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1.
Acta Neuropathol ; 147(1): 73, 2024 Apr 19.
Article En | MEDLINE | ID: mdl-38641715

The most prominent genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) is a repeat expansion in the gene C9orf72. Importantly, the transcriptomic consequences of the C9orf72 repeat expansion remain largely unclear. Here, we used short-read RNA sequencing (RNAseq) to profile the cerebellar transcriptome, detecting alterations in patients with a C9orf72 repeat expansion. We focused on the cerebellum, since key C9orf72-related pathologies are abundant in this neuroanatomical region, yet TDP-43 pathology and neuronal loss are minimal. Consistent with previous work, we showed a reduction in the expression of the C9orf72 gene and an elevation in homeobox genes, when comparing patients with the expansion to both patients without the C9orf72 repeat expansion and control subjects. Interestingly, we identified more than 1000 alternative splicing events, including 4 in genes previously associated with ALS and/or FTLD. We also found an increase of cryptic splicing in C9orf72 patients compared to patients without the expansion and controls. Furthermore, we demonstrated that the expression level of select RNA-binding proteins is associated with cryptic splice junction inclusion. Overall, this study explores the presence of widespread transcriptomic changes in the cerebellum, a region not confounded by severe neurodegeneration, in post-mortem tissue from C9orf72 patients.


Amyotrophic Lateral Sclerosis , C9orf72 Protein , Cerebellum , Frontotemporal Lobar Degeneration , Humans , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/metabolism , Amyotrophic Lateral Sclerosis/pathology , C9orf72 Protein/genetics , C9orf72 Protein/metabolism , Cerebellum/pathology , DNA Repeat Expansion/genetics , Frontotemporal Lobar Degeneration/genetics , Frontotemporal Lobar Degeneration/metabolism , Frontotemporal Lobar Degeneration/pathology , Gene Expression Profiling , Transcriptome
2.
Perfusion ; 39(3): 543-554, 2024 Apr.
Article En | MEDLINE | ID: mdl-36625378

BACKGROUND: Anti-human leukocyte antigen (HLA)-antibody production represents a major barrier to heart transplantation, limiting recipient compatibility with potential donors and increasing the risk of complications with poor waiting-list outcomes. Currently there is no consensus to when desensitization should take place, and through what mechanism, meaning that sensitized patients must wait for a compatible donor for many months, if not years. We aimed to determine if intraoperative immunoadsorption could provide a potential desensitization methodology. METHODS: Anti-HLA antibody-containing whole blood was added to a Cardiopulmonary bypass (CPB) circuit set up to mimic a 20 kg patient undergoing heart transplantation. Plasma was separated and diverted to a standalone, secondary immunoadsorption system, with antibody-depleted plasma returned to the CPB circuit. Samples for anti-HLA antibody definition were taken at baseline, when combined with the CPB prime (on bypass), and then every 20 min for the duration of treatment (total 180 min). RESULTS: A reduction in individual allele median fluorescence intensity (MFI) to below clinically relevant levels (<1000 MFI), and in the majority of cases below the lower positive detection limit (<500 MFI), even in alleles with a baseline MFI >4000 was demonstrated. Reduction occurred in all cases within 120 min, demonstrating efficacy in a time period usual for heart transplantation. Flowcytometric crossmatching of suitable pseudo-donor lymphocytes demonstrated a change from T cell and B cell positive channel shifts to negative, demonstrating a reduction in binding capacity. CONCLUSIONS: Intraoperative immunoadsorption in an ex vivo setting demonstrates clinically relevant reductions in anti-HLA antibodies within the normal timeframe for heart transplantation. This method represents a potential desensitization technique that could enable sensitized children to accept a donor organ earlier, even in the presence of donor-specific anti-HLA antibodies.


Heart Transplantation , Kidney Transplantation , Child , Humans , Cardiopulmonary Bypass , Tissue Donors , HLA Antigens
3.
Perfusion ; 38(7): 1530-1533, 2023 10.
Article En | MEDLINE | ID: mdl-35840547

BACKGROUND: Sensitised patients undergoing Human Leukocyte Antigen-incompatible transplantation are at increased risk of hyperacute rejection and may be predisposed to antibody-mediated rejection, chronic lung allograft dysfunction and higher mortality. CASE: We present a case of primary lung transplantation in the setting of late identification of donor specific antibodies treated with intraoperative target plasma exchange. The patient was treated with fresh human plasma to a final volume of 1.5 times the patient's systemic circulation. From a pre-transplant mean fluorescence intensity of 5002, donor-specific antibodies were undetectable following plasma exchange on single antigen bead assay. CONCLUSIONS: This method represents a potential desensitisation technique for use in the intraoperative period.


Lung Transplantation , Plasma Exchange , Humans , Infant , HLA Antigens , Tissue Donors , Transplantation, Homologous
4.
J Heart Lung Transplant ; 40(11): 1433-1442, 2021 11.
Article En | MEDLINE | ID: mdl-34187714

BACKGROUND: Intraoperative anti-A/B immunoadsorption (ABO-IA) was recently introduced for ABO-incompatible heart transplantation. Here we report the first case series of patients transplanted with ABO-IA, and compare outcomes with those undergoing plasma exchange facilitated ABO-incompatible heart transplantation (ABO-PE). METHODS: Data were retrospectively analysed on all ABO-incompatible heart transplants undertaken at a single centre between January 1, 2000 and June 1, 2020. Data included all routine laboratory tests, demographics and pre-operative characteristics, intraoperative details and post-operative outcomes. Primary outcome measures were volume of blood product transfusions, maximum post-transplant isohaemagglutinin titres, occurrence of rejection and graft survival. Secondary outcome measures were length of intensive care and hospital stay. Demographic and survival data were also obtained for ABO-compatible transplants during the same time period for comparison. RESULTS: Thirty-seven patients underwent ABO-incompatible heart transplantation, with 27 (73%) using ABO-PE and 10 (27%) using ABO-IA. ABO-IA patients were significantly older than ABO-PE patients (p < 0.001) and the total volume of blood products transfused during the hospital admission was significantly lower (164 [126-212] ml/kg vs 323 [268-379] ml/kg, p < 0.001). No significant differences were noted between methods in either pre or post-transplant maximum isohaemagglutinin titres, incidence of rejection, length of intensive care or total hospital stay. Survival comparison showed no significant difference between antibody reduction methods, or indeed ABO-compatible transplants (p = 0.6). CONCLUSIONS: This novel technique appears to allow a significantly older population than typical to undergo ABO-incompatible heart transplantation, as well as significantly reducing blood product utilization. Furthermore, intraoperative anti-A/B immunoadsorption does not demonstrate increased early post-transplant isohaemagglutinin accumulation or rates of rejection compared to ABO-PE. Early survival is equivalent between ABO-IA, ABO-PE and ABO-compatible heart transplantation.


ABO Blood-Group System/immunology , Antibodies/immunology , Blood Group Incompatibility/immunology , Graft Rejection/prevention & control , Heart Transplantation/methods , Intraoperative Care/methods , Plasmapheresis/methods , Blood Group Incompatibility/complications , Blood Group Incompatibility/therapy , Child , Child, Preschool , Female , Follow-Up Studies , Graft Rejection/immunology , Graft Survival , Humans , Infant , Male , Retrospective Studies
5.
Perfusion ; 36(1): 34-37, 2021 01.
Article En | MEDLINE | ID: mdl-32493108

Traditionally, ABO-incompatible heart transplantation was accomplished using a plasma exchange technique to remove recipient plasma containing donor-incompatible anti-A/B isohaemagglutinins. However, this technique exposed patients to large volumes of allogeneic blood and blood products (up to three times the patient's circulating volume). In 2018, we published the first reported case of an ABO-incompatible heart transplant using an intraoperative immunoadsorption technique which minimises the exposure to blood products by specifically targeting anti-A/B isohaemagglutinins. We have subsequently used this technique in all children undergoing ABO-incompatible heart transplantation and become convinced of its efficacy in this population while observing no adverse effects. This article outlines the practical details required to perform the technique in order to avoid hyperacute rejection.


Blood Group Incompatibility , Heart Transplantation , ABO Blood-Group System , Child , Hospitals , Humans , Plasmapheresis
6.
Perfusion ; 35(2): 169-171, 2020 03.
Article En | MEDLINE | ID: mdl-31303113

Necrotizing pneumonia can lead to respiratory insufficiency in previously healthy children. Extracorporeal membrane oxygenation can be used for hemodynamic salvage and subsequent lung rest awaiting recovery. We present a case of a child initially placed on veno-arterial extracorporeal membrane oxygenation and converted to veno-venous extracorporeal membrane oxygenation. This was done under deep hypothermia in the operating theater.


Cannula/standards , Extracorporeal Membrane Oxygenation/methods , Hypothermia, Induced/methods , Pneumonia, Necrotizing/therapy , Child, Preschool , Female , Humans
7.
World J Pediatr Congenit Heart Surg ; 11(4): NP117-NP119, 2020 Jul.
Article En | MEDLINE | ID: mdl-29334830

Congenital hyperinsulinism is a clinical syndrome of pancreatic ß-cell dysfunction characterized by failure to suppress insulin secretion in the presence of hypoglycemia. Here, we describe the concerns, the techniques used to ameliorate these potential problems, and the outcomes for a child with this condition undergoing cardiopulmonary bypass for correction of an atrial septal defect.


Cardiac Surgical Procedures/methods , Cardiopulmonary Bypass/methods , Heart Defects, Congenital/surgery , Hyperinsulinism/congenital , Heart Defects, Congenital/diagnosis , Humans , Hyperinsulinism/diagnosis , Infant , Male
8.
Perfusion ; 34(4): 334-336, 2019 05.
Article En | MEDLINE | ID: mdl-30628549

Sickle cell anaemia results from homozygosity of an A-T point mutation leading to a substitution of glutamic acid for valine at point 6 of the ß-globin gene. A person with sickle cell trait inherits one normal and one mutated allele. Patients with sickle cell anaemia, and to a lesser extent sickle cell trait, have a wide spectrum of haemostatic abnormalities. Here we describe the problems faced in obtaining an accurate activated clotting time measurement, in a patient with sickle cell trait, prior to commencement of cardiopulmonary bypass for decannulation of Berlin Heart.


Anemia, Sickle Cell/blood , Blood Coagulation/physiology , Sickle Cell Trait/blood , Child, Preschool , Humans , Male
9.
J Heart Lung Transplant ; 37(4): 451-457, 2018 04.
Article En | MEDLINE | ID: mdl-28554587

BACKGROUND: Since 1996, ABO-incompatible heart transplantation has been undertaken by performing whole-body plasma exchange to remove isohemagglutinins using the cardiopulmonary bypass (CPB) circuit at the time of transplantation. This requires large volumes of donated blood and blood products, causes hemodynamic instability during the exchange transfusion, and limits practical use to small children. We sought to determine the efficacy of anti-A/B immunoadsorption within the CPB circuit on removal of isohemagglutinins in an ex vivo setting before its use clinically. METHODS: An anti-A/B immunoadsorption column was placed into a CPB circuit mimicking a typical ABO-incompatible transplant patient, which had been primed with type O whole human blood. Samples were taken for determination of isohemagglutinin titers following each plasma volume pass through the anti-A/B immunoadsorption column. RESULTS: There was a linear decrease of at least 1 dilution seen in both anti-A and anti-B IgG and IgM antibodies with each plasma volume pass through the column. This predictable removal allowed the formulation of selection criteria for ABO-incompatible heart transplantation given the reciprocal of titer and patient weight. This degree of predictability allowed us to use it successfully in the clinical setting, reducing antibodies to an undetectable level during ABO-incompatible heart transplantation. CONCLUSIONS: The incorporation of an anti-A/B immunoadsorption column into the extracorporeal circuit reduces allogeneic blood product requirement for ABO-incompatible heart transplantation, while providing efficacious removal of anti-A and anti-B isohemagglutinins. This can be undertaken within the time period of CPB before graft reperfusion and expands the potential recipient pool to larger patients with higher isohemagglutinin titers.


ABO Blood-Group System , Blood Group Incompatibility , Cardiopulmonary Bypass/methods , Heart Transplantation/methods , Immunosorbent Techniques , Feasibility Studies , Hemagglutinins , Humans , Models, Cardiovascular , Patient-Specific Modeling
10.
Perfusion ; 33(3): 232-234, 2018 04.
Article En | MEDLINE | ID: mdl-28870116

Beta (ß)-thalassemia is a blood disorder with an incidence of 1 in 100,000.1 This case report outlines a patient with ß-thalassemia requiring cardiopulmonary bypass (CPB) and the measures taken to ensure an uneventful procedure.


Cardiac Surgical Procedures/methods , Cardiopulmonary Bypass/methods , Heart Septal Defects/complications , Heart Septal Defects/surgery , beta-Thalassemia/complications , Child , Humans , Infant , Male
11.
Perfusion ; 32(5): 378-382, 2017 Jul.
Article En | MEDLINE | ID: mdl-28110616

OBJECTIVES: Colloid osmotic pressure (COP) is a major determinant of fluid shift in paediatric patients undergoing corrective surgery for congenital heart disease (CHD) using cardiopulmonary bypass (CPB). However, very few baseline data are available for those patients requiring surgery within the first few weeks and months of life. Our aim was to determine if our CHD population exhibited COP similar to that of other extremely ill subsets of patients and, if so, whether this related to risk stratification model scores. METHODS: Thirty consecutive patients under 10 kg underwent cardiac surgery with CPB. Data were collected on COP, albumin concentration, prime composition, post-operative length of ventilation and intensive care unit (ICU) stay as well as risk stratification utilising Risk Adjustment for Congenital Heart Surgery (RACHS-1) and Partial Risk Adjustment in Surgery (PRAiS) scoring systems. RESULTS: The patients had a mean pre-bypass COP of 13.9±2.5 mmHg. A significant negative correlation was observed between pre-operative baseline COP and length of ventilation (r=0.7; p<0.001) and a significant negative correlation between PRAiS (r=0.64; p<0.001) and RACHS-1 (r=0.5; p=0.004) scores and baseline COP was seen. CONCLUSIONS: Neonatal and paediatric patients requiring surgical correction of complex congenital cardiac malformations exhibit extremely low baseline COP, comparable to other sick neonatal populations, and are lower than those previously reported. Baseline COP correlates significantly with predicted survival rates and time spent on a ventilator.


Cardiopulmonary Bypass/methods , Heart Defects, Congenital/surgery , Osmotic Pressure , Child, Preschool , Disease-Free Survival , Female , Heart Defects, Congenital/mortality , Humans , Infant , Male , Survival Rate
12.
Neurobiol Aging ; 33(2): 424.e23-4, 2012 Feb.
Article En | MEDLINE | ID: mdl-21074900

Insertion and deletion variants (indels) within poly glycine tracts of fused in sarcoma (FUS) were initially reported as causative of disease in amyotrophic lateral sclerosis (ALS). Subsequent studies identified similar indels in controls and suggested that these indels may confer susceptibility to ALS. We aimed to elucidate the role of previously published and novel exonic indels in FUS in an extensive cohort of 630 ALS patients and 1063 controls. We detected indels in FUS exons 5, 6, 12, and 14 with similar frequencies in patients (0.95%) and controls (0.75%). Exonic indels in poly glycine tracts were also observed with similar frequencies. The largest indel (p.Gly138_Tyr143del) was observed in 1 control. In 1 patient, a 3 base pair deletion in exon 14 (p.Gly475del) was identified, however in vitro studies did not reveal abnormal localization of p.Gly475del mutant FUS. These findings suggest that not all exonic indels in FUS cause disease.


Amyotrophic Lateral Sclerosis/genetics , Exons/genetics , Genetic Predisposition to Disease/genetics , INDEL Mutation/genetics , Peptides/genetics , RNA-Binding Protein FUS/genetics , Aged , Aged, 80 and over , Amyotrophic Lateral Sclerosis/epidemiology , Female , Genetic Predisposition to Disease/epidemiology , Humans , Male , Prevalence , Reproducibility of Results , Risk Assessment , Risk Factors , Sensitivity and Specificity , United States/epidemiology
13.
J Neurol Neurosurg Psychiatry ; 82(2): 196-203, 2011 Feb.
Article En | MEDLINE | ID: mdl-20562461

BACKGROUND: Frontotemporal dementia-amyotrophic lateral sclerosis (FTD-ALS) is a heritable form of FTD, but the gene(s) responsible for the majority of autosomal dominant FTD-ALS cases have yet to be found. Previous studies have identified a region on chromosome 9p that is associated with FTD and ALS. METHODS: The authors report the clinical, volumetric MRI, neuropathological and genetic features of a new chromosome 9p-linked FTD-ALS family, VSM-20. RESULTS: Ten members of family VSM-20 displayed heterogeneous clinical phenotypes of isolated behavioural-variant FTD (bvFTD), ALS or a combination of the two. Parkinsonism was common, with one individual presenting with a corticobasal syndrome. Analysis of structural MRI scans from five affected family members revealed grey- and white-matter loss that was most prominent in the frontal lobes, with mild parietal and occipital lobe atrophy, but less temporal lobe atrophy than in 10 severity-matched sporadic bvFTD cases. Autopsy in three family members showed a consistent and unique subtype of FTLD-TDP pathology. Genome-wide linkage analysis conclusively linked family VSM-20 to a 28.3 cM region between D9S1808 and D9S251 on chromosome 9p, reducing the published minimal linked region to a 3.7 Mb interval. Genomic sequencing and expression analysis failed to identify mutations in the 10 known and predicted genes within this candidate region, suggesting that next-generation sequencing may be needed to determine the mutational mechanism associated with chromosome 9p-linked FTD-ALS. CONCLUSIONS: Family VSM-20 significantly reduces the region linked to FTD-ALS on chromosome 9p. A distinct pattern of brain atrophy and neuropathological findings may help to identify other families with FTD-ALS caused by this genetic abnormality.


Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/pathology , Chromosomes, Human, Pair 9/genetics , Frontotemporal Dementia/genetics , Frontotemporal Dementia/pathology , Adult , Amyotrophic Lateral Sclerosis/complications , Autopsy , Brain/pathology , DNA Mutational Analysis , Family , Female , Frontotemporal Dementia/complications , Genetic Linkage , Genetic Predisposition to Disease , Genome-Wide Association Study , Haplotypes , Humans , Immunohistochemistry , Lod Score , Magnetic Resonance Imaging , Male , Middle Aged , Parkinson Disease/genetics , Pedigree
14.
Hum Mutat ; 31(5): E1377-89, 2010 May.
Article En | MEDLINE | ID: mdl-20232451

Mutations in the gene encoding fused in sarcoma (FUS) were recently identified as a novel cause of amyotrophic lateral sclerosis (ALS), emphasizing the genetic heterogeneity of ALS. We sequenced the genes encoding superoxide dismutase (SOD1), TAR DNA-binding protein 43 (TARDBP) and FUS in 99 sporadic and 17 familial ALS patients ascertained at Mayo Clinic. We identified two novel mutations in FUS in two out of 99 (2.0%) sporadic ALS patients and established the de novo occurrence of one FUS mutation. In familial patients, we identified three (17.6%) SOD1 mutations, while FUS and TARDBP mutations were excluded. The de novo FUS mutation (g.10747A>G; IVS13-2A>G) affects the splice-acceptor site of FUS intron 13 and was shown to induce skipping of FUS exon 14 leading to the C-terminal truncation of FUS (p.G466VfsX14). Subcellular localization studies showed a dramatic increase in the cytoplasmic localization of FUS and a reduction of normal nuclear expression in cells transfected with truncated compared to wild-type FUS. We further identified a novel in-frame insertion/deletion mutation in FUS exon 12 (p.S402_P411delinsGGGG) which is predicted to expand a conserved poly-glycine motif. Our findings extend the mutation spectrum in FUS leading to ALS and describe the first de novo mutation in FUS.


Amyotrophic Lateral Sclerosis/genetics , RNA-Binding Protein FUS/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Amyotrophic Lateral Sclerosis/metabolism , Case-Control Studies , Child , Child, Preschool , DNA Mutational Analysis , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Female , Humans , Male , Middle Aged , Mutation , Pedigree , RNA-Binding Protein FUS/metabolism , Superoxide Dismutase/genetics , Superoxide Dismutase/metabolism , Superoxide Dismutase-1 , Young Adult
15.
Neurobiol Aging ; 31(5): 725-31, 2010 May.
Article En | MEDLINE | ID: mdl-18667258

Mutations in three genes (PSEN1, PSEN2, and APP) have been identified in patients with early-onset (<65 years) Alzheimer's disease (AD). We performed a screening for mutations in the coding regions of presenilins, as well as exons 16 and 17 of the APP gene in a total of 231 patients from the Iberian peninsular with a clinical diagnosis of early-onset AD (mean age at onset of 52.9 years; range 31-64). We found three novel mutations in PSEN1, one novel mutation in PSEN2, and a novel mutation in the APP gene. Four previously described mutations in PSEN1 were also found. The same analysis was carried in 121 elderly healthy controls from the Iberian peninsular, and a set of 130 individuals from seven African populations belonging to the Centre d'Etude du Polymorphisme Humain-Human Genome Diversity Panel (CEPH-HGDP), in order to determine the extent of normal variability in these genes. Interestingly, in the latter series, we found five new non-synonymous changes in all three genes and a presenilin 2 variant (R62H) that has been previously related to AD. In some of these mutations, the pathologic consequence is uncertain and needs further investigation. To address this question we propose and use a systematic algorithm to classify the putative pathology of AD mutations.


Alzheimer Disease/genetics , Amyloid beta-Protein Precursor/genetics , Presenilin-1/genetics , Presenilin-2/genetics , Adult , Africa , Aged , Exons/genetics , Genetic Predisposition to Disease/genetics , Genetic Testing , Humans , Middle Aged , Mutation/genetics , Portugal , Spain
16.
Am J Pathol ; 175(4): 1598-609, 2009 Oct.
Article En | MEDLINE | ID: mdl-19717642

Here, we describe the generation and characterization of a novel tau transgenic mouse model (mTau) that overexpresses wild-type murine tau protein by twofold compared with endogenous levels. Transgenic tau expression was driven by a BAC transgene containing the entire wild-type mouse tau locus, including the endogenous promoter and the regulatory elements associated with the tau gene. The mTau model therefore differs from other tau models in that regulation of the genomic mouse transgene mimics that of the endogenous gene, including normal exon splicing regulation. Biochemical data from the mTau mice demonstrated that modest elevation of mouse tau leads to tau hyperphosphorylation at multiple pathologically relevant epitopes and accumulation of sarkosyl-insoluble tau. The mTau mice show a progressive increase in hyperphosphorylated tau pathology with age up to 15 to 18 months, which is accompanied by gliosis and vacuolization. In contrast, older mice show a decrease in tau pathology levels, which may represent hippocampal neuronal loss occurring in this wild-type model. Collectively, these results describe a novel model of tauopathy that develops pathological changes reminiscent of early stage Alzheimer's disease and other related neurodegenerative diseases, achieved without overexpression of a mutant human tau transgene. This model will provide an important tool for understanding the early events leading to the development of tau pathology and a model for analysis of potential therapeutic targets for sporadic tauopathies.


Nerve Degeneration/complications , Nerve Degeneration/pathology , Tauopathies/complications , Tauopathies/pathology , tau Proteins/metabolism , Aging/pathology , Animals , Axons/pathology , Axons/ultrastructure , Breeding , Chromosomes, Artificial, Bacterial/genetics , Gene Expression Regulation , Genetic Vectors/genetics , Genome/genetics , Mice , Mice, Transgenic , Myelin Sheath/pathology , Myelin Sheath/ultrastructure , Phosphorylation , Solubility
17.
Brain ; 132(Pt 3): 583-91, 2009 Mar.
Article En | MEDLINE | ID: mdl-19158106

Mutations in the progranulin gene (GRN) are an important cause of frontotemporal lobar degeneration (FTLD) with ubiquitin and TAR DNA-binding protein 43 (TDP43)-positive pathology. The clinical presentation associated with GRN mutations is heterogeneous and may include clinical probable Alzheimer's disease. All GRN mutations identified thus far cause disease through a uniform disease mechanism, i.e. the loss of functional GRN or haploinsufficiency. To determine if expression of GRN in plasma could predict GRN mutation status and could be used as a biological marker, we optimized a GRN ELISA and studied plasma samples of a consecutive clinical FTLD series of 219 patients, 70 control individuals, 72 early-onset probable Alzheimer's disease patients and nine symptomatic and 18 asymptomatic relatives of GRN mutation families. All FTLD patients with GRN loss-of-function mutations showed significantly reduced levels of GRN in plasma to about one third of the levels observed in non-GRN carriers and control individuals (P < 0.001). No overlap in distributions of GRN levels was observed between the eight GRN loss-of-function mutation carriers (range: 53-94 ng/ml) and 191 non-GRN mutation carriers (range: 115-386 ng/ml). Similar low levels of GRN were identified in asymptomatic GRN mutation carriers. Importantly, ELISA analyses also identified one probable Alzheimer's disease patient (1.4%) carrying a loss-of-function mutation in GRN. Biochemical analyses further showed that the GRN ELISA only detects full-length GRN, no intermediate granulin fragments. This study demonstrates that using a GRN ELISA in plasma, pathogenic GRN mutations can be accurately detected in symptomatic and asymptomatic carriers. The approximately 75% reduction in full-length GRN, suggests an unbalanced GRN metabolism in loss-of-function mutation carriers whereby more GRN is processed into granulins. We propose that plasma GRN levels could be used as a reliable and inexpensive tool to identify all GRN mutation carriers in early-onset dementia populations and asymptomatic at-risk individuals.


Dementia/diagnosis , Intercellular Signaling Peptides and Proteins/blood , Intercellular Signaling Peptides and Proteins/genetics , Mutation , Adult , Aged , Alzheimer Disease/blood , Alzheimer Disease/diagnosis , Alzheimer Disease/genetics , Biomarkers/blood , Cohort Studies , Dementia/blood , Dementia/genetics , Enzyme-Linked Immunosorbent Assay/methods , Family Health , Female , Heterozygote , Humans , Male , Middle Aged , Progranulins , Sensitivity and Specificity
18.
PLoS Genet ; 4(9): e1000193, 2008 Sep 19.
Article En | MEDLINE | ID: mdl-18802454

The TAR DNA-binding protein 43 (TDP-43) has been identified as the major disease protein in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin inclusions (FTLD-U), defining a novel class of neurodegenerative conditions: the TDP-43 proteinopathies. The first pathogenic mutations in the gene encoding TDP-43 (TARDBP) were recently reported in familial and sporadic ALS patients, supporting a direct role for TDP-43 in neurodegeneration. In this study, we report the identification and functional analyses of two novel and one known mutation in TARDBP that we identified as a result of extensive mutation analyses in a cohort of 296 patients with variable neurodegenerative diseases associated with TDP-43 histopathology. Three different heterozygous missense mutations in exon 6 of TARDBP (p.M337V, p.N345K, and p.I383V) were identified in the analysis of 92 familial ALS patients (3.3%), while no mutations were detected in 24 patients with sporadic ALS or 180 patients with other TDP-43-positive neurodegenerative diseases. The presence of p.M337V, p.N345K, and p.I383V was excluded in 825 controls and 652 additional sporadic ALS patients. All three mutations affect highly conserved amino acid residues in the C-terminal part of TDP-43 known to be involved in protein-protein interactions. Biochemical analysis of TDP-43 in ALS patient cell lines revealed a substantial increase in caspase cleaved fragments, including the approximately 25 kDa fragment, compared to control cell lines. Our findings support TARDBP mutations as a cause of ALS. Based on the specific C-terminal location of the mutations and the accumulation of a smaller C-terminal fragment, we speculate that TARDBP mutations may cause a toxic gain of function through novel protein interactions or intracellular accumulation of TDP-43 fragments leading to apoptosis.


Amyotrophic Lateral Sclerosis/genetics , DNA-Binding Proteins/genetics , Mutation, Missense , Adult , Aged , Aged, 80 and over , Alleles , Amyotrophic Lateral Sclerosis/metabolism , Cell Line, Tumor , Cohort Studies , DNA Mutational Analysis , DNA-Binding Proteins/metabolism , Female , Humans , Male , Middle Aged , Neurodegenerative Diseases/genetics , Neurodegenerative Diseases/metabolism , Pedigree
19.
Hum Mol Genet ; 17(23): 3631-42, 2008 Dec 01.
Article En | MEDLINE | ID: mdl-18723524

Loss-of-function mutations in progranulin (GRN) cause ubiquitin- and TAR DNA-binding protein 43 (TDP-43)-positive frontotemporal dementia (FTLD-U), a progressive neurodegenerative disease affecting approximately 10% of early-onset dementia patients. Here we expand the role of GRN in FTLD-U and demonstrate that a common genetic variant (rs5848), located in the 3'-untranslated region (UTR) of GRN in a binding-site for miR-659, is a major susceptibility factor for FTLD-U. In a series of pathologically confirmed FTLD-U patients without GRN mutations, we show that carriers homozygous for the T-allele of rs5848 have a 3.2-fold increased risk to develop FTLD-U compared with homozygous C-allele carriers (95% CI: 1.50-6.73). We further demonstrate that miR-659 can regulate GRN expression in vitro, with miR-659 binding more efficiently to the high risk T-allele of rs5848 resulting in augmented translational inhibition of GRN. A significant reduction in GRN protein was observed in homozygous T-allele carriers in vivo, through biochemical and immunohistochemical methods, mimicking the effect of heterozygous loss-of-function GRN mutations. In support of these findings, the neuropathology of homozygous rs5848 T-allele carriers frequently resembled the pathological FTLD-U subtype of GRN mutation carriers. We suggest that the expression of GRN is regulated by miRNAs and that common genetic variability in a miRNA binding-site can significantly increase the risk for FTLD-U. Translational regulation by miRNAs may represent a common mechanism underlying complex neurodegenerative disorders.


DNA-Binding Proteins/metabolism , Dementia/genetics , Genetic Variation , Intercellular Signaling Peptides and Proteins/chemistry , Intercellular Signaling Peptides and Proteins/genetics , MicroRNAs/metabolism , Aged , Base Sequence , Binding Sites , Brain/metabolism , Dementia/metabolism , Female , Gene Expression Regulation , Genotype , Humans , Intercellular Signaling Peptides and Proteins/metabolism , Male , MicroRNAs/chemistry , MicroRNAs/genetics , Middle Aged , Molecular Sequence Data , Mutation , Progranulins , Protein Biosynthesis
20.
Alzheimer Dis Assoc Disord ; 22(3): 299-307, 2008.
Article En | MEDLINE | ID: mdl-18580586

OBJECTIVE: Early onset familial Alzheimer disease (EOFAD) can be caused by mutations in genes for amyloid precursor protein, presenilin 1 (PSEN1), or presenilin 2 (PSEN2). There is considerable phenotypic variability in EOFAD, including some patients with spastic paraparesis. The objective is to describe clinical and neuropathologic features of a family with a PSEN1 mutation that has been reported previously, without autopsy confirmation, in a single Greek family whose affected members presented with memory loss in their 30s, as well as variable limb spasticity and seizures. METHODS: We prospectively evaluated 2 children (son and daughter) with EOFAD and reviewed medical records on their mother. Archival material from the autopsy of the mother was reviewed and postmortem studies were performed on the brain of the daughter. RESULTS: All 3 individuals in this family had disease onset in their 30s, with cognitive deficits in multiple domains, including memory, language, and attention, as well as less common features such as spastic dysarthria, limb spasticity, and seizures. At autopsy both the mother and her daughter had pathologic findings of Alzheimer disease, and histologic evidence of corticospinal tract degeneration. Genetic studies revealed a mutation in PSEN1 leading to an asparagine to serine substitution at amino acid residue 135 (N135S) in presenilin 1. CONCLUSIONS: This is the first description of neuropathologic findings in EOFAD owing to N135S PSEN1 mutation. The clinical phenotype was remarkable for spastic dysarthria, limb spasticity, and seizures, in addition to more typical features of EOFAD.


Alzheimer Disease/genetics , Alzheimer Disease/pathology , Brain/pathology , Presenilin-1/genetics , Adult , Age of Onset , Alzheimer Disease/complications , DNA Mutational Analysis , Dysarthria/etiology , Humans , Immunohistochemistry , Male , Mutation , Nerve Degeneration/etiology , Nerve Degeneration/pathology , Paraparesis, Spastic/etiology , Pedigree , Polymerase Chain Reaction , Pyramidal Tracts/pathology , Seizures/etiology
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