Katsuya Urakami

Large-scale, multicenter study of cerebrospinal fluid tau protein phosphorylated at serine 199 for the antemortem diagnosis of Alzheimer's disease

We surveyed a total of 570 cerebrospinal fluid (CSF) samples from a variety of diseases, including Alzheimers disease (AD; n = 236), non‐AD‐demented and nondemented diseases (n = 239), and normal controls (n = 95) to quantitate levels of tau protein phosphorylated at serine 199 (CSF/phospho‐tau199) by a recently established sandwich ELISA. The CSF/phospho‐tau199 levels in the AD group were significantly elevated compared to those in all the other non‐AD groups. Receiver operating characteristics curves showed that the diagnostic sensitivity and specificity for the AD group versus all the other non‐AD groups using the CSF/phospho‐tau199 were 85.2% and 85.0%, respectively. Furthermore, there was a significant positive correlation between CSF/phospho‐tau199 and CSF/total‐tau levels in the AD group. Elevated CSF/phospho‐tau199 in the AD group was noted irrespective of age, gender, dementia severity, and number of apolipoprotein E4 alleles. Thus, we suggest that CSF/phospho‐tau199 may be a novel and logical biomarker in supporting antemortem diagnosis of AD.

The homozygous C677T mutation in the methylenetetrahydrofolate reductase gene is a genetic risk factor for migraine

Increased homocysteine levels are associated with various pathological conditions in humans, including stroke and cardiovascular disorders. Homocysteine acts as an excitatory amino acid in vivo and may influence the threshold of migraine headache. Frosst et al. [1995] reported an association between the homozygous C677T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and serum homocysteine levels. This study was designed to determine the prevalence of the MTHFR mutation in Japanese patients with migraine and tension-type headache (TH). Seventy-four patients with migraine headaches (22 with aura and 52 without aura), 47 with THs, and 261 normal controls were recruited. Genotyping of MTHFR C677T polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism. We detected that the incidence of the homozygous transition (T/T) in migraine sufferers (20.3%) was significantly higher than that in controls (9.6%). Moreover, the frequency of the T/T genotype in individuals with migraine headaches with aura was remarkably high (40.9%). The MTHFR T allele was more frequent in the migraine group than in the control group. Our results support the conclusion that the MTHFR gene, causing mild hyperhomocysteinemia may be a genetic risk factor for migraine. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:762-764, 2000.

Phosphorylated tau in human cerebrospinal fluid is a diagnostic marker for Alzheimer's disease.

Microtubule-associated protein tau in cerebrospinal fluid (CSF) has been proposed as a diagnostic marker for Alzheimers disease (AD), but there is overlap between AD patients and non-AD controls. To improve the diagnostic accuracy, we measured phosphorylated tau in CSF, because phosphorylated tau accumulates as pathological paired helical filaments in neurons of the AD brain. Immunoblot showed that CSF contained a 32 kDa N-terminal fragment of tau that was partially phosphorylated on Ser199, Thr231 and Ser235. A sandwich enzyme immunoassay revealed that phosphorylated CSF-tau levels were significantly higher in AD patients than those in non-AD controls. Discrimination between the two groups was clearer in phosphorylated CSF-tau than in total CSF-tau. The data indicate that elevated phosphorylated CSF-tau level is a more specific diagnostic marker for AD.

Population-based door-to-door survey of migraine in Japan: The Daisen Study

Objectives.—To determine prevalence and characteristics of migraine in Japan, and to investigate use of medical care and whether food preference is associated with risk of migraine.

Novel amyloid precursor protein gene missense mutation (D678N) in probable familial Alzheimer’s disease

Objective: To describe a novel missense mutation, Asp678Asn (D678N), in the amyloid precursor protein (APP) gene in a Japanese pedigree of probable familial Alzheimer’s disease (FAD). Subject: The proband was a women of 72. Symptoms of dementia that fulfilled the criteria for probable Alzheimer’s disease appeared at about 60 years of age, and slowly worsened over more than 10 years without evident cerebrovascular complications, either clinically or neuroradiologically. Methods: Polymerase chain reaction single strand conformational polymorphism (PCR-SSCP) analysis followed by sequence analysis was used to examine genomic DNA of the proband for mutations in the APP gene exons 16 and 17. Results: Analysis of the APP exon 16 in the proband showed a GAC to AAC nucleotide substitution in codon 678 of the APP gene, causing an amino acid substitution of Asp to Asn (D678N). Heterozygosity of the APP D678N mutation was found in the proband and in the demented elder sister. Conclusions: The production and accumulation of mutated Abeta (Asn7-Abeta) or the misfunction of D678N mutant APP may have pathogenic properties for the development of Alzheimer’s disease in this pedigree.

SORL1 Is Genetically Associated with Late-Onset Alzheimer’s Disease in Japanese, Koreans and Caucasians

To discover susceptibility genes of late-onset Alzheimer’s disease (LOAD), we conducted a 3-stage genome-wide association study (GWAS) using three populations: Japanese from the Japanese Genetic Consortium for Alzheimer Disease (JGSCAD), Koreans, and Caucasians from the Alzheimer Disease Genetic Consortium (ADGC). In Stage 1, we evaluated data for 5,877,918 genotyped and imputed SNPs in Japanese cases (n = 1,008) and controls (n = 1,016). Genome-wide significance was observed with 12 SNPs in the APOE region. Seven SNPs from other distinct regions with p-values <2×10−5 were genotyped in a second Japanese sample (885 cases, 985 controls), and evidence of association was confirmed for one SORL1 SNP (rs3781834, P = 7.33×10−7 in the combined sample). Subsequent analysis combining results for several SORL1 SNPs in the Japanese, Korean (339 cases, 1,129 controls) and Caucasians (11,840 AD cases, 10,931 controls) revealed genome wide significance with rs11218343 (P = 1.77×10−9) and rs3781834 (P = 1.04×10−8). SNPs in previously established AD loci in Caucasians showed strong evidence of association in Japanese including rs3851179 near PICALM (P = 1.71×10−5) and rs744373 near BIN1 (P = 1.39×10−4). The associated allele for each of these SNPs was the same as in Caucasians. These data demonstrate for the first time genome-wide significance of LOAD with SORL1 and confirm the role of other known loci for LOAD in Japanese. Our study highlights the importance of examining associations in multiple ethnic populations.

Brain-derived neurotrophic factor gene polymorphisms and Alzheimer’s disease

Summary.Several lines of evidence have made brain-derived neurotrophic factor (BDNF) an important candidate gene conferring risk for Alzheimer’s disease (AD). Recently, three studies reported an association between two single-nucleotide polymorphisms (SNP) – i.e., C270T and G196A – in the BDNF gene and AD. This attempt to confirm these associations in a larger AD sample included examination of the linkage disequilibrium of these two SNPs. Comparison of 487 Japanese AD subjects with 471 cognitively normal elderly controls showed higher frequencies of the G allele (60.5 vs. 55.5%, p = 0.028) and of both the GG and GA genotypes (85.8 vs. 79.8%, p = 0.025) of the G196A polymorphism in AD subjects than in controls and higher frequency of the T allele of the C270T polymorphism in AD subjects who were negative for apolipotrotein E4 (2.0 vs. 4.4%, p = 0.035) or positive for AD family history (2.8 vs. 7.1%, p = 0.046). These findings suggest that BDNF gene polymorphisms play some role in the development of AD.

Effect of aromatherapy on patients with Alzheimer's disease

Objective:  Recently, the importance of non‐pharmacological therapies for dementia has come to the fore. In the present study, we examined the curative effects of aromatherpay in dementia in 28 elderly people, 17 of whom had Alzheimers disease (AD).

The tottori (D7N) and English (H6R) familial Alzheimer disease mutations accelerate Aβ fibril formation without increasing protofibril formation

A subset of Alzheimer disease cases is caused by autosomal dominant mutations in genes encoding the amyloid β-protein precursor or presenilins. Whereas some amyloid β-protein precursor mutations alter its metabolism through effects on Aβ production, the pathogenic effects of those that alter amino acid residues within the Aβ sequence are not fully understood. Here we examined the biophysical effects of two recently described intra-Aβ mutations linked to early-onset familial Alzheimer disease, the D7N Tottori-Japanese and H6R English mutations. Although these mutations do not affect Aβ production, synthetic Aβ(1-42) peptides carrying D7N or H6R substitutions show enhanced fibril formation. In vitro analysis using Aβ(1-40)-based mutant peptides reveal that D7N or H6R mutations do not accelerate the nucleation phase but selectively promote the elongation phase of amyloid fibril formation. Notably, the levels of protofibrils generated from D7N or H6R Aβ were markedly inhibited despite enhanced fibril formation. These N-terminal Aβ mutations may accelerate amyloid fibril formation by a unique mechanism causing structural changes of Aβ peptides, specifically promoting the elongation process of amyloid fibrils without increasing metastable intermediates.

Estrogen receptor gene polymorphisms in patients with Alzheimer's disease, vascular dementia and alcohol-associated dementia

The association between the estrogen receptor (ER-α) gene and dementia was examined in 223 patients with Alzheimer’s disease (AD), 66 with vascular dementia (VD), 17 with alcohol-associated dementia (ALD) and 134 healthy elderly control subjects. The PvuII and XbaI restriction fragment length polymorphisms of the ER-α gene were represented as Pp (PvuII) and Xx (XbaI), with capital letters signifying the absence of restriction sites and small letters the presence of restriction sites. We found that the frequency of the ER-α gene P allele and X allele in the late-onset AD (LOAD) group (P allele was 0.51, X allele was 0.30) was significantly higher than that in controls (P 0.38, p < 0.01; X 0.20, p < 0.01), and that the frequency of the ER-α gene P allele and PP genotype was significantly different between apolipoprotein E ε4 carriers and noncarriers in LOAD. These findings suggest that the genotype of the ER-α gene may be specific in LOAD, and that the ER-α gene was an additional risk for LOAD.