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1.
JAMA ; 322(17): 1682-1691, 2019 11 05.
Article in English | MEDLINE | ID: mdl-31688885

ABSTRACT

Importance: Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives: To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants: A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures: Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures: Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data. Results: A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-ß A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance: In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Black People/genetics , Genome-Wide Association Study , Glaucoma, Open-Angle/ethnology , Glaucoma, Open-Angle/genetics , Polymorphism, Single Nucleotide , Aged , Amyloid beta-Peptides/genetics , Case-Control Studies , Female , Genetic Predisposition to Disease , Genotype , Humans , Immunohistochemistry , Male , Meta-Analysis as Topic , Middle Aged , Risk Factors
2.
Am J Forensic Med Pathol ; 40(4): 371-375, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31306170

ABSTRACT

Creutzfeldt-Jakob disease (CJD) is a complex and rapidly fatal prion infection of the central nervous system with characteristic clinical and pathological findings. Herein, we present the case of an 80-year-old man with a 2-month history of rapid cognitive decline and ataxic gait. He was found to have a positive rapid plasma reagin and fluorescent treponemal antibody absorption (FTA-ABS) upon clinical testing and was presumed to have neurosyphilis. His neurological status precipitously declined during his hospitalization and he died. A complete autopsy was performed, which revealed diffuse spongiform change throughout the cerebrum. Brain tissue was sent to the National Prion Disease Surveillance Center, where immunostaining for prion protein (3F4) showed granular deposits, confirming the diagnosis of CJD. There have been rare cases reported in which CJD was clinically suspected but neurosyphilis was confirmed at autopsy. To our knowledge, this is the first case to be published in which the clinical findings strongly favored neurosyphilis, but spongiform encephalopathy was identified at autopsy. We review the clinical, radiographic, electrophysiological, laboratory, and histopathological features of both diseases and discuss the overlapping findings and inherent diagnostic difficulties. We also review the recommended protocols for safely handling suspected prion-infected autopsy tissue. A heightened awareness of the features of CJD and other prion diseases is needed among forensic pathologists, neuropathologists, and general autopsy pathologists to understand how to safely handle the tissue to get definite diagnoses for the decedent's family members and clinical care team.


Subject(s)
Brain/metabolism , Brain/pathology , Creutzfeldt-Jakob Syndrome/diagnosis , Prion Proteins/metabolism , Aged, 80 and over , Antibodies , Diagnosis, Differential , Humans , Male , Neurosyphilis/diagnosis , Prion Proteins/immunology
3.
J Neuropathol Exp Neurol ; 77(11): 1001-1004, 2018 11 01.
Article in English | MEDLINE | ID: mdl-30295806

ABSTRACT

Granulomatous amebic encephalitis is a rare necrotizing infection of the CNS that occurs most commonly in immunocompromised individuals and is usually fatal. It is difficult to diagnose as the clinical symptoms and radiographic findings are often mistaken for other bacterial, viral, fungal, or protozoan infections. Herein, we present the case of a 69-year-old heart transplant recipient who suffered fulminant neurological decline ∼5 months after transplant. Extensive radiographic and laboratory testing did not provide a definite anatomic diagnosis and, despite aggressive clinical treatment, he died. An autopsy examination demonstrated numerous brain abscesses which contained amebic trophozoites and cysts. An indirect immunofluorescence assay performed at the Centers for Disease Control confirmed the presence of Acanthamoeba species. To the best of our knowledge, only 13 other cases of Acanthamoeba amebic encephalitis have been reported in patients who have received solid organ transplants and this is the second case reported in a heart transplant recipient. This case emphasizes that amebic encephalitis should be in the differential diagnosis for immunocompromised patients with new brain lesions found on radiographic imaging.


Subject(s)
Acanthamoeba/pathogenicity , Central Nervous System Protozoal Infections/etiology , Heart Transplantation/adverse effects , Infectious Encephalitis/etiology , Aged , Autopsy , Central Nervous System Protozoal Infections/diagnostic imaging , Fatal Outcome , Humans , Infectious Encephalitis/diagnostic imaging , Magnetic Resonance Imaging , Male
4.
Brain ; 141(9): 2721-2739, 2018 09 01.
Article in English | MEDLINE | ID: mdl-30137212

ABSTRACT

Our hypothesis is that changes in gene and protein expression are crucial to the development of late-onset Alzheimer’s disease. Previously we examined how DNA alleles control downstream expression of RNA transcripts and how those relationships are changed in late-onset Alzheimer’s disease. We have now examined how proteins are incorporated into networks in two separate series and evaluated our outputs in two different cell lines. Our pipeline included the following steps: (i) predicting expression quantitative trait loci; (ii) determining differential expression; (iii) analysing networks of transcript and peptide relationships; and (iv) validating effects in two separate cell lines. We performed all our analysis in two separate brain series to validate effects. Our two series included 345 samples in the first set (177 controls, 168 cases; age range 65–105; 58% female; KRONOSII cohort) and 409 samples in the replicate set (153 controls, 141 cases, 115 mild cognitive impairment; age range 66–107; 63% female; RUSH cohort). Our top target is heat shock protein family A member 2 (HSPA2), which was identified as a key driver in our two datasets. HSPA2 was validated in two cell lines, with overexpression driving further elevation of amyloid-β40 and amyloid-β42 levels in APP mutant cells, as well as significant elevation of microtubule associated protein tau and phosphorylated-tau in a modified neuroglioma line. This work further demonstrates that studying changes in gene and protein expression is crucial to understanding late onset disease and further nominates HSPA2 as a specific key regulator of late-onset Alzheimer’s disease processes.10.1093/brain/awy215_video1awy215media15824729224001.


Subject(s)
Alzheimer Disease/genetics , Alzheimer Disease/physiopathology , HSP70 Heat-Shock Proteins/physiology , Aged , Aged, 80 and over , Alzheimer Disease/metabolism , Brain/metabolism , Brain Mapping/methods , Cell Line , Female , Gene Expression Profiling/methods , HEK293 Cells , HSP70 Heat-Shock Proteins/genetics , HSP70 Heat-Shock Proteins/metabolism , Humans , Male , Nerve Net/physiopathology , Protein Processing, Post-Translational , RNA/analysis , RNA/metabolism , Transcriptome/genetics
5.
Science ; 360(6395)2018 06 22.
Article in English | MEDLINE | ID: mdl-29930110

ABSTRACT

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.


Subject(s)
Brain Diseases/genetics , Mental Disorders/genetics , Brain Diseases/classification , Brain Diseases/diagnosis , Genetic Variation , Genome-Wide Association Study , Humans , Mental Disorders/classification , Mental Disorders/diagnosis , Phenotype , Quantitative Trait, Heritable , Risk Factors
6.
Article in English | MEDLINE | ID: mdl-28864461

ABSTRACT

Hemimegalencephaly (HME) is a heterogeneous cortical malformation characterized by enlargement of one cerebral hemisphere. Somatic variants in mammalian target of rapamycin (mTOR) regulatory genes have been implicated in some HME cases; however, ∼70% have no identified genetic etiology. Here, we screened two HME patients to identify disease-causing somatic variants. DNA from leukocytes, buccal swabs, and surgically resected brain tissue from two HME patients were screened for somatic variants using genome-wide genotyping arrays or sequencing of the protein-coding regions of the genome. Functional studies were performed to evaluate the molecular consequences of candidate disease-causing variants. Both HME patients evaluated were found to have likely disease-causing variants in DNA extracted from brain tissue but not in buccal swab or leukocyte DNA, consistent with a somatic mutational mechanism. In the first case, a previously identified disease-causing somatic single nucleotide in MTOR was identified. In the second case, we detected an overrepresentation of the alleles inherited from the mother on Chromosome 16 in brain tissue DNA only, indicative of somatic uniparental disomy (UPD) of the p-arm of Chromosome 16. Using methylation analyses, an imprinted locus on 16p spanning ZNF597 was identified, which results in increased expression of ZNF597 mRNA and protein in the brain tissue of the second case. Enhanced mTOR signaling was observed in tissue specimens from both patients. We speculate that overexpression of maternally expressed ZNF597 led to aberrant hemispheric development in the patient with somatic UPD of Chromosome 16p possibly through modulation of mTOR signaling.


Subject(s)
Hemimegalencephaly/genetics , Alleles , Brain/cytology , Child, Preschool , Chromosomes/genetics , Chromosomes, Human, Pair 16/genetics , DNA/genetics , DNA Methylation/genetics , Female , Genomic Imprinting , Genotype , Humans , Infant , Uniparental Disomy/genetics
7.
Acad Forensic Pathol ; 7(3): 494-501, 2017 Sep.
Article in English | MEDLINE | ID: mdl-31239998

ABSTRACT

Cerebral toxoplasmosis is an opportunistic infection of the central nervous system. Certain radiographic findings can be highly suggestive of the disease, but there is considerable overlap with both lymphoma and brain metastases, making the diagnosis difficult or delayed. Herein we present the case of a 77-year-old woman with a history of treated diffuse large B-cell lymphoma who presented with neurological symptoms four months after she was declared to be in remission. Her initial head computed tomography scan showed multiple low-attenuated lesions in her brain and a contrast enhanced magnetic resonance imaging scan showed multiple T1- and T2- enhancing lesions in the basal ganglia and at the gray-white junction. The clinical team was highly suspicious of a recurrence of her lymphoma so she had an extensive workup, including a brain biopsy, which did not lead to a definite diagnosis. After she died, an autopsy was performed, and multiple necrotic lesions were discovered in her brain. Histologic sections demonstrated numerous parasitic organisms, and immunohistochemical staining for Toxoplasma gondii was positive, confirming the diagnosis of cerebral toxoplasmosis. This case highlights an unusual case of cerebral toxoplasmosis that was diagnosed at autopsy and reviews the relevant radiographic findings as well as the gross and microscopic pathological features of the disease.

8.
Epilepsia ; 57(3): 376-85, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26799155

ABSTRACT

OBJECTIVE: Hippocampal sclerosis is the most common neuropathologic finding in cases of medically intractable mesial temporal lobe epilepsy. In this study, we analyzed the gene expression profiles of dentate granule cells of patients with mesial temporal lobe epilepsy with and without hippocampal sclerosis to show that next-generation sequencing methods can produce interpretable genomic data from RNA collected from small homogenous cell populations, and to shed light on the transcriptional changes associated with hippocampal sclerosis. METHODS: RNA was extracted, and complementary DNA (cDNA) was prepared and amplified from dentate granule cells that had been harvested by laser capture microdissection from surgically resected hippocampi from patients with mesial temporal lobe epilepsy with and without hippocampal sclerosis. Sequencing libraries were sequenced, and the resulting sequencing reads were aligned to the reference genome. Differential expression analysis was used to ascertain expression differences between patients with and without hippocampal sclerosis. RESULTS: Greater than 90% of the RNA-Seq reads aligned to the reference. There was high concordance between transcriptional profiles obtained for duplicate samples. Principal component analysis revealed that the presence or absence of hippocampal sclerosis was the main determinant of the variance within the data. Among the genes up-regulated in the hippocampal sclerosis samples, there was significant enrichment for genes involved in oxidative phosphorylation. SIGNIFICANCE: By analyzing the gene expression profiles of dentate granule cells from surgically resected hippocampal specimens from patients with mesial temporal lobe epilepsy with and without hippocampal sclerosis, we have demonstrated the utility of next-generation sequencing methods for producing biologically relevant results from small populations of homogeneous cells, and have provided insight on the transcriptional changes associated with this pathology.


Subject(s)
Dentate Gyrus/metabolism , Dentate Gyrus/pathology , Epilepsy, Temporal Lobe/diagnosis , Epilepsy, Temporal Lobe/metabolism , Principal Component Analysis/methods , Adult , Dentate Gyrus/surgery , Electroencephalography/methods , Epilepsy, Temporal Lobe/surgery , Female , Gene Expression Regulation , Hippocampus/metabolism , Hippocampus/pathology , Hippocampus/surgery , Humans , Male , Middle Aged , Sclerosis , Young Adult
9.
Hum Brain Mapp ; 36(8): 3167-78, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26043869

ABSTRACT

Deep brain stimulation (DBS) is an established surgical therapy for medically refractory tremor disorders including essential tremor (ET) and is currently under investigation for use in a variety of other neurologic and psychiatric disorders. There is growing evidence that the anti-tremor effects of DBS for ET are directly related to modulation of the dentatorubrothalamic tract (DRT), a white matter pathway that connects the cerebellum, red nucleus, and ventral intermediate nucleus of the thalamus. Emerging white matter targets for DBS, like the DRT, will require improved three-dimensional (3D) reference maps of deep brain anatomy and structural connectivity for accurate electrode targeting. High-resolution diffusion MRI of postmortem brain specimens can provide detailed volumetric images of important deep brain nuclei and 3D reconstructions of white matter pathways with probabilistic tractography techniques. We present a high spatial and angular resolution diffusion MRI template of the postmortem human brainstem and thalamus with 3D reconstructions of the nuclei and white matter tracts involved in ET circuitry. We demonstrate registration of these data to in vivo, clinical images from patients receiving DBS therapy, and correlate electrode proximity to tractography of the DRT with improvement of ET symptoms.


Subject(s)
Brain Stem/pathology , Brain Stem/surgery , Deep Brain Stimulation/methods , Diffusion Magnetic Resonance Imaging/methods , Implantable Neurostimulators , Thalamus/pathology , Thalamus/surgery , Aged , Essential Tremor/pathology , Essential Tremor/surgery , Female , Humans , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Male , Neural Pathways/pathology , Neural Pathways/surgery , White Matter/pathology , White Matter/surgery
11.
Acta Neuropathol ; 127(3): 407-18, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24442578

ABSTRACT

Hexanucleotide repeat expansions in chromosome 9 open reading frame 72 (C9orf72) have recently been linked to frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis, and may be the most common genetic cause of both neurodegenerative diseases. Genetic variants at TMEM106B influence risk for the most common neuropathological subtype of FTLD, characterized by inclusions of TAR DNA-binding protein of 43 kDa (FTLD-TDP). Previous reports have shown that TMEM106B is a genetic modifier of FTLD-TDP caused by progranulin (GRN) mutations, with the major (risk) allele of rs1990622 associating with earlier age at onset of disease. Here, we report that rs1990622 genotype affects age at death in a single-site discovery cohort of FTLD patients with C9orf72 expansions (n = 14), with the major allele correlated with later age at death (p = 0.024). We replicate this modifier effect in a 30-site international neuropathological cohort of FTLD-TDP patients with C9orf72 expansions (n = 75), again finding that the major allele associates with later age at death (p = 0.016), as well as later age at onset (p = 0.019). In contrast, TMEM106B genotype does not affect age at onset or death in 241 FTLD-TDP cases negative for GRN mutations or C9orf72 expansions. Thus, TMEM106B is a genetic modifier of FTLD with C9orf72 expansions. Intriguingly, the genotype that confers increased risk for developing FTLD-TDP (major, or T, allele of rs1990622) is associated with later age at onset and death in C9orf72 expansion carriers, providing an example of sign epistasis in human neurodegenerative disease.


Subject(s)
Frontotemporal Lobar Degeneration/genetics , Membrane Proteins/genetics , Nerve Tissue Proteins/genetics , Proteins/genetics , Adult , Age Factors , Age of Onset , Aged , Aged, 80 and over , Alleles , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/mortality , C9orf72 Protein , Cohort Studies , DNA Repeat Expansion , Female , Frontotemporal Lobar Degeneration/blood , Frontotemporal Lobar Degeneration/mortality , Genetic Predisposition to Disease , Genotype , Heterozygote , Humans , Intercellular Signaling Peptides and Proteins/blood , Male , Middle Aged , Polymorphism, Single Nucleotide , Progranulins
12.
J Neuropathol Exp Neurol ; 71(5): 362-81, 2012 May.
Article in English | MEDLINE | ID: mdl-22487856

ABSTRACT

Clinicopathologic correlation studies are critically important for the field of Alzheimer disease (AD) research. Studies on human subjects with autopsy confirmation entail numerous potential biases that affect both their general applicability and the validity of the correlations. Many sources of data variability can weaken the apparent correlation between cognitive status and AD neuropathologic changes. Indeed, most persons in advanced old age have significant non-AD brain lesions that may alter cognition independently of AD. Worldwide research efforts have evaluated thousands of human subjects to assess the causes of cognitive impairment in the elderly, and these studies have been interpreted in different ways. We review the literature focusing on the correlation of AD neuropathologic changes (i.e. ß-amyloid plaques and neurofibrillary tangles) with cognitive impairment. We discuss the various patterns of brain changes that have been observed in elderly individuals to provide a perspective for understanding AD clinicopathologic correlation and conclude that evidence from many independent research centers strongly supports the existence of a specific disease, as defined by the presence of Aß plaques and neurofibrillary tangles. Although Aß plaques may play a key role in AD pathogenesis, the severity of cognitive impairment correlates best with the burden of neocortical neurofibrillary tangles.


Subject(s)
Alzheimer Disease/complications , Alzheimer Disease/pathology , Brain/pathology , Cognition Disorders/etiology , Statistics as Topic , Aged , Aged, 80 and over , Amyloid beta-Peptides/metabolism , Brain/metabolism , Cognition Disorders/pathology , Humans , Neurofibrillary Tangles/pathology , Plaque, Amyloid/pathology
13.
Neurobiol Aging ; 33(7): 1485.e1-8, 2012 Jul.
Article in English | MEDLINE | ID: mdl-21185108

ABSTRACT

SORL1 has been identified as a major contributor to late onset Alzheimer's disease (LOAD). We test whether genetic variability in the 5' of SORL1 gene modulates the risk to develop LOAD via regulation of SORL1-messenger ribonucleic acid (mRNA) expression and splicing. Two brain structures, differentially vulnerable to LOAD pathology, were examined in 144 brain samples from 92 neurologically normal individuals. The temporal cortex, which is more susceptible to Alzheimer's pathology, demonstrated ∼2-fold increase in SORL1-mRNA levels in carriers of the minor alleles at single nucleotide polymorphisms (SNPs), rs7945931 and rs2298525, compared with noncarriers. No genetic effect on total-SORL1-mRNA levels was detected in the frontal cortex. However, rs11600875 minor allele was associated with significantly increased levels of exon-2 skipping, but only in frontal cortex. No correlation of SORL1-mRNAs expression was found between frontal and temporal cortexes. Collectively, these indicate the brain region specificity of the genetic regulation of SORL1 expression. Our results suggest that genetic regulation of SORL1 expression plays a role in disease risk and may be responsible for the reported LOAD associations. Further studies to detect the actual pathogenic variant/s are necessary.


Subject(s)
Alzheimer Disease/genetics , LDL-Receptor Related Proteins/genetics , Membrane Transport Proteins/genetics , Transcription, Genetic/physiology , Up-Regulation/physiology , Aged , Aged, 80 and over , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Female , Genetic Association Studies/methods , Humans , LDL-Receptor Related Proteins/biosynthesis , Male , Membrane Transport Proteins/biosynthesis , Middle Aged , Polymorphism, Single Nucleotide/genetics , Temporal Lobe/metabolism , Temporal Lobe/pathology
14.
J Neurosurg Spine ; 15(6): 625-9, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21888480

ABSTRACT

In this paper the authors describe the rare disorder of diffuse leptomeningeal oligodendrogliomatosis in a patient with an oligodendroglioma of the cauda equina who died suddenly. Reviewing this uncommon pathological entity is important so that it can be recognized and treated appropriately. This young, otherwise healthy woman with initial symptoms of low-back pain had a mass lesion of the cauda equina. During a workup, profound refractory intracranial hypertension suddenly developed despite aggressive surgical and medical intervention. Autopsy revealed a spinal cord oligodendroglioma with diffuse leptomeningeal oligodendrogliomatosis of the brain and spinal cord. Given the unforeseen outcome in this patient, this entity, although rare, should be considered in patients with similar presentations and addressed early to prevent similar outcomes. A review of the details of this case as well as the literature is presented below.


Subject(s)
Meningeal Neoplasms/pathology , Oligodendroglioma/pathology , Severity of Illness Index , Spinal Cord Neoplasms/pathology , Adult , Death, Sudden/pathology , Fatal Outcome , Female , Humans , Magnetic Resonance Imaging , Meningeal Neoplasms/surgery , Neoplasm Invasiveness/pathology , Oligodendroglioma/surgery , Spinal Cord Neoplasms/surgery , Tomography, X-Ray Computed
15.
Neurogenetics ; 12(1): 59-64, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21046180

ABSTRACT

Genetic variability at the 3' region of SNCA locus has been repeatedly associated with susceptibility to sporadic Parkinson's disease (PD). Accumulated evidence emphasizes the importance of SNCA dosage and expression levels in PD pathogenesis. However, the mechanism through which the 3' region of SNCA gene modulates the risk to develop sporadic PD remained elusive. We studied the effect of PD risk-associated variants at SNCA 3' regions on SNCA112-mRNA (exon 5 in-frame skipping) levels in vivo in 117 neuropathologically normal, human brain frontal cortex samples. SNPs tagging the SNCA 3' showed significant effects on the relative levels of SNCA112-mRNA from total SNCA transcripts levels. The "risk" alleles were correlated with increased expression ratio of SNCA112-mRNA from total. We provide evidence for functional consequences of PD-associated SNCA gene variants at the 3' region, suggesting that genetic regulation of SNCA splicing plays an important role in the development of the disease. Further studies to determine the definite functional variant/s within SNCA 3'and to establish their association with PD pathology are necessary.


Subject(s)
Alternative Splicing , Parkinson Disease/genetics , RNA Splice Sites , alpha-Synuclein/genetics , Exons , Frontal Lobe/metabolism , Genetic Predisposition to Disease , Genetic Variation , Humans , Linkage Disequilibrium , Parkinson Disease/etiology , Polymorphism, Single Nucleotide , RNA, Messenger/genetics
16.
Alzheimers Dement ; 7(3): 309-17, 2011 May.
Article in English | MEDLINE | ID: mdl-21075060

ABSTRACT

BACKGROUND: Metabolomics, the global science of biochemistry, provides powerful tools to map perturbations in the metabolic network and enables simultaneous quantification of several metabolites to identify metabolic perturbances that might provide insights into disease. METHODS: In this pilot study, we took a targeted electrochemistry-based metabolomics approach where liquid chromatography followed by coulometric array detection enables quantification of over 30 metabolites within key neurotransmitter pathways (dopamine and serotonin) and pathways involved in oxidative stress. RESULTS: Using samples from postmortem ventricular cerebrospinal fluid (15 Alzheimer's disease [AD] and 15 nondemented subjects with autopsy-confirmed diagnoses) and by using regression models, correlations, Wilcoxon rank-sum tests, and t-tests we identified alterations in tyrosine, tryptophan, purine, and tocopherol pathways in patients with AD. Reductions in norepinephrine and its related metabolites were also seen, consistent with previously published data. CONCLUSIONS: These data support further investigation of metabolomics in larger samples of clinical AD as well as in those with preclinical disease for use as biomarkers.


Subject(s)
Alzheimer Disease/diagnosis , Alzheimer Disease/metabolism , Metabolomics/methods , Aged , Aged, 80 and over , Alzheimer Disease/cerebrospinal fluid , Autopsy , Biogenic Amines/cerebrospinal fluid , Biomarkers/cerebrospinal fluid , Biomarkers/metabolism , Electrochemical Techniques/methods , Female , Humans , Male , Oxidative Stress/physiology , Pilot Projects , Predictive Value of Tests , Purines/cerebrospinal fluid , Tocopherols/cerebrospinal fluid
17.
Biochim Biophys Acta ; 1801(8): 951-9, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20488256

ABSTRACT

The neurosteroid allopregnanolone has pronounced neuroprotective actions, increases myelination, and enhances neurogenesis. Evidence suggests that allopregnanolone dysregulation may play a role in the pathophysiology of Alzheimer's disease (AD) and other neurodegenerative disorders. Our prior data demonstrate that allopregnanolone is reduced in prefrontal cortex in male patients with AD compared to male cognitively intact control subjects, and inversely correlated with neuropathological disease stage (Braak and Braak). We therefore determined if allopregnanolone levels are also reduced in AD patients compared to control subjects in temporal cortex, utilizing a larger set of samples from both male and female patients. In addition, we investigated if neurosteroids are altered in subjects who are APOE4 allele carriers. Allopregnanolone, dehydroepiandrosterone (DHEA), and pregnenolone levels were determined in temporal cortex postmortem samples by gas chromatography/mass spectrometry, preceded by high performance liquid chromatography (40 subjects with AD/41 cognitively intact control subjects). Allopregnanolone levels are reduced in temporal cortex in patients with AD (median 2.68 ng/g, n=40) compared to control subjects (median 5.64 ng/g, n=41), Mann-Whitney p=0.0002, and inversely correlated with Braak and Braak neuropathological disease stage (Spearman r=-0.38, p=0.0004). DHEA and pregnenolone are increased in patients with AD compared to control subjects. Patients carrying an APOE4 allele demonstrate reduced allopregnanolone levels in temporal cortex (Mann-Whitney p=0.04). In summary, our findings indicate that neurosteroids are altered in temporal cortex in patients with AD and related to neuropathological disease stage. In addition, the APOE4 allele is associated with reduced allopregnanolone levels. Neurosteroids may be relevant to the neurobiology and therapeutics of AD.


Subject(s)
Alzheimer Disease/pathology , Pregnanolone/analysis , Temporal Lobe/chemistry , Adult , Aged , Aged, 80 and over , Alleles , Alzheimer Disease/genetics , Alzheimer Disease/metabolism , Apolipoprotein E4/genetics , Case-Control Studies , Cerebral Cortex/chemistry , Cerebral Cortex/metabolism , Chromatography, High Pressure Liquid , Cognition/physiology , Female , Gas Chromatography-Mass Spectrometry , Humans , Male , Middle Aged , Models, Biological , Postmortem Changes , Pregnanolone/metabolism , Temporal Lobe/metabolism
18.
Nat Genet ; 42(3): 234-9, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20154673

ABSTRACT

Frontotemporal lobar degeneration (FTLD) is the second most common cause of presenile dementia. The predominant neuropathology is FTLD with TAR DNA-binding protein (TDP-43) inclusions (FTLD-TDP). FTLD-TDP is frequently familial, resulting from mutations in GRN (which encodes progranulin). We assembled an international collaboration to identify susceptibility loci for FTLD-TDP through a genome-wide association study of 515 individuals with FTLD-TDP. We found that FTLD-TDP associates with multiple SNPs mapping to a single linkage disequilibrium block on 7p21 that contains TMEM106B. Three SNPs retained genome-wide significance following Bonferroni correction (top SNP rs1990622, P = 1.08 x 10(-11); odds ratio, minor allele (C) 0.61, 95% CI 0.53-0.71). The association replicated in 89 FTLD-TDP cases (rs1990622; P = 2 x 10(-4)). TMEM106B variants may confer risk of FTLD-TDP by increasing TMEM106B expression. TMEM106B variants also contribute to genetic risk for FTLD-TDP in individuals with mutations in GRN. Our data implicate variants in TMEM106B as a strong risk factor for FTLD-TDP, suggesting an underlying pathogenic mechanism.


Subject(s)
Chromosomes, Human, Pair 7 , DNA-Binding Proteins/metabolism , Frontotemporal Lobar Degeneration/genetics , Inclusion Bodies/metabolism , Polymorphism, Single Nucleotide , Case-Control Studies , Frontotemporal Lobar Degeneration/metabolism , Gene Frequency , Genetic Predisposition to Disease , Genome-Wide Association Study , Genotype , Humans , Inclusion Bodies/genetics , Intercellular Signaling Peptides and Proteins/genetics , Linkage Disequilibrium , Membrane Proteins/genetics , Progranulins
19.
J Alzheimers Dis ; 19(1): 69-77, 2010.
Article in English | MEDLINE | ID: mdl-20061627

ABSTRACT

Alzheimer's disease is a complex and progressive neurodegenerative disease leading to loss of memory, cognitive impairment, and ultimately death. To date, six large-scale genome-wide association studies have been conducted to identify SNPs that influence disease predisposition. These studies have confirmed the well-known APOE epsilon4 risk allele, identified a novel variant that influences disease risk within the APOE epsilon4 population, found a SNP that modifies the age of disease onset, as well as reported the first sex-linked susceptibility variant. Here we report a genome-wide scan of Alzheimer's disease in a set of 331 cases and 368 controls, extending analyses for the first time to include assessments of copy number variation. In this analysis, no new SNPs show genome-wide significance. We also screened for effects of copy number variation, and while nothing was significant, a duplication in CHRNA7 appears interesting enough to warrant further investigation.


Subject(s)
Alzheimer Disease/genetics , DNA Copy Number Variations/genetics , Genetic Variation/genetics , Genome-Wide Association Study , Adult , Aged , Aged, 80 and over , Alzheimer Disease/pathology , Apolipoprotein E4/genetics , Female , Genetic Predisposition to Disease , Genome-Wide Association Study/methods , Humans , Male , Middle Aged , Polymorphism, Single Nucleotide , Young Adult
20.
Neurobiol Aging ; 31(4): 549-66, 2010 Apr.
Article in English | MEDLINE | ID: mdl-18572275

ABSTRACT

While the clinical and neuropathological characterization of Alzheimer's Disease (AD) is well defined, our understanding of the progression of pathologic mechanisms in AD remains unclear. Post-mortem brains from individuals who did not fulfill clinical criteria for AD may still demonstrate measurable levels of AD pathologies to suggest that they may have presented with clinical symptoms had they lived longer or are able to stave off disease progression. Comparison between such individuals and those clinically diagnosed and pathologically confirmed to have AD will be key in delineating AD pathogenesis and neuroprotection. In this study, we expression profiled laser capture microdissected non-tangle bearing neurons in 6 post-mortem brain regions that are differentially affected in the AD brain from 10 non-demented individuals demonstrating intermediate AD neuropathologies (NDAD; Braak stage of II through IV and CERAD rating of moderate to frequent) and evaluated this data against that from individuals who have been diagnosed with late onset AD as well as healthy elderly controls. We identified common statistically significant expression changes in both NDAD and AD brains that may establish a degenerative link between the two cohorts, in addition to NDAD specific transcriptomic changes. These findings pinpoint novel targets for developing earlier diagnostics and preventative therapies for AD prior to diagnosis of probable AD. We also provide this high-quality, low post-mortem interval (PMI), cell-specific, and region-specific NDAD/AD reference data set to the community as a public resource.


Subject(s)
Alzheimer Disease/genetics , Alzheimer Disease/pathology , Brain/pathology , Gene Expression Profiling/methods , Gene Expression Regulation/physiology , Neurons/pathology , Aged, 80 and over , Alzheimer Disease/physiopathology , Brain/metabolism , Brain/physiopathology , Cohort Studies , Databases, Genetic , Disease Progression , Female , Humans , Male , Microdissection/methods , Nerve Tissue Proteins/genetics , Neurons/metabolism , Oligonucleotide Array Sequence Analysis , Plaque, Amyloid/genetics , Plaque, Amyloid/metabolism , Predictive Value of Tests , Proteasome Endopeptidase Complex/genetics , Proteasome Endopeptidase Complex/metabolism , RNA, Messenger/analysis , RNA, Messenger/metabolism , Reference Standards , Reverse Transcriptase Polymerase Chain Reaction , Synapses/metabolism , Synapses/pathology
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