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Authors: Boutté, Angela M. | Neely, M. Diana | Bird, Thomas D. | Montine, Kathleen S. | Montine, Thomas J.

Article Type: Research Article

Abstract: Neuronal microtubules are morphologically abnormal in diseased regions of brain from patients with late-onset Alzheimer's disease (LOAD). Here we tested the hypothesis that tubulin derived from gray matter of patients with multiple forms of dementia was functionally impaired. Following taxol/GTP stimulation of tubulin polymerization of gray matter extracts we observed reduced capacity of tubulin to polymerize in LOAD, but not individuals with mild cognitive impairment (MCI), compared to controls. Moreover, we observed similarly reduced taxol/GTP-stimulated tubulin polymerization from gray matter obtained from patients with AD caused by PSEN2 N141I mutation or frontotemporal dementia with parkinsonism linked to chromosome-17 caused (FTDP-17) …by TAU V337M or P301L mutation. Our results show that modification of tubulin function may contribute to intermediate or late stages in the pathogenesis of sporadic and inherited AD as well as FTDP-17. Show more

Keywords: Alzheimer's disease, presenilin 2, frontotemporal dementia with parkinsonism linked to chromosome-17, mild cognitive impairment, tubulin, microtubules

DOI: 10.3233/JAD-2005-8101

Citation: Journal of Alzheimer's Disease, vol. 8, no. 1, pp. 1-6, 2005

Authors: Tsuang, Debby W. | Greenwood, Tiffany A. | Jayadev, Suman | Davis, Marie | Shutes-David, Andrew | Bird, Thomas D.

Article Type: Research Article

Abstract: Background: Psychotic symptoms of delusions and hallucinations occur in about 5% of persons with Huntington’s disease (HD). The mechanisms underlying these occurrences are unknown, but the same symptoms also occur in schizophrenia, and thus genetic risk factors for schizophrenia may be relevant to the development of psychosis in HD. Objective: To investigate the possible role of genes associated with schizophrenia in the occurrence of psychotic symptoms in HD. Methods: DNA from subjects with HD and psychosis (HD+P; n  = 47), subjects with HD and no psychosis (HD-P; n  = 126), and controls (CTLs; n  = 207) was genotyped using the Infinium PsychArray-24 v1.1 …BeadChip. The allele frequencies of single-nucleotide polymorphisms (SNPs) that were previously associated with schizophrenia and related psychiatric disorders were compared between these groups. Results: Of the 30 candidate genes tested, 10 showed an association with psychosis in HD. The majority of these genes, including CTNNA2 , DRD2 , ERBB4 , GRID2 , GRIK4 , GRM1 , NRG1 , PCNT , RELN , and SLC1A2 , demonstrate network interactions related to glutamate signaling. Conclusions: This study suggests genetic associations between several previously identified candidate genes for schizophrenia and the occurrence of psychotic symptoms in HD. These data support the potential role of genes related to glutamate signaling in HD psychosis. Show more

Keywords: Delusions, genetic association studies, genetic predisposition to disease, genetics, glutamates, hallucinations, Huntington disease, modifier genes, psychotic disorders, schizophrenia

DOI: 10.3233/JHD-170277

Citation: Journal of Huntington's Disease, vol. 7, no. 1, pp. 51-59, 2018

Authors: Tsuang, Debby W. | Riekse, Robert G. | Purganan, Kristina M. | David, Andrew C. | Montine, Thomas J. | Schellenberg, Gerard D. | Steinbart, Ellen J. | Petrie, Eric C. | Bird, Thomas D. | Leverenz, James B.

Article Type: Research Article

Abstract: Background: Lewy body pathology (LBP) is a common finding in Alzheimer's disease (AD), but the pathophysiology for this coexistent pathology remains unclear. Methods: We ascertained late-onset dementia (mean age > 60 years old) families with at least 3 autopsies. We then conducted systematic alpha-synuclein (SNCA) immunostaining to determine the frequency and distribution of LBP in families with late-onset AD. Results: All 32 subjects met NIA-Reagan neuropathological criteria for “high likelihood” of having AD. Hematoxylin and eosin staining detected LBP in the substantia nigra (SN) in 8 (25%) individuals. SNCA immunostaining detected LBP in 21 individuals (66%). While all subjects with …SN LBP had co-existent amygdala LBP, many (9/21, 43%) of the cases with amygdala LBP did not have coexistent SN LBP (McNemar's chi-square test, p=0.008). Each family had at least two cases with LBP, but no family had LBP in all autopsied cases. Conclusions: Presence of significant AD pathology in one family member was highly predictive of similar pathology in other family members. However, despite the use of more sensitive SNCA immunohistochemistry, the presence of LBP was variable within all 7 families. Consistent with previous studies in sporadic and familial AD, the amygdala appeared to be the most vulnerable region for LBP in AD. Additional clinical, neuropathologic, and genetic studies are necessary to determine the clinical and pathological significance of LBP in AD. Show more

Keywords: Lewy body, alpha-synuclein, Alzheimer's disease, amygdala

DOI: 10.3233/JAD-2006-9302

Citation: Journal of Alzheimer's Disease, vol. 9, no. 3, pp. 235-242, 2006

Authors: Wilson, Robert S. | Barral, Sandra | Lee, Joseph H. | Leurgans, Sue E. | Foroud, Tatiana M. | Sweet, Robert A. | Graff-Radford, Neill | Bird, Thomas D. | Mayeux, Richard | Bennett, David A. | for the National Institute on Aging Late-Onset Alzheimer's Disease Genetics Study

Article Type: Research Article

Abstract: The study aim was to estimate the genetic contribution to individual differences in different forms of memory in a large family-based group of older adults. As part of the Late Onset Alzheimer's Disease Family Study, 899 persons (277 with Alzheimer's disease, 622 unaffected) from 325 families completed a battery of memory tests from which previously established composite measures of episodic memory, semantic memory, and working memory were derived. Heritability in these measures was estimated using the maximum likelihood variance component method, controlling for age, gender, and education. In analyses of unaffected family members, the adjusted heritability estimates were 0.62 for …episodic memory, 0.49 for semantic memory, and 0.72 for working memory, where a heritability estimate of 1 indicates that genetic factors explain all of the phenotypic variance and a heritability of 0 indicates that genetic factors explain none. Adjustment for APOE genotype had little effect on these estimates. When analyses included affected and unaffected family members, adjusted heritability estimates were lower (0.47 for episodic memory, 0.32 for semantic memory, 0.42 for working memory). Adjusting for APOE slightly reduced the estimate for episodic memory (0.40) but had no effect on the remaining estimates. The results indicate that memory functions are under strong genetic influence in older persons with and without AD, and are only partly attributable to APOE. This suggests that genetic analyses of memory endophenotypes may help to identify genetic variants associated with AD. Show more

Keywords: Alzheimer's disease, apolipoprotein E, heritability, memory

DOI: 10.3233/JAD-2010-101515

Citation: Journal of Alzheimer's Disease, vol. 23, no. 2, pp. 249-255, 2011

Authors: Latimer, Caitlin S. | Flanagan, Margaret E. | Cimino, Patrick J. | Jayadev, Suman | Davis, Marie | Hoffer, Zachary S. | Montine, Thomas J. | Gonzalez-Cuyar, Luis F. | Bird, Thomas D. | Keene, C. Dirk

Article Type: Research Article

Abstract: Background: Huntington’s disease (HD) is an autosomal dominant neurodegenerative disease caused by a trinucleotide (CAG) repeat expansion in huntingtin (HTT ) on chromosome 4. Anticipation can cause longer repeat expansions in children of HD patients. Juvenile Huntington’s disease (JHD), defined as HD arising before age 20, accounts for 5–10% of HD cases, with cases arising in the first decade accounting for approximately 1%. Clinically, JHD differs from the predominately choreiform adult onset Huntington’s disease (AOHD) with variable presentations, including symptoms such as myoclonus, seizures, Parkinsonism, and cognitive decline. Objective: The neuropathologic changes of AOHD are well characterized, but there are …fewer reports that describe the neuropathology of JHD. Here we report a case of a six-year-old boy with paternally-inherited JHD caused by 169 CAG trinucleotide repeats who presented at age four with developmental delay, dysarthria, and seizures before dying at age 6. The boy’s clinical presentation and neuropathological findings are directly compared to those of his father, who presented with AOHD and 54 repeats. Methods: A full autopsy was performed for the JHD case and a brain-only autopsy was performed for the AOHD case. Histochemically- and immunohistochemically-stained slides were prepared from formalin-fixed, paraffin-embedded tissue sections. Results: Both cases had neuropathology corresponding to Vonsattel grade 3. The boy also had cerebellar atrophy with huntingtin-positive inclusions in the cerebellum, findings not present in the father. Conclusions: Autopsies of father and son provide a unique opportunity to compare and contrast the neuropathologic findings of juvenile and adult onset HD while also providing the first immunohistochemical evidence of cerebellar involvement in JHD. Additionally this is the first known report to include findings from peripheral tissue in a case of JHD. Show more

Keywords: Autopsy, huntingtin protein, Huntington’s disease, immunohistochemistry, juvenile Huntington’s disease, literature review, neuropathology

DOI: 10.3233/JHD-170261

Citation: Journal of Huntington's Disease, vol. 6, no. 4, pp. 337-348, 2017

Authors: Pearl, Jocelynn R. | Heath, Laura M. | Bergey, Dani E. | Kelly, John P. | Smith, Corrie | Laurino, Mercy Y. | Weiss, Avery | Price, Nathan D. | LaSpada, Albert | Bird, Thomas D. | Jayadev, Suman

Article Type: Research Article

Abstract: Background: Huntington’s disease (HD) is a fatal progressive neurodegenerative disease characterized by chorea, cognitive impairment and psychiatric symptoms. Retinal examination of HD patients as well as in HD animal models have shown evidence of retinal dysfunction. However, a detailed retinal study employing clinically available measurement tools has not been reported to date in HD. Objective: The goal of this study was to assess retinal responses measured by electroretinogram (ERG) between HD patients and controls and evaluate any correlation between ERG measurements and stage of disease. Methods: Eighteen patients and 10 controls with inclusion criteria of ages 18–70 years (average age …HD subjects: 52.1 yrs and control subjects: 51.9 yrs) were recruited for the study. Subjects with previous history of retinal or ophthalmologic disease were excluded. Retinal function was examined by full-field ERG in both eyes of each subject. Amplitudes and latencies to increasing flash intensities in both light- and dark-adaptation were measured in all subjects. Statistical analyses employed generalized estimating equations, which account for repeated measures per subject. Results: We analyzed the b-wave amplitudes of ERG response in all flash intensities and with 30 Hz flicker stimulation. We found statistically significant increased amplitudes in HD patients compared to controls at light-adapted (photopic) 24.2 and 60.9 cd.sec/m2 intensities, dark-adapted (scotopic, red flash) 0.22 cd.sec/m2 intensity, and a trend toward significance at light-adapted 30 Hz flicker. Furthermore, we found a significant increase in light-adapted ERG response from female compared to male HD patients, but no significant difference between gender amongst controls. We also noted a positive association between number of CAG repeats and ERG response at the smallest light adapted intensity (3.1 cd.sec/m2 ). Conclusions: ERG studies revealed significantly altered retinal responses at multiple flash intensities in subjects with an HD expansion allele compared to controls. Significant differences were observed with either light-adapted tests or the dark-adapted red flash which suggests that the enhanced responses in HD patients is specific to the cone photoreceptor pathway. Show more

Keywords: Cone photoreceptor, electroretinogram, Huntington’s disease, retina

DOI: 10.3233/JHD-170255

Citation: Journal of Huntington's Disease, vol. 6, no. 3, pp. 237-247, 2017