Tamao Tsukie

Mutational analysis in early-onset familial dementia in the Japanese population. The role of PSEN1 and MAPT R406W mutations.

Background: Three major causative genes have been implicated as the cause of early-onset familial Alzheimer’s disease (AD): the amyloid precursor protein gene (APP), presenilin-1 (PSEN1) and PSEN2. Although rare, a tau-related dementia with mutations in the microtubule-associated protein tau gene (MAPT) has been identified in patients showing clinical presentations similar to those of AD. Methods: We performed mutational analysis of APP, PSEN1, PSEN2, and MAPT in 10 Japanese families with early-onset dementia clinically diagnosed as probable Alzheimer’s disease. Results: In 4 index patients, we identified 4 missense PSEN1 mutations, namely, L286V, G378E, L381V, and L392V. The mean age at onset in the patients with PSEN1 mutations was 39 years. In 2 families, we found the R406W mutation in MAPT. The mean age at onset of the patients carrying the R406W mutation was 52 years, and they presented with the peculiar AD-like phenotype without apparent behavioral or language problems. Conclusion: These observations suggest that although PSEN1 mutations are the most frequent cause, the MAPT R406W mutation is an important cause of early-onset familial dementia clinically diagnosed as AD. Differentiation of patients with the MAPT mutation from AD patients by genetic testing would be meaningful, considering that a different therapeutic approach should be applied.

Genes associated with the progression of neurofibrillary tangles in Alzheimer’s disease

The spreading of neurofibrillary tangles (NFTs), intraneuronal aggregates of highly phosphorylated microtubule-associated protein tau, across the human brain is correlated with the cognitive severity of Alzheimer’s disease (AD). To identify genes relevant to NFT expansion defined by the Braak stage, we conducted whole-genome exon array analysis with an exploratory sample set consisting of 213 human post-mortem brain tissue specimens from the entorinal, temporal and frontal cortices of 71 brain-donor subjects: Braak NFT stages 0 (N=13), I–II (N=20), III–IV (N=19) and V–VI (N=19). We identified eight genes, RELN, PTGS2, MYO5C, TRIL, DCHS2, GRB14, NPAS4 and PHYHD1, associated with the Braak stage. The expression levels of three genes, PHYHD1, MYO5C and GRB14, exhibited reproducible association on real-time quantitative PCR analysis. In another sample set, including control subjects (N=30), and in patients with late-onset AD (N=37), dementia with Lewy bodies (N=17) and Parkinson disease (N=36), the expression levels of two genes, PHYHD1 and MYO5C, were obviously associated with late-onset AD. Protein–protein interaction network analysis with a public database revealed that PHYHD1 interacts with MYO5C via POT1, and PHYHD1 directly interacts with amyloid beta-peptide 42. It is thus likely that functional failure of PHYHD1 and MYO5C could lead to AD development.

Evidence for a Common Founder and Clinical Characteristics of Japanese Families with the MAPT R406W Mutation.

Background/Aim: Mutations in MAPT cause frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17). Patients with the MAPT R406W mutation were reported to show phenotypic heterogeneity in different ethnic backgrounds. We here report the clinical and genetic characteristics of Japanese families with the R406W mutation. Methods: We examined the clinical and neuroimaging features of 6 patients from three families with the R406W mutation. We determined the genotypes of intragenic MAPT single-nucleotide polymorphisms (SNPs) and the flanking microsatellite markers to search for a common founder. Results: The initial symptom was memory loss with the average age at onset being 54 years. Anterograde amnesia with episodic memory impairment was the predominant phenotype. Behavioral and personality changes or parkinsonism is not a prominent feature. A brain MRI study revealed marked atrophy of the medial temporal lobe. Genetic analysis of SNPs and microsatellite markers revealed that the affected members of the three families share common genotypes. Conclusion: The findings of the affected members in this study, which corroborate previously reported findings of European families, suggest that the R406W mutation may represent a phenotype of predominant anterograde amnesia in FTLD-17. Our genetic data suggest that a founder effect may account for some families with the R406W mutation.

Cerebrospinal fluid levels of phosphorylated tau and Aβ1-38/Aβ1-40/Aβ1-42 in Alzheimer’s disease with PS1 mutations

Abstract We studied seven cases of Alzheimer’s disease (AD). Six of the patients had presenilin 1 (PS1) mutations (PS1AD). Three novel PS1 mutations (T99A, H131R and L219R) and three other missense mutations (M233L, H163R and V272A) were found in the PS1AD group. We measured the levels of phosphorylated tau (ptau-181, ptau-199) and Aβ (Aβ1-42, Aβ1-40 and Aβ1-38) in the cerebrospinal fluid (CSF) of PS1AD patients, early-onset sporadic AD (EOSAD), late-onset sporadic AD (LOSAD) and non-demented subjects (ND). The CSF levels of Aβ1-42 in the three AD groups were significantly lower than those of the ND group (p < 0.0001). CSF levels of Aβ1-42 in the PS1AD group were significantly lower than those in the two sporadic AD groups. The Aβ1-40 and Aβ1-38 levels in the CSF of the PS1AD group were significantly lower than those of the three other groups (p < 0.0001, respectively). The levels of Aβ1-40, Aβ1-38 and Aβ1-42 in the CSF of the PS1AD group remained lower than those of the ND group for 4 years. Not only CSF Aβ1-42, but also Aβ1-40 and Aβ1-38 decreased in the advanced stages of PS1AD.

A novel presenilin 1 mutation (L282F) in familial Alzheimer’s disease

Sirs, Mutations in the genes of b-amyloid precursor protein (APP), presenilin 1 (PSEN1) and presenilin 2 (PSEN2) have been identified as causative in familial Alzheimer’s disease (FAD) [9]. Mutations in PSEN1 are most common in FAD, and 168 pathogenic PSEN1 mutations have been reported to date [3]. We report a novel mutation of PSEN1 (L282F) in a patient with FAD. A 57-year-old woman consulted our hospital because of progressive memory loss. She had noticed forgetfulness since age 53 and had been treated with donepezil at a local clinic since age 55. She presented with impairment of recent memory and orientation for date and scored 24/30 on the mini-mental state examination without any other neurological deficits. Findings of routine blood tests were normal. Serum apolipoprotein E phenotype was E3/E4. Mild medial temporal atrophy was demonstrated on brain magnetic resonance imaging. Fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) revealed glucose hypometabolism in the bilateral parietal cortices and posterior cingulate gyri. Her family history suggested FAD, but we could not determine the hereditary pattern of FAD (Fig. 1). After written consent was obtained from the patient and her family, all exons of APP, PSEN1 and PSEN2 were analyzed by direct cycle sequencing as described previously [5, 10]. The analysis of PSEN1 demonstrated a C ? T transversion at the first position of codon 282 in exon 8 (genomic accession number: g. 50029C[T), which predicted a L282F substitution (Fig. 2). There were no other mutations detected in the analyzed genes. We also searched for this mutation in 192 Japanese patients with Alzheimer’s disease (AD) or other forms of dementia, and none demonstrated this PSEN1 mutation. We diagnosed this patient as having probable AD according to the NINCDS-ADRDA criteria [6]. The pattern of brain hypometabolism on FDG-PET supported the diagnosis [2, 7]. Although this L282F mutation has not been described previously, two other mutations at the same

Systematic review and meta-analysis of Japanese familial Alzheimer's disease and FTDP-17

Mutations in APP, PSEN1 and PSEN2 as the genetic causes of familial Alzheimer’s disease (FAD) have been found in various ethnic populations. A substantial number of FAD pedigrees with mutations have been reported in the Japanese population; however, it remains unclear whether the genetic and clinical features of FAD in the Japanese population differ from those in other populations. To address this issue, we conducted a systematic review and meta-analysis of Japanese FAD and frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) by literature search. Using this analysis, we identified 39 different PSEN1 mutations in 140 patients, 5 APP mutations in 35 patients and 16 MAPT mutations in 84 patients. There was no PSEN2 mutation among Japanese patients. The age at onset in Japanese FAD patients with PSEN1 mutations was significantly younger than that in patients with APP mutations. Kaplan–Meier analysis revealed that patients with MAPT mutations showed a shorter survival than patients with PSEN1 or APP mutations. Patients with mutations in different genes exhibit characteristic clinical presentations, suggesting that mutations in causative genes may modify the clinical presentations. By collecting and cataloging genetic and clinical information on Japanese FAD and FTDP-17, we developed an original database designated as Japanese Familial Alzheimers Disease Database, which is accessible at http://alzdb.bri.niigata-u.ac.jp/.

NON-ALZHEIMER’S DISEASE SUBJECTS OCCASIONALLY MIMIC CSF PATTERN OF PRECLINICAL ALZHEIMER’S DISEASE

Background:It has been shown that cerebrospinal fluid (CSF) b-amyloid1-42 (Ab1-42) levels show an inverse correlation with brain amyloid plaques, whereas total tau (t-tau) and phosphorylated tau (ptau) levels correlate with the number of neurofibrillary tangles in the brain. Accordingly, reduced CSF Ab1-42 is a useful biomarker for detecting Alzheimer’s disease (AD) subjects even in the preclinical stage. However, reduction of CSFAb1-42 has also been reported in non-AD subjects. To determine a characteristic CSF pattern of non-AD subjects with reduced CSF Ab1-42, we classified subjects with various neurological disorders into four categories based on levels of CSF Ab1-42 and p-tau, then investigated additional CSF biomarkers in each category. Methods: A total of 182 subjects were included in this study. We measured Ab1-42, t-tau, p-tau in CSF using xMap technology, subsequently classified subjects into four categories independently of clinical diagnosis: non-low Ab142/non-high p-tau (n1⁄449), non-low Ab1-42/high p-tau (n1⁄426), low Ab1-42/non-high p-tau (n1⁄458), and low Ab1-42/high p-tau (socalled AD signature, n1⁄449). Next, levels of Ab1-38 and Ab1-40 were measured by MSD, and levels of apoE and Clusterin (apoJ) were measured by ELISA kits. Each biomarker level of four categories was compared, and correlation between each biomarker was analyzed. Results:As expected, more than half subjects categorized as AD signature were clinically diagnosed as AD. Interestingly, a group categorized as low Ab1-42/non-high p-tau included many subjects with progressive supranuclear palsy and idiopathic normal pressure hydrocephalus. Subjects categorized as AD signature showed the reduction of only Ab1-42 level, but not Ab1-38 and Ab1-40. In contrast, in a group categorized as low Ab1-42/non-high p-tau, levels of all Ab species were significantly reduced compared to other groups. Furthermore, this group showed the lowest level of t-tau. Levels of apoE were significantly correlated with all Ab species, whereas levels of Clusterin (apoJ) were correlated well with only Ab1-38 and Ab1-40. Conclusions:There is a group of subjects who show reduced CSFAb1-42 mimicking preclinical AD although they are not expected to have Alzheimer’s pathology in the brain. Their feature is reduced levels of Ab1-38, Ab1-40 and t-tau in CSF.

Longitudinal clinical and neuro-radiological findings in a patient with leukoencephalopathy with brain calcifications and cysts (Labrune syndrome)☆

Since she was 4 years old, the patient had exhibited frequent convulsive seizures, and she experienced severe headaches and depression in adulthood. At the age of 37 years, cerebral calcifications were detected, but she exhibited no cognitive or motor problems. She suffered a cerebral haemorrhage at 49 years old and experienced cognitive dysfunction, dysarthria, dysphagia, and left-hemiparesis as sequelae. After undergoing gastrostomy, she exhibited very slow cognitive deterioration associated with speech disturbance over more than 10 years. She also gradually developed limb spasticity with Babinski signs. Repeated computerised tomography scans revealed unexpected changes including 2 cysts that appeared separately after small haemorrhages, an intracerebral haemorrhage, and intra-cyst bleeding. These longitudinal scans also showed progressive ventricular dilatation and expansion of the leukoencephalopathy, but there were no apparent changes in the intracranial calcifications. Magnetic resonance imaging revealed numerous microbleeds, and magnetic resonance angiography revealed irregularity of the cerebral artery walls with stoppage. Her SNORD118 gene exhibited compound heteromutation of c.38C > G and c.116G > C on different alleles. She was finally diagnosed with leukoencephalopathy with brain calcifications and cysts (Labrune syndrome) at the age of 61 years. Past reports have suggested that diffuse cerebral microangiopathy underlies Labrune syndromes pathogenesis, but we speculate that cerebral macroangiopathy may also underlie it.

TRANSCRIPTOME PROFILE OF PERIPHERAL BLOOD FROM PATIENTS WITH ALZHEIMER'S DISEASE BY RNA-SEQ ANALYSIS

Background:Olfactory deficits have been clearly observed in MCI and AD subjects. Thus, its potential as a biomarker has been proposed and demonstrated by several recent studies. However, further validations of its sensitivity in detecting early AD and specificity in discriminating other neurodegenerative diseases are necessary with concurrent olfactory tests and standardized clinical cognitive examinations. In addition, these findings have not been validated in the Chinese population where aging population is growing rapidly. The goal of this study is to address these critical issues and to evaluate the use of olfactory test battery based on local population in China. Methods: Sixty-one patients with memory complaints from Neurology Clinic of Drum Tower Hospital were recruited into this study. All the participants underwent a battery of neuropsychological tests for cognitive assessment. Thirty-one subjects and seven subjects were diagnosed with MCI and probable AD, respectively. Twenty-one patients were considered as cognitively normal (CN). Olfactory test battery which included one trial of threshold test and two trials of identification tests were performed by OLFACT-C (Osmic Enterprises, Inc., Cincinnati, Ohio, United States). Two patients with nausea of the odors were excluded in this analysis. Results: Increased olfactory threshold (p1⁄40.030) and decreased ability of odor identification (p1⁄40.000) were observed in the MCI and AD patients compared with the CN (Figure 1). Partial correlation analysis showed that odor identification impairment was correlated with age (p1⁄40.001) and cognitive decline (p1⁄40.000). However, augmented olfactory threshold was correlated with age in CN (p1⁄40.011) based on local population in this study. Olfactory threshold was correlated with odor identification (p1⁄40.000) in Spearman correlation analysis, although, as seen also in the Figure 1, the odor threshold data appear to be more variable than odor identification in all three cohorts. Conclusions: In our Chinese cohort, clear olfactory deficits present in both MCI and AD compared to age-matched cognitively normal (CN) subjects. Increased olfactory threshold and decreased ability of odor identification were correlated with aging and cognitive decline. With further validations in follow-up studies of a larger cohort, olfactory test battery could be a viable clinical marker for AD studies.

Gene expression analysis in the postmortem brains classified by Braak NFT-SP staging

cesses. The present study extends an activated EEG medical device for the physiological assessment of brain health looking at multivariate classifiers. Methods: Recent advances in wireless electroencephalography hardware have enabled the development of a novel activated EEG system (MindReader TM) to physiologically focus the assessment of brain health to various sensory circuits and cognitive tasks. The MindReader assesses brain function while actively stimulating the subject with various stimuli. Last year at AAIC Paris, BCI reported univariate results which replicated and extended the published EEG diagnostic literature. This year, multi-variate predictive statistical models were built and tested in JMP Pro v9 from SAS to assess clinical performance to accuracy classify mild AD from Control. Tree based methods (e.g. Random Forests), discriminant analysis (e.g. linear), 2-layer Neural Networks and other techniques were run on our data table of n 1⁄4 10 AD vs n 1⁄4 13 Controls. Results: Several models showed interesting 2, 3, 4 and 5-marker classifiers selected from a list of over 150 published or proprietary EEG biomarker candidates for each of m 1⁄4 16 tasks per subject. Clinical performance ranged from mediocre (60 % sensitivity, 60% specificity) to modest (75% / 72% respectively). Leave one out internal cross-validation was utilized to more accurately characterize the misclassification rate, while the best model will be presented, built on the entire data set. Conclusions: A physiologically focused battery of activated EEG tasks is able to probe elements of brain circuits not presently assessed with standard resting state (Eyes Open or Eyes Closed) quantitative EEG. The MindReader offers a novel alternative to rapidly, portably and non-invasively assess brain health and function. Multi-variate predictive models offer an opportunity to enhance classifier performance, although further work is required to develop the necessary activated EEG signatures to map the brain for its physiological defects.