The correlation of small fiber neuropathy with pain intensity and age in patients with Fabry's disease: A cross sectional study within a large Taiwanese family.

BACKGROUND: The relationships among small fiber neuropathy, age, sex and pain intensity in the context of Fabry's disease remain unclear. We aim to study the correlations of small fiber neuropathy, age, sex and pain intensity in Fabry patients. METHODS: We evaluated C-fiber function by recording the withdrawal latencies to painful heat stimulus (WLPHS) when each subject's right hand was immersed in a 50 °C hot water bath and correlated this parameter with the patient's perceived pain intensity and quality of life assessed by the short-form McGill Pain Questionnaire (SF-MPQ) in a large Taiwanese Fabry family and normal controls. RESULTS: Male Fabry patients showed a significantly increased WLPHS compared to that of normal controls. Furthermore, male Fabry patients showed a positive correlation of increased WLPHS with patient age. The SF-MPQ of male Fabry patients showed a bell distribution with age, and maximal pain scores were detected between the ages of the early 20s and late 40s. In contrast, the female Fabry patients had variable associations of WLPHS and SF-MPQ with age. CONCLUSIONS: We proposed a probable mechanism by which globotriaosylceramide (Gb3) or globotriaosylsphingosine (lyso-Gb3) is gradually deposited into the small nerve bundles with increasing age, which induces continuous damage and produces injury discharges to sustain neuropathic pain in young male Fabry patients. However, once the small fibers are reduced to a certain degree, they no longer produce enough noxious discharges to sustain neuropathic pains in older male Fabry patients, which leads these patients to have lower SF-MPQ scores. In contrast, female Fabry patients had less and variable small fiber damage, pain intensity and clinical signs/symptoms.

Association of AXIN1 With Parkinson's Disease in a Taiwanese Population.

OBJECTIVE: A meta-analysis of locus-based genome-wide association studies recently identified a relationship between AXIN1 and Parkinson's disease (PD). Few studies of Asian populations, however, have reported such a genetic association. The influences of rs13337493, rs758033, and rs2361988, three PD-associated genetic variants of AXIN1, were investigated in the present study because AXIN1 is related to Wnt/ß-catenin signaling. METHODS: A total of 2,418 individuals were enrolled in our Taiwanese cohort for analysis of the genotypic and allelic frequency. Polymerase chain reaction-restriction fragment length polymorphism analysis was employed for rs13337493 genotyping, and the Agena MassARRAY platform (Agena Bioscience, San Diego, CA, USA) was used for rs758033 and rs2361988 genotyping in 672 patients with PD and 392 controls. Taiwan Biobank data of another 1,354 healthy controls were subjected to whole-genome sequencing performed using Illumina platforms at approximately 30× average depth. RESULTS: Our results revealed that rs758033 {odds ratios [OR] (95% confidence interval [CI]) = 0.267 [0.064, 0.795], p = 0.014} was associated with the risk of PD, and there was a trend toward a protective effect of rs2361988 (OR [95% CI] = 0.296 [0.071, 0.884], p = 0.026) under the recessive model. The TT genotype of rs758033 (OR [95% CI] = 0.271 [0.065, 0.805], p = 0.015) and the CC genotype of rs2361988 (OR [95% CI] = 0.305 [0.073, 0.913], p = 0.031) were less common in the PD group than in the non-PD group. CONCLUSION: Our findings indicate that the rs758033 and rs2361988 polymorphisms of AXIN1 may affect the risk of PD in the Taiwanese population.

Polymorphisms of Interleukin-6 and Interleukin-8 Are Not Associated with Parkinson's Disease in Taiwan.

BACKGROUND: Studies have suggested that cytokines are crucial mediators in the pathogenesis of Parkinson's disease (PD). The multifunctional cytokine interleukin (IL)-6 and its single nucleotide polymorphisms (SNPs) were found to have an impact on the development of PD. However, different studies in associations of IL-6 genetic variants with PD showed inconsistent results and it has never been explored in a Taiwanese population. Both IL-1α and IL-8 contribute to the same inflammation pathway. IL-1α genetic polymorphism has an effect on late-onset PD in Taiwan, whereas the associations of IL-8 genetic variants with PD in Taiwan remain to be investigated. METHODS: This study examined the frequencies of polymorphisms within the critical promoter areas of the proinflammatory cytokine genes: IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) in Taiwanese PD patients compared with age-and gender-matched healthy subjects. Comparisons were also made in genotype and allele frequencies of IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) among different populations in previous studies. RESULTS: In total, 1120 subjects, including 509 PD patients (female/male: 259/250) and 511 control subjects (female/male: 252/259), were recruited. We found no statistically significant differences in IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) genotypic and allelic distribution between PD and controls, even after being stratified by age at onset and gender. CONCLUSIONS: The results did not demonstrate any association of IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) with PD in a Taiwanese population. Despite the negative results, this is the first study in associations of IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) with PD in Taiwan. The relevance of genetic variants of IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) on PD susceptibility warrants further investigation.

Role of LRP10 in Parkinson's disease in a Taiwanese cohort.

INTRODUCTION: Variants in the low-density lipoprotein receptor-related protein 10 (LRP10), linked to inherited forms of α-synucleinopathies, have been reported. Nine variants of LRP10 were identified in the first such report, and subsequent studies have identified possible pathogenic variants in patients with sporadic Parkinson's disease (PD). Few studies have investigated the role of LRP10 in PD. We sought to validate the role of this gene in Taiwanese patients with PD. METHODS: In total, 1277 individuals were included in this study (669 had PD and 608 were controls). The entire LRP10 coding exons and exon-intron boundaries were sequenced in 103 probands with early-onset PD or familial PD. We then genotyped the newly identified variants from the 103 patients and previously reported potential pathogenic variants in our cohort. The frequencies of variants were analyzed. RESULTS: Five new and possibly pathogenic variants were identified initially. In total, 14 potentially pathogenic variants (including nine previously reported and five newly identified variants) were analyzed thereafter. We did not find any significant associations between any variant and the risk of PD. However, c.1424+5delG was identified in a patient with sporadic PD who was diagnosed as having PD and dementia and who had prominent psychiatric symptoms. CONCLUSION: Although we identified a patient with sporadic PD and dementia carrying a c.1424+5delG variant, our data did not provide sufficient evidence to support the role of LRP10 in PD in Taiwanese adults.

Fibroblast Growth Factor 20 Gene Polymorphism in Parkinson's Disease in Asian Population: A Meta-Analysis.

Parkinson's disease (PD) is a neurodegenerative disease with the pathological hallmark of Lewy bodies and Lewy neurites composed of α-synuclein. The SNP rs591323 is one of the risk loci located near the FGF20 gene that has been implicated in PD. The variation of FGF20 in the 3' untranslated region was shown to increase α-synuclein expression. We examined the association of rs591323 with the risk of PD in a Taiwanese population and conducted a meta-analysis, including our study and two other studies from China, to further confirm the role of this SNP in Taiwanese/Chinese populations. A total of 586 patients with PD and 586 health controls (HCs) were included in our study. We found that the minor allele (A) and the AA + GA genotype under the dominant model are significantly less frequent in PD than in controls. The meta-analysis consisted of 1950 patients with PD and 2073 healthy controls from three studies. There was significant association between rs591323 and the risk of PD in the additive (Z = -3.96; p < 0.0001) and the dominant models (Z = -4.01; p < 0.0001). Our study results and the meta-analysis support the possible protective role of the rs591323 A allele in PD in Taiwanese/Chinese populations.

Association of genetic variants within HLA-DR region with Parkinson's disease in Taiwan.

Previous genome-wide association studies in Caucasians suggest genetic loci of human leukocyte antigen (HLA)-DR region may be associated with Parkinson's disease (PD). However, these gene-disease associations were limitedly reported in Asian populations. Herein, we investigated the effects of 5 top PD-associated genetic variants within HLA-DR region in Caucasians, including rs4248166, rs9268515, rs2395163, rs75855844, and rs660895, by genotyping 486 Taiwanese patients with PD and 473 age-matched control subjects. Although the association between rs2395163 C allele and patients with PD demonstrated marginal significance (odds ratio [OR] = 0.74, 95% CI: 0.55-0.99, p = 0.045). The frequency of rs2395163 C allele (8.65%) in male patients with PD was significantly lower than in male control subjects (14.02%; OR = 0.58, 95% CI: 0.39-0.88, p = 0.009). The genetic associations between patients with PD and other tested genetic variants were negative. Although strong linkage disequilibrium (rs4248166-rs9626515-s2395163 and rs9626515-rs660895) were observed, the haplotype analysis did not find any significant risk-associated allelic combinations. These results suggest a distinct genetic background within HLA-DR region between Taiwanese and Caucasian patients with PD.

Association of RIT2 and RAB7L1 with Parkinson's disease: a case-control study in a Taiwanese cohort and a meta-analysis in Asian populations.

Several genome-wide association studies and meta-analyses on Parkinson's disease (PD)-related genes have identified several risk foci in Ras-related genes, particularly among Caucasian individuals. However, the corresponding results have been controversial among Asian individuals. We investigated whether 2 single-nucleotide polymorphisms of Ras-related genes, RIT2 (rs12456492) and RAB7L1 (rs823118), are associated with PD risk in Taiwanese individuals. In addition, we conducted a meta-analysis of all studies related to rs12456492 in Asian populations to resolve inconsistency in this locus. In total, 1103 Taiwanese individuals (588 patients with PD and 515 controls) and 1111 Taiwanese individuals (594 patients with PD and 517 controls) were genotyped for rs12456492 and rs823118. However, we could not confirm the association of rs12456492 and rs823118 with PD. Our current meta-analysis involving the rs12456492(A/G) variant demonstrated that the GG + GA genotypes, GG genotypes, and G allele may be risk factors for PD. RIT2 may increase PD risk in Asian individuals. The discrepancies between Caucasian and Asian populations may be due to differences in geographic region-specific genetic backgrounds and gene-environmental interactions.

CCM1 and CCM2 variants in patients with cerebral cavernous malformation in an ethnically Chinese population in Taiwan.

Cerebral cavernous malformation (CCM) is a vascular malformation characterized by clustered enlarged capillary-like channels in the central nervous system. The genes harboring variants in patients with CCM include CCM1/Krev interaction trapped-1, CCM2/MGC4607, and CCM3/programmed cell death protein 10. We aimed to identify pathogenic variants in an ethnic Chinese population in Taiwan. We recruited 95 patients with multiple CCMs or a single lesion with a relevant family history. Sanger sequencing was performed for 41 patients. Variants were identified using sequence alignment tools, and the clinical significance of these variants was determined using American College of Medical Genetics and Genomics standards and guidelines. Several pathogenic variants were found in six patients, including three unrelated patients and three affected members of one family. Two novel pathogenic variants leading to early truncation comprised a deletion variant in exon 18 of CCM1 (c.1846delA; p.Glu617LysfsTer44) and an insertion variant in exon 4 of CCM2 (c.401_402insGCCC; p.Ile136AlafsTer4). One novel pathogenic splice site variant was c.485 + 1G > C at the beginning of intron 8 of CCM1. In this study, we identified novel variants related to CCM in an ethnically Chinese population in Taiwan.

Polymorphisms of ACMSD-TMEM163, MCCC1, and BCKDK-STX1B Are Not Associated with Parkinson's Disease in Taiwan.

Previous genome-wide association studies in Caucasian populations suggest that genetic loci in amino acid catabolism may be associated with Parkinson's disease (PD). However, these genetic disease associations were limitedly reported in Asian populations. Herein, we investigated the effect of top three PD-associated genetic variants related to amino acid catabolism in Caucasians listed on the top risk loci identified by meta-analysis of genome-wide association studies in PDGene database, including aminocarboxymuconate-semialdehyde decarboxylase- (ACMSD-) transmembrane protein 163 (TMEM163) rs6430538, methylcrotonyl-CoA carboxylase 1 (MCCC1) rs12637471, and branched-chain ketoacid dehydrogenase kinase- (BCKDK-) syntaxin 1B (STX1B) rs14235, by genotyping 599 Taiwanese patients with PD and 598 age-matched control subjects. PD patients demonstrate similar allelic and genotypic frequencies in all tested genetic variants. These ethnic discrepancies of genetic variants suggest a distinct genetic background of amino acid catabolism between Taiwanese and Caucasian PD patients.

Amyloid PET pattern with dementia and amyloid angiopathy in Taiwan familial AD with D678H APP mutation.

INTRODUCTION: The novel D678H amyloid precursor protein (APP) gene mutation has been called the "Taiwan mutation". The study aims to identify amyloid deposition patterns and clinical features associated with this mutation. METHODS: we analyzed the clinical manifestations, brain neuroimages and 18F-AV-45 positron emission tomography (PET) findings in symptomatic patients and asymptomatic subjects with the autosomal-dominant Alzheimer's disease (AD). We compared the amyloid deposition pattern among 10 patients with genetically-positive familial cognitive decline (CD), 18 patients with sporadic CD, and 19 healthy controls. RESULTS: The clinical features were the early onset of memory impairment in all 10 patients and cerebral amyloid angiopathy in 3 patients. The characteristic results of brain 18F-AV-45 PET included the highest standard uptake value ratio (SUVR) in the occipital and cerebellar cortical areas in the genetically-positive CD patients. In subgroup analysis, the familial AD patients had a decreased amyloid SUVR trend in most areas except for cerebellar cortex compared to those with familial mild cognitive impairment. CONCLUSION: Our data indicate that the familial D678H gene mutation have resulted in a more potent amyloid burden than in the patients with sporadic AD patients. The high amyloid uptake in the occipital area is characteristic of the specific Taiwan APP gene.

DLG2, but not TMEM229B, GPNMB, and ITGA8 polymorphism, is associated with Parkinson's disease in a Taiwanese population.

Transmembrane or membrane-associated protein dysfunction is increasingly recognized as an important mechanism of pathogenesis in Parkinson's disease (PD). Previous genome-wide association studies and their meta-analysis in PD genes have identified several risk foci in transmembrane protein-encoding genes. Herein, we investigated the effect of 4 such PD-associated genetic variants reported in Caucasians, including discs-large membrane-associated guanylate kinase scaffolding protein 2 (DLG2 rs3793947), transmembrane protein 229B (TMEM229B rs1555399), glycoprotein nonmetastatic melanoma protein B (GPNMB rs199347), and integrin subunit alpha 8 (ITGA8 rs7077361). A total of 1185 Taiwanese subjects comprising 592 PD patients and 593 unrelated age-matched controls were genotyped. DLG2 rs3793947 AA genotype showed a significantly lower prevalence in female PD patients compared to the female controls (p = 0.019). The recessive model analysis also demonstrated a reduced PD risk for females in AA genotype (odds ratio = 0.573, 95% confidence interval: 0.379-0.868, p = 0.008). The frequencies of TMEM229B rs1555399 and GPNMB rs199347 genotypes and alleles were similar in PD patients and controls. ITG8 rs7077361 was not polymorphic in all subjects of this study. These data suggested that DLG2, but not TMEM229B, GPNMB, and ITGA8, influenced the risk of PD in Taiwan.

The Potential of Indole/Indolylquinoline Compounds in Tau Misfolding Reduction by Enhancement of HSPB1.

BACKGROUND: Neurofibrillary tangles formed from tau misfolding have long been considered one of the pathological hallmarks of Alzheimer's disease (AD). The misfolding of tau in AD correlates with the clinical progression of AD and inhibition or reversal of tau misfolding may protect the affected neurons. METHODS: We generated 293 and SH-SY5Y cells expressing DsRed-tagged pro-aggregation mutant of repeat domain of tau (ΔK280 tauRD ) to test indole/indolylquinoline derivatives for reducing tau misfolding and neuroprotection. RESULTS: Four of the 10 derivatives tested displayed good misfolding-inhibitory effects on Tet-On 293 cells. Among them, NC009-1 and NC009-7 enhanced heat-shock 27 kDa protein 1 (HSPB1) expression to increase ∆K280 tauRD -DsRed solubility and promoted neurite outgrowth in Tet-On SH-SY5Y cells. Knockdown of HSPB1 resulted in decreased ∆K280 tauRD -DsRed solubility and reduced neurite outgrowth, which were rescued by addition of NC009-1/NC009-7. Treatment with indole/indolylquinoline derivatives also improved neuronal cell viability and neurite outgrowth in mouse hippocampal primary culture under tau cytotoxicity. CONCLUSION: Our results demonstrate how indole/indolylquinoline derivatives are likely to work in tau misfolding reduction, providing insight into the possible working mechanism of indole and indolylquinoline derivatives in AD treatment.

Digit symbol substitution test score and hyperhomocysteinemia in older adults.

Mounting evidence shows that hyperhomocysteinemia is a risk factor for cognitive decline. This study enrolled subjects with normal serum levels of B12 and folate and performed thorough neuropsychological assessments to illuminate the independent role of homocysteine on cognitive functions.Participants between ages 50 and 85 were enrolled with Modified Hachinski ischemic score of <4, adequate visual and auditory acuity to allow neuropsychological testing, and good general health. Subjects with cognitive impairment resulting from secondary causes were excluded. Each of the participants completed evaluations of general intellectual function, including the Mini-Mental State Examination, Cognitive Abilities Screening Instrument, Clinical Dementia Rating, and a battery of neuropsychological assessments.This study enrolled 225 subjects (90 subjects younger than 65 years and 135 subjects aged 65 years or older). The sex proportion was similar between the 2 age groups. Years of education were significantly fewer in the elderly (7.49 ±â€Š5.40 years) than in the young (9.76 ±â€Š4.39 years, P = 0.001). There was no significant difference in body mass index or levels of vitamin B12 and folate between the 2 age groups. Homocysteine levels were significantly higher in the elderly group compared to the younger group (10.8 ±â€Š2.7 vs. 9.5 ±â€Š2.5 µmol/L, respectively, P = 0.0006). After adjusting for age, sex, and education, only the Digit Symbol Substitution (DSS) score was significantly lower in subjects with hyperhomocysteinemia (homocysteine >12 µmol/L) than those with homocysteine ≤12 µmol/L in the elderly group (DSS score: 7.1 ±â€Š2.7 and 9.0 ±â€Š3.0, respectively, beta = -1.6, 95% confidence interval [CI] = -2.8∼-0.5, P = 0.001) and borderline significance was noted in the combined age group (beta = -1.1, 95% CI = -2.1∼-0.1, P = 0.04). We did not find an association between hyperhomocysteinemia and other neuropsychological assessments.This is the first study to demonstrate a significant association between hyperhomocysteinemia (>12 µmol/L) and low DSS score, suggesting that DSS score may be an independent marker of cognitive impairment in response to hyperhomocysteinemia, especially in the elderly. Further replication studies with larger cohorts are needed to confirm our results.

Association of GCH1 and MIR4697, but not SIPA1L2 and VPS13C polymorphisms, with Parkinson's disease in Taiwan.

Recently, a large-scale meta-analysis of genome-wide association study (GWAS) data identified several new risk loci that can modulate the risk of Parkinson's disease (PD). These associations have yet to be examined in PD patients in Chinese or Asian population. Because ethnic-specific effect is an important concern for GWAS analysis, we genotyped single-nucleotide polymorphisms in the new genetic loci, GCH1 (rs11158026), SIPA1L2 (rs10797576), VPS13C (rs2414739), and MIR4697 (rs329648), to investigate their associations with risk of PD in Taiwan. Another single-nucleotide polymorphism GCH1 rs7155501, previously identified by GWAS listed at the top 20 genes in PDGene database was also included. A total of 1151 study subjects comprising 598 patients with PD and 553 unrelated healthy controls were recruited. The frequency of minor allele (C allele) of GCH1 rs11158026 was found to be significantly higher in PD cases than in controls (p = 0.003). The CC genotype of rs11158026 increased PD risk compared to TT genotype (odds ratio [OR] = 1.29, 95% confidence interval [CI] = 1.09, 1.53, p = 0.004). Under additive model, the GCH1 rs11158026 increased the risk of developing PD (OR = 1.30, 95% CI = 1.10, 1.54, p = 0.002). In recessive model, the genotype TT of MIR4697 rs329648 marginally decreased the PD risk (OR = 0.62, 95% CI = 0.43, 0.90, p = 0.01). The PD patients demonstrated similar genotypic and allelic frequencies in GCH1 rs7155501, SIPA1L2 rs10797576, and VPS13C rs2414739 with the controls. These findings suggest that the GCH1 and MIR4697 but not SIPA1L2 and VPS13C are genetic loci influencing risk of PD in Taiwan.

The potential of synthetic indolylquinoline derivatives for Aß aggregation reduction by chemical chaperone activity.

Alzheimer's disease (AD) is the most prevalent form of dementia associated with progressive cognitive decline and memory loss. Extracellular ß-amyloid (Aß) is a major constituent of senile plaques, one of the pathological hallmarks of AD. Aß deposition causes neuronal death via a number of possible mechanisms such as increasing oxidative stress. Therefore therapeutic approaches to identify novel Aß aggregate reducers could be effective for AD treatment. Using a Trx-His-Aß biochemical assay, we screened 11 synthetic indolylquinoline compounds, and found NC009-1, -2, -6 and -7 displaying potential to reduce Aß aggregation. Treating Tet-On Aß-GFP 293 cells with these compounds reduced Aß aggregation and reactive oxygen species. These compounds also promoted neurite outgrowth in Tet-On Aß-GFP SH-SY5Y cells. Furthermore, treatment with above compounds improved neuronal cell viability, neurite outgrowth, and synaptophysin expression level in mouse hippocampal primary culture under oligomeric Aß-induced cytotoxicity. Moreover, the tested NC009-1 significantly ameliorated Aß-induced inhibition of hippocampal long-term potentiation in mouse hippocampal slices. Our results demonstrate how synthetic indolylquinoline compounds are likely to work as chemical chaperones in Aß-aggregation reduction and neuroprotection, providing insight into the possible applications of indolylquinoline compounds in AD treatment.

Eukaryotic translation initiation factor 4-γ, 1 gene mutations are rare in Parkinson's disease among Taiwanese.

BACKGROUND/PURPOSE: Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide. Although idiopathic PD accounts for most of the cases, several genetic mutations have been found to cause PD. Mutations in the eukaryotic translation initiation factor 4-γ, 1 (EIF4G1) gene have been identified since 2011, which were reported to be associated with PD among Caucasians in subsequent research. However, this observation was not consistent. The contribution to other ethnic groups remains limited, with < 1% of sporadic cases. We conducted a case-control study to analyze if EIF4G1 is a risk factor for PD patients in Taiwan. METHODS: There were 595 PD patients and 600 controls without neurological diseases enrolled in this study. Four reported mutations-A502V (c.1505C>T), G686C (c.2056 G>T), R1197W (c.3589C>T), and R1205H (c.3614G>A)-were analyzed. RESULTS: There were no mutations found in either PD patients or controls. CONCLUSION: This study indicates that the EIF4G1 mutation is rare in Taiwan, which is consistent with other reports from Asia. Ethnicity could have a great influence on EIF4G1 in PD. Further large scale studies are warranted to evaluate the association of PD and EIF4G1 gene.

STK39, But Not BST1, HLA-DQB1, and SPPL2B Polymorphism, Is Associated With Han-Chinese Parkinson's Disease in Taiwan.

Neuroinflammation is emerging as an important pathway involved in Parkinson's disease (PD) pathogenesis. Herein, we investigated the effect of 4 top PD-associated genetic variants in Caucasians listed on the top risk loci identified by meta-analysis of genome wide-association studies in PDGene database (http://www.pdgene.org/top_results), including serine threonine kinase 39 (STK39) rs1955337, bone marrow stromal cell antigen 1 (BST1) rs11724635, major histocompatibility complex, class II, DQ beta 1 (HLA-DQB1) rs9275326, and signal peptide peptidase-like 2B (SPPL2B) rs62120679, by genotyping 596 Han-Chinese patients with PD and 597 age-matched control subjects. Compared with subjects with STK39 rs1955337 GG genotype, those with TT genotype had a 1.64-fold increased risk of PD (95% confidence interval: 1.13-2.39, P = 0.010). The recessive model also demonstrated an increased PD risk in TT genotype (odds ratio: 1.59, 95% confidence interval: 1.12-2.27) compared with the other genotypes (GT + GG). PD patients demonstrate a similar genotypic and allelic frequency in BST1 rs11724635, HLA-DQB1 rs9275326, and SPPL2B rs62120679 compared with controls. These findings suggested that the STK39 rs1955337 TT genotype is a risk factor for Han-Chinese patients with PD in Taiwan. The ethnic discrepancies of the other 3 genetic variants may indicate a distinct genetic background of neuroinflammation between PD patients in Han-Chinese and Caucasians.

Tract-based spatial statistics: application to mild cognitive impairment.

RATIONALE AND OBJECTIVES: The primary objective of the current investigation was to characterize white matter integrity in different subtypes of mild cognitive impairment (MCI) using tract-based spatial statistics of diffusion tensor imaging. MATERIALS AND METHODS: The study participants were divided into 4 groups of 30 subjects each as follows: cognitively healthy controls, amnestic MCI, dysexecutive MCI, and Alzheimer's disease (AD). All subjects underwent a comprehensive neuropsychological assessment, apolipoprotein E genotyping, and 3-tesla MRI. The diffusion tensor was reconstructed and then analyzed using tract-based spatial statistics. The changes in brain white matter tracts were also examined according to the apolipoprotein E ε 4 status. RESULTS: Compared with controls, amnestic MCI patients showed significant differences in the cerebral white matter, where changes were consistently detectable in the frontal and parietal lobes. We found a moderate impact of the apolipoprotein E ε 4 status on the extent of white matter disruption in the amnestic MCI group. Patients with AD exhibited similar but more extensive alterations, while no significant changes were observed in dysexecutive MCI patients. CONCLUSION: The results from this study indicate that amnestic MCI is the most likely precursor to AD as both conditions share significant white matter damage. By contrast, dysexecutive MCI seems to be characterized by a distinct pathogenesis.

Structural study of the microtubule-associated protein tau locus of Alzheimer's disease in Taiwan.

BACKGROUND: Haplotype structure of the microtubule-associated protein tau (MAPT) gene is associated with various tauopathies in the Caucasian population. With the knowledge that the association between MAPT structure and disease may be distinct in different ethnics, we intend to investigate the haplotype structure of MAPT in Taiwanese and test it for association with Alzheimer's disease (AD). METHODS: One hundred and eight AD patients and 108 sex- and-age matched healthy controls were recruited from the dementia outpatient clinic of Chang Gung Medical center. We genotyped the del-In9 marker that defines the extended H1 and H2 clades. We selected 21 single-nucleotide polymorphisms (SNPs) in the extended MAPT region from Japanese SNPs database and dbSNP database. Using the software TagIt, we analyzed the linkage disequilibrium structure of MAPT and compared the allele and genotype distribution between patient group and control group. RESULTS: All the Taiwanese participants were H1 haplotypes. Linkage disequilibrium analysis showed the haplotype blocks in Taiwanese population had a smaller size in comparison to that of the Caucasian population. Single locus association showed significant p value in one of the tagging variants (rs242557) in our Taiwanese AD case-control cohorts. CONCLUSION: MAPT gene has four haplotype blocks in the Taiwanese population, each of around 40 kbp. In both European study and our study, the SNP rs242557 showed association with AD. Given the position of this SNP, the most possible explanation is that genetic variability in tau expression contributes to the risk of developing AD.