but not in AD (r .32, p .24). However, DW and PV hypointensities did not show correlation (NC: r -.05, p .87; AD: r .24, p .39). Conclusions: The higher percentage of implied cystic necrosis in the PV distribution, and the differences in DW and PV correlations in AD and NC, suggests a different underlying pathology occurring in the periventricular regions of AD patients. It is recommended that future studies examining WMH should include PV and DW delineations as well as an additional T1-based hypointense segmentation to account for these lesions.

IC-P-090: Elevated hippocampal myo-inositol in subjects with or at-risk for familial AD

temporal lobes. Multidimensional reference spaces were built expressing intensity and local volume change covariances at the voxel level within those two VOIs from reference data. Secondly, study MRIs were projected in this reference space. Classification was achieved by separating groups along one or many of the intensity or local volume change projection coordinates distributions. Results: The 47 patients were separated into 3 distinct groups: 16 decliners ( -1 pt negative change in MMSE), 5 improvers ( 1 pt positive change in MMSE), and 26 stable (MMSE change [-1, 1]). There were no age or MMSE differences between either groups (ANOVA and Tukey-Kramer HSD, P 0.05, DF 2), except baseline MMSE between decliners and improvers (P 0.0003, DF 2). The improvers had the lowest mean baseline MMSE. Results for the classification were based on leave-one-out, forward stepwise linear discriminant analysis (SYSTAT 10.2; P-to-enter 0.05). A classifier built using age, sex and MMSE was 53% accurate at separating the patients (DF 2, Wilk’s 0.69), while the MRI-based classifier was 100% accurate (P-to-enter 0.05, DF 31, Wilk’s 0). Conclusion: This study indicates the possibility of predicting future clinical results on a standardized test using information contained in baseline MRI.

P2-164: Biochemical markers in blood and cerebrospinal fluid of persons with or at-risk for familial AD

John M. Ringman, Greg Cole, Daniel Geschwind, Barbara Schaffer, Yaneth Rodriguez, Jeff Fein, Luis Medina, Domenico Pratico, Steven Younkin, Jeffrey L. Cummings, University of California, Los Angeles, Los Angeles, CA, USA; National Institute of Neurology and Neurosurgery, Mexico City, Mexico; University of Pennsylvania, Pittsburgh, PA, USA; Mayo Clinic, Jacksonville, FL, USA. Contact e-mail: jringman@mednet.ucla.edu