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1.
Intern Med J ; 54(3): 503-510, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38251817

ABSTRACT

The Australian Commission of Safety and Quality in Health Care mandates the application of the eight National Safety and Quality Health Service Standards to minimise high-risk adverse events in hospital settings for all Australian patients. It acknowledges that adults with intellectual disability require reasonable adjustments to the application of the standards to optimise the impact of the quality and safety measures for this group. The paper proposes a system whereby reasonable adjustments can be developed for this population. First, particular criteria, items or actions of a standard are selected for the formulation of reasonable adjustments. Second, the adjustments are broken down into categories of alterations to usual knowledge, process, content and organisation involved in compliance with the chosen aspect of the standard. Third, the categories of reasonable adjustments are simultaneously influenced and shaped by aspects of living with intellectual disability, disability supports and a health-disability sectoral interface.


Subject(s)
Intellectual Disability , Adult , Humans , Intellectual Disability/epidemiology , Australia/epidemiology , Hospitals , Patients , Health Services
2.
MicroPubl Biol ; 20232023.
Article in English | MEDLINE | ID: mdl-37008727

ABSTRACT

Mutations in TDP-43 are known to cause Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). TDP-43 binds to and regulates splicing of several RNA including Zmynd11 . Zmynd11 is a transcriptional repressor and a potential E3 ubiquitin ligase family member, known for its role in neuron and muscle differentiation. Mutations in Zmynd11 have been associated with autism with significant developmental motor delays, intellectual disability, and ataxia. Here, we show that Zmynd11 is aberrantly spliced in the brain and spinal cord of transgenic mice overexpressing a mutant human TDP-43 (A315T), and that these changes occur before the onset of motor symptoms.

3.
Intern Med J ; 51(11): 1963-1968, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34796628

ABSTRACT

Contemporary disability principles and values suggest that adults with intellectual disability should be able to access and participate in any mainstream service rather than having a separate service for them. In the case of healthcare services, achievement of optimal access to and participation in healthcare by adults with intellectual disability requires the presence of both adequate disability supports for the person and reasonable adjustments to generic health systems to enable a person-centred approach to care. Development of an interface between people with lived experience of intellectual disability, disability and health sectors help clarify the required nature of disability supports and types of adjustments to mainstream health services. The article describes a case study of an adult with intellectual disability with a serious illness warranting palliative care, and focusses on the reasonable adjustments to mainstream core palliative care principles for adults with intellectual disability.


Subject(s)
Intellectual Disability , Palliative Care , Adult , Delivery of Health Care , Humans , Intellectual Disability/therapy
4.
BMC Mol Cell Biol ; 21(1): 26, 2020 Apr 15.
Article in English | MEDLINE | ID: mdl-32293262

ABSTRACT

BACKGROUND: Progesterone receptor membrane component 1 (PGRMC1) is often elevated in cancers, and exists in alternative states of phosphorylation. A motif centered on PGRMC1 Y180 was evolutionarily acquired concurrently with the embryological gastrulation organizer that orchestrates vertebrate tissue differentiation. RESULTS: Here, we show that mutagenic manipulation of PGRMC1 phosphorylation alters cell metabolism, genomic stability, and CpG methylation. Each of several mutants elicited distinct patterns of genomic CpG methylation. Mutation of S57A/Y180/S181A led to increased net hypermethylation, reminiscent of embryonic stem cells. Pathways enrichment analysis suggested modulation of processes related to animal cell differentiation status and tissue identity, as well as cell cycle control and ATM/ATR DNA damage repair regulation. We detected different genomic mutation rates in culture. CONCLUSIONS: A companion manuscript shows that these cell states dramatically affect protein abundances, cell and mitochondrial morphology, and glycolytic metabolism. We propose that PGRMC1 phosphorylation status modulates cellular plasticity mechanisms relevant to early embryological tissue differentiation.


Subject(s)
Phosphorylation , Receptors, Progesterone , Animals , Cell Differentiation , Cell Line , DNA Methylation , Disease , Embryology , Epigenomics , Humans , Membrane Proteins/biosynthesis , Membrane Proteins/metabolism , Mice , Mutation , Mutation Rate , Protein Processing, Post-Translational , Receptors, Progesterone/biosynthesis , Receptors, Progesterone/metabolism
5.
Intern Med J ; 48(3): 351-359, 2018 03.
Article in English | MEDLINE | ID: mdl-29512328

ABSTRACT

Preventable poor health outcomes for adults with intellectual disability in health settings have been known about for years. Subsequent analysis and the sorts of reasonable adjustments required in health and disability support settings to address these health gaps are well described, but have not really been embedded in practice in any significant way in either setting. As far as health is concerned, implementation of the National Disability Insurance Scheme (NDIS, the Scheme) affords an opportunity to recognise individual needs of people with intellectual disability to provide reasonable and necessary functional support for access to mainstream health services, to build capacity of mainstream health providers to supply services and to increase individual capacity to access services. Together these strands have potential to transform health outcomes. Success of the Scheme, however, rests on as yet incompletely defined operational interaction between NDIS and mainstream health services and inherently involves the disability sector. This interaction is especially relevant for adults with intellectual disability, known high users of hospitals and for whom hospital outcomes are particularly poor and preventable. Keys to better hospital outcomes are first, the receiving of quality person-centred healthcare from physicians and hospitals taking into account significance of intellectual disability and second, formulation of organised quality functional supports during hospitalisation. Achieving these require sophisticated engagement between consumers, the National Disability Insurance Agency, Commonwealth, State and Territory government leaders, senior hospital and disability administrators, NDIS service providers and clinicians and involves cross fertilisation of values, sharing of operational policies and procedures, determination of boundaries of fiscal responsibility for functional supports in hospital.


Subject(s)
Health Status , Hospitals/trends , Insurance, Disability/trends , Intellectual Disability/epidemiology , Intellectual Disability/therapy , Activities of Daily Living , Adult , Australia/epidemiology , Hospitalization/economics , Hospitalization/trends , Humans , Insurance, Disability/economics , Intellectual Disability/economics , Quality of Health Care/economics , Quality of Health Care/trends
6.
Genome Med ; 9(1): 97, 2017 Nov 17.
Article in English | MEDLINE | ID: mdl-29149916

ABSTRACT

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease characterised by the degeneration of motor neurons, which are responsible for voluntary movement. There remains limited understanding of disease aetiology, with median survival of ALS of three years and no effective treatment. Identifying genes that contribute to ALS susceptibility is an important step towards understanding aetiology. The vast majority of published human genetic studies, including for ALS, have used samples of European ancestry. The importance of trans-ethnic studies in human genetic studies is widely recognised, yet a dearth of studies of non-European ancestries remains. Here, we report analyses of novel whole-exome sequencing (WES) data from Chinese ALS and control individuals. METHODS: WES data were generated for 610 ALS cases and 460 controls drawn from Chinese populations. We assessed evidence for an excess of rare damaging mutations at the gene level and the gene set level, considering only singleton variants filtered to have allele frequency less than 5 × 10-5 in reference databases. To meta-analyse our results with a published study of European ancestry, we used a Cochran-Mantel-Haenszel test to compare gene-level variant counts in cases vs controls. RESULTS: No gene passed the genome-wide significance threshold with ALS in Chinese samples alone. Combining rare variant counts in Chinese with those from the largest WES study of European ancestry resulted in three genes surpassing genome-wide significance: TBK1 (p = 8.3 × 10-12), SOD1 (p = 8.9 × 10-9) and NEK1 (p = 1.1 × 10-9). In the Chinese data alone, SOD1 and NEK1 were nominally significantly associated with ALS (p = 0.04 and p = 7 × 10-3, respectively) and the case/control frequencies of rare coding variants in these genes were similar in Chinese and Europeans (SOD1: 1.5%/0.2% vs 0.9%/0.1%, NEK1 1.8%/0.4% vs 1.9%/0.8%). This was also true for TBK1 (1.2%/0.2% vs 1.4%/0.4%), but the association with ALS in Chinese was not significant (p = 0.14). CONCLUSIONS: While SOD1 is already recognised as an ALS-associated gene in Chinese, we provide novel evidence for association of NEK1 with ALS in Chinese, reporting variants in these genes not previously found in Europeans.


Subject(s)
Amyotrophic Lateral Sclerosis/genetics , NIMA-Related Kinase 1/genetics , Asian People/genetics , Genetic Predisposition to Disease , Humans , Risk , Exome Sequencing
7.
Nat Commun ; 8(1): 611, 2017 09 20.
Article in English | MEDLINE | ID: mdl-28931804

ABSTRACT

Cross-ethnic genetic studies can leverage power from differences in disease epidemiology and population-specific genetic architecture. In particular, the differences in linkage disequilibrium and allele frequency patterns across ethnic groups may increase gene-mapping resolution. Here we use cross-ethnic genetic data in sporadic amyotrophic lateral sclerosis (ALS), an adult-onset, rapidly progressing neurodegenerative disease. We report analyses of novel genome-wide association study data of 1,234 ALS cases and 2,850 controls. We find a significant association of rs10463311 spanning GPX3-TNIP1 with ALS (p = 1.3 × 10-8), with replication support from two independent Australian samples (combined 576 cases and 683 controls, p = 1.7 × 10-3). Both GPX3 and TNIP1 interact with other known ALS genes (SOD1 and OPTN, respectively). In addition, GGNBP2 was identified using gene-based analysis and summary statistics-based Mendelian randomization analysis, although further replication is needed to confirm this result. Our results increase our understanding of genetic aetiology of ALS.Amyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disease. Here, Wray and colleagues identify association of the GPX3-TNIP1 locus with ALS using cross-ethnic meta-analyses.


Subject(s)
Amyotrophic Lateral Sclerosis/genetics , Asian People/genetics , DNA-Binding Proteins/genetics , Glutathione Peroxidase/genetics , White People/genetics , Amyotrophic Lateral Sclerosis/ethnology , Australia , China , Genome-Wide Association Study , High-Throughput Nucleotide Sequencing , Humans , Sequence Analysis, DNA
8.
Prev Chronic Dis ; 13: E91, 2016 07 14.
Article in English | MEDLINE | ID: mdl-27418213

ABSTRACT

Public health researchers have used a class of statistical methods to calculate prevalence estimates for small geographic areas with few direct observations. Many researchers have used Behavioral Risk Factor Surveillance System (BRFSS) data as a basis for their models. The aims of this study were to 1) describe a new BRFSS small area estimation (SAE) method and 2) investigate the internal and external validity of the BRFSS SAEs it produced. The BRFSS SAE method uses 4 data sets (the BRFSS, the American Community Survey Public Use Microdata Sample, Nielsen Claritas population totals, and the Missouri Census Geographic Equivalency File) to build a single weighted data set. Our findings indicate that internal and external validity tests were successful across many estimates. The BRFSS SAE method is one of several methods that can be used to produce reliable prevalence estimates in small geographic areas.


Subject(s)
Behavioral Risk Factor Surveillance System , Population Surveillance/methods , Prevalence , Public Health/statistics & numerical data , Humans , Public Health/standards , Reproducibility of Results , Small-Area Analysis , United States
9.
Neurology ; 86(8): 713-22, 2016 Feb 23.
Article in English | MEDLINE | ID: mdl-26802095

ABSTRACT

OBJECTIVE: To analyze the clinical syndromes and inheritance patterns of multiplex families with epilepsy toward the ultimate aim of uncovering the underlying molecular genetic basis. METHODS: Following the referral of families with 2 or more relatives with epilepsy, individuals were classified into epilepsy syndromes. Families were classified into syndromes where at least 2 family members had a specific diagnosis. Pedigrees were analyzed and molecular genetic studies were performed as appropriate. RESULTS: A total of 211 families were ascertained over an 11-year period in Israel. A total of 169 were classified into broad familial epilepsy syndrome groups: 61 generalized, 22 focal, 24 febrile seizure syndromes, 33 special syndromes, and 29 mixed. A total of 42 families remained unclassified. Pathogenic variants were identified in 49/211 families (23%). The majority were found in established epilepsy genes (e.g., SCN1A, KCNQ2, CSTB), but in 11 families, this cohort contributed to the initial discovery (e.g., KCNT1, PCDH19, TBC1D24). We expand the phenotypic spectrum of established epilepsy genes by reporting a familial LAMC3 homozygous variant, where the predominant phenotype was epilepsy with myoclonic-atonic seizures, and a pathogenic SCN1A variant in a family where in 5 siblings the phenotype was broadly consistent with Dravet syndrome, a disorder that usually occurs sporadically. CONCLUSION: A total of 80% of families were successfully classified, with pathogenic variants identified in 23%. The successful characterization of familial electroclinical and inheritance patterns has highlighted the value of studying multiplex families and their contribution towards uncovering the genetic basis of the epilepsies.


Subject(s)
Epilepsy/epidemiology , Epilepsy/genetics , Family , Genetic Predisposition to Disease/epidemiology , Genetic Predisposition to Disease/genetics , Genetic Testing/methods , Cohort Studies , Epilepsy/diagnosis , Female , Humans , Israel/epidemiology , Male , Pedigree
10.
PLoS One ; 8(11): e81170, 2013.
Article in English | MEDLINE | ID: mdl-24312274

ABSTRACT

In amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration, TAR DNA binding protein 43 (TDP-43) accumulates in the cytoplasm of affected neurons and glia, where it associates with stress granules (SGs) and forms large inclusions. SGs form in response to cellular stress, including endoplasmic reticulum (ER) stress, which is induced in both familial and sporadic forms of ALS. Here we demonstrate that pharmacological induction of ER stress causes TDP-43 to accumulate in the cytoplasm, where TDP-43 also associates with SGs. Furthermore, treatment with salubrinal, an inhibitor of dephosphorylation of eukaryotic initiation factor 2-α, a key modulator of ER stress, potentiates ER stress-mediated SG formation. Inclusions of C-terminal fragment TDP-43, reminiscent of disease-pathology, form in close association with ER and Golgi compartments, further indicating the involvement of ER dysfunction in TDP-43-associated disease. Consistent with this notion, over-expression of ALS-linked mutant TDP-43, and to a lesser extent wildtype TDP-43, triggers several ER stress pathways in neuroblastoma cells. Similarly, we found an interaction between the ER chaperone protein disulphide isomerase and TDP-43 in transfected cell lysates and in the spinal cords of mutant A315T TDP-43 transgenic mice. This study provides evidence for ER stress as a pathogenic pathway in TDP-43-mediated disease.


Subject(s)
Amyotrophic Lateral Sclerosis/metabolism , Amyotrophic Lateral Sclerosis/pathology , Cytoplasm/metabolism , DNA-Binding Proteins/metabolism , Endoplasmic Reticulum Stress , Active Transport, Cell Nucleus/drug effects , Amyotrophic Lateral Sclerosis/genetics , Animals , Cell Line , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Cinnamates/pharmacology , Cytoplasm/drug effects , DNA-Binding Proteins/genetics , Endoplasmic Reticulum Stress/drug effects , Golgi Apparatus/drug effects , Golgi Apparatus/metabolism , Humans , Mice , Mutation , Protein Disulfide-Isomerases/metabolism , Spinal Cord/metabolism , Thiourea/analogs & derivatives , Thiourea/pharmacology
11.
PLoS One ; 8(4): e60274, 2013.
Article in English | MEDLINE | ID: mdl-23593184

ABSTRACT

BACKGROUND: The Coloboma mouse carries a ∼2 cM deletion encompassing the SNAP25 gene and has a hyperactive phenotype similar to that of ADHD. Such mice are 3 fold more active compared to their control littermates. Genetic association studies support a role for allelic variants of the human SNAP25 gene in predisposing to ADHD. METHODS/PRINCIPAL FINDINGS: We performed association analysis across the SNAP25 gene in 1,107 individuals (339 ADHD trios). To assess the functional relevance of the SNAP25-ADHD associated allele, we performed quantitative PCR on post-mortem tissue derived from the inferior frontal gyrus of 89 unaffected adults. Significant associations with the A allele of SNP rs362990 (χ(2) = 10, p-corrected = 0.019, OR = 1.5) and three marker haplotypes (rs6108461, rs362990 and rs362998) were observed. Furthermore, a significant additive decrease in the expression of the SNAP25 transcript as a function of the risk allele was also observed. This effect was detected at the haplotype level, where increasing copies of the ADHD-associated haplotype reduced the expression of the transcript. CONCLUSIONS: Our data show that DNA variation at SNAP25 confers risk to ADHD and reduces the expression of the transcript in a region of the brain that is critical for the regulation of attention and inhibition.


Subject(s)
DNA/genetics , Genetic Predisposition to Disease , Polymorphism, Single Nucleotide/genetics , Prefrontal Cortex/metabolism , Synaptosomal-Associated Protein 25/genetics , Adult , Animals , Attention Deficit Disorder with Hyperactivity/genetics , Child , Genetic Association Studies , Haplotypes/genetics , Humans , Linkage Disequilibrium/genetics , Male , Mice , Prefrontal Cortex/pathology , Risk Factors , Synaptosomal-Associated Protein 25/metabolism
12.
Psychopharmacology (Berl) ; 225(4): 895-902, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23052569

ABSTRACT

Pharmacological evidence suggests the importance of noradrenergic and other monoaminergic neurotransmitters in the aetiology and treatment of attention deficit hyperactivity disorder (ADHD). Until recently, the genes of the noradrenergic pathway were not intensively investigated in ADHD compared to dopaminergic and serotonergic candidates. In this study, 91 SNP markers of 14 noradrenergic genes (an average density of one SNP per 4.5 kbp) were examined in ADHD samples from Ireland and Australia. Although suggestive evidence of association (nominal p ≤ 0.05) with the genes SLC6A2, ADRA1A, ADRA1B and ADRA2B was observed, none remained significant after permutation adjustments. In contrast, haplotype analyses demonstrated a significant association between ADHD and a SLC6A2 haplotype comprising the markers rs36009, rs1800887, rs8049681, rs2242447 and rs9930182 (χ(2) = 9.39, p-corrected = 0.019, OR = 1.51). A rare ADRA1B haplotype made of six SNPs (rs2030373, rs6884105, rs756275, rs6892282, rs6888306 and rs13162302) was also associated (χ(2) = 7.79, p-corrected = 0.042 OR = 2.74) with the disorder. These findings provide evidence of a contribution of the noradrenaline system to the genetic aetiology of ADHD. The observed haplotype association signals may be driven by as yet unidentified functional risk variants in or around the associated regions. Functional genomic analysis is warranted to determine the biological mechanism of the observed association.


Subject(s)
Attention Deficit Disorder with Hyperactivity/genetics , Chromosome Mapping/methods , Genetic Association Studies/methods , Linkage Disequilibrium/genetics , Norepinephrine Plasma Membrane Transport Proteins/genetics , Receptors, Adrenergic, alpha-1/genetics , Adolescent , Attention Deficit Disorder with Hyperactivity/diagnosis , Attention Deficit Disorder with Hyperactivity/epidemiology , Child , Female , Humans , Male , Polymorphism, Single Nucleotide/genetics , Receptors, Adrenergic/genetics
13.
Article in English | MEDLINE | ID: mdl-23134510

ABSTRACT

Cytoplasmic inclusions containing TDP-43 are a pathological hallmark of several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. TDP-43 is an RNA binding protein involved in gene regulation through control of RNA transcription, splicing and transport. However, the function of TDP-43 in the nervous system is largely unknown and its role in the pathogenesis of ALS is unclear. The aim of this study was to identify genes in the central nervous system that are regulated by TDP-43. RNA-immunoprecipitation with anti-TDP-43 antibody, followed by microarray analysis (RIP-chip), was used to isolate and identify RNA bound to TDP-43 protein from mouse brain. This analysis produced a list of 1839 potential TDP-43 gene targets, many of which overlap with previous studies and whose functions include RNA processing and synaptic function. Immunohistochemistry demonstrated that the TDP-43 protein could be found at the presynaptic membrane of axon terminals in the neuromuscular junction in mice. In conclusion, the finding that TDP-43 binds to RNA that codes for genes related to synaptic function, together with the localization of TDP-43 protein at axon terminals, suggests a role for TDP-43 in the transport of synaptic mRNAs into distal processes.


Subject(s)
Brain/metabolism , DNA-Binding Proteins/metabolism , Presynaptic Terminals/metabolism , RNA/metabolism , Ribonucleoproteins/metabolism , Animals , DNA-Binding Proteins/analysis , Mice , Mice, Inbred C57BL , Presynaptic Terminals/chemistry , Protein Binding/physiology , RNA/analysis , Ribonucleoproteins/analysis
14.
Behav Brain Funct ; 8: 25, 2012 May 28.
Article in English | MEDLINE | ID: mdl-22640745

ABSTRACT

BACKGROUND: This study explored the association between three measures of working memory ability and genetic variation in a range of catecholamine genes in a sample of children with ADHD. METHODS: One hundred and eighteen children with ADHD performed three working memory measures taken from the CANTAB battery (Spatial Span, Delayed-match-to-sample, and Spatial Working Memory). Associations between performance on working memory measures and allelic variation in catecholamine genes (including those for the noradrenaline transporter [NET1], the dopamine D4 and D2 receptor genes [DRD4; DRD2], the gene encoding dopamine beta hydroxylase [DBH] and catechol-O-methyl transferase [COMT]) were investigated using regression models that controlled for age, IQ, gender and medication status on the day of test. RESULTS: Significant associations were found between performance on the delayed-match-to-sample task and COMT genotype. More specifically, val/val homozygotes produced significantly more errors than did children who carried a least one met allele. There were no further associations between allelic variants and performance across the other working memory tasks. CONCLUSIONS: The working memory measures employed in the present study differed in the degree to which accurate task performance depended upon either the dynamic updating and/or manipulation of items in working memory, as in the spatial span and spatial working memory tasks, or upon the stable maintenance of representations, as in the delay-match-to-sample task. The results are interpreted as evidence of a relationship between tonic dopamine levels associated with the met COMT allele and the maintenance of stable working memory representations required to perform the delayed-match-to-sample-task.


Subject(s)
Attention Deficit Disorder with Hyperactivity/genetics , Catechol O-Methyltransferase/genetics , Genetic Variation/genetics , Memory, Short-Term/physiology , Adolescent , Alleles , Child , Female , Genotype , Heterozygote , Homozygote , Humans , Male , Neuropsychological Tests , Pattern Recognition, Visual/physiology , Phenotype , Reaction Time/genetics , Valine/genetics
16.
Neuroimage ; 58(1): 69-74, 2011 Sep 01.
Article in English | MEDLINE | ID: mdl-21689764

ABSTRACT

Amyotrophic lateral sclerosis (ALS) is characterized by selective degeneration of motor neurons. Current imaging studies have concentrated on areas of the brain and spinal cord that contain mixed populations of sensory and motor neurons. In this study, ex vivo magnetic resonance microimaging (MRM) was used to separate motor and sensory components by visualizing individual dorsal and ventral roots in fixed spinal cords. MRM at 15µm in plane resolution enabled the axons of pure populations of sensory and motor neurons to be measured in the lumbar region of the SOD1 mouse model of ALS. MRM signal intensity increased by 38.3% (p<0.05) exclusively in the ventral motor nerve roots of the lumbar spinal cord of ALS-affected SOD1 mice compared to wildtype littermates. The hyperintensity was therefore limited to white matter tracts arising from the motor neurons, whereas sensory white matter fibers were unchanged. Significant decreases in ventral nerve root volume were also detected in the SOD1 mice, which correlated with the axonal degeneration observed by microscopy. These results demonstrate the usefulness of MRM in visualizing the ultrastructure of the mouse spinal cord. The detailed 3D anatomy allowed the processes of pure populations of sensory and motor neurons to be compared.


Subject(s)
Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/pathology , Motor Neurons/pathology , Nerve Degeneration/pathology , Spinal Cord/pathology , Spinal Nerve Roots/pathology , Superoxide Dismutase/genetics , Animals , Cell Count , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Mice , Mice, Inbred C57BL , Mice, Transgenic , Superoxide Dismutase-1
17.
Alzheimers Res Ther ; 3(2): 13, 2011 Apr 19.
Article in English | MEDLINE | ID: mdl-21542885

ABSTRACT

The clinical and scientific study of dementia in adults with Down syndrome led to the development of the amyloid hypothesis as a fundamental concept in Alzheimer's disease pathogenesis. The journey started with the discovery of the structure and metabolic processing of ß-amyloid brain deposits associated with Alzheimer's dementia in adults with Down syndrome, and then the prediction and confirmation of the amyloid precursor protein gene on chromosome 21. The processes and genes responsible for tau hyperphosphorylation contributing to toxic brain deposits were additionally identified. With increasing sophistication in genetic experimental techniques, additional mechanisms associated with excessive amyloid deposits were postulated and tested in brains of people with Down syndrome and Alzheimer's disease and in those with early-onset Alzheimer's disease. This in turn led to the proposal and testing for particular genetic defects associated with familial early-onset Alzheimer's disease. Nearly 200 genetic causes of early-onset types of Alzheimer's disease have since been identified. Only a minority of these causes are on chromosome 21, although the aetiology of excess amyloid production remains fundamental to their pathogenesis. Knowledge of the pathogenic mechanisms of Alzheimer's disease in predisposed families and in people with Down syndrome is a step closer to prevention or cure of this devastating disease.

18.
Neuroimage ; 55(2): 455-61, 2011 Mar 15.
Article in English | MEDLINE | ID: mdl-21185943

ABSTRACT

Amyotrophic lateral sclerosis (ALS) is characterized by selective degeneration of motor neurons. Here we examine the ability of magnetic resonance imaging (MRI) to measure axonal degeneration in the lumbar spinal cord of the SOD1 mouse model of ALS. Diffusion tensor imaging (DTI) was successful in detecting axonal spinal cord damage in vivo. Fractional anisotropy (FA) values were reduced exclusively in the ventral white matter tracts of the lumbar spinal cord of ALS-affected SOD1 mice compared to wild-type littermates, with this effect becoming more pronounced with disease progression. The reduced FA values were therefore limited to white matter tracts arising from the motor neurons, whereas sensory white matter fibers were preserved. Significant decreases in water diffusion parallel to the white matter fibers or axial diffusivity were observed in the SOD1 mice, which can be attributed to the axonal degeneration observed by electron microscopy. At the same time, radial diffusivity perpendicular to the spinal column increased in the SOD1 mice, reflecting reduced myelination. These results demonstrate the usefulness of MRI in tracking disease progression in live animals and will aid in the assessment of treatment efficacy. This method could also potentially be adapted to aid the diagnosis and assessment of ALS progression in humans.


Subject(s)
Amyotrophic Lateral Sclerosis/pathology , Diffusion Tensor Imaging , Nerve Degeneration/pathology , Spinal Cord/pathology , Animals , Anisotropy , Disease Models, Animal , Disease Progression , Humans , Mice , Mice, Inbred C57BL , Mice, Transgenic , Microscopy, Electron, Transmission , Motor Neurons/pathology , Superoxide Dismutase/genetics , Superoxide Dismutase-1
19.
Am J Hum Genet ; 83(5): 572-81, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18976727

ABSTRACT

Progressive myoclonus epilepsy (PME) is a syndrome characterized by myoclonic seizures (lightning-like jerks), generalized convulsive seizures, and varying degrees of neurological decline, especially ataxia and dementia. Previously, we characterized three pedigrees of individuals with PME and ataxia, where either clinical features or linkage mapping excluded known PME loci. This report identifies a mutation in PRICKLE1 (also known as RILP for REST/NRSF interacting LIM domain protein) in all three of these pedigrees. The identified PRICKLE1 mutation blocks the PRICKLE1 and REST interaction in vitro and disrupts the normal function of PRICKLE1 in an in vivo zebrafish overexpression system. PRICKLE1 is expressed in brain regions implicated in epilepsy and ataxia in mice and humans, and, to our knowledge, is the first molecule in the noncanonical WNT signaling pathway to be directly implicated in human epilepsy.


Subject(s)
Ataxia/genetics , Homozygote , Mutation , Myoclonic Epilepsies, Progressive/genetics , Tumor Suppressor Proteins/genetics , Amino Acid Sequence , Chromosomes, Human, Pair 12 , Consanguinity , Genes, Recessive , Genetic Markers , Haplotypes , Humans , LIM Domain Proteins , Male , Microsatellite Repeats , Middle Aged , Molecular Sequence Data , Pedigree , Physical Chromosome Mapping , Syndrome
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