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1.
Genet Med ; 25(2): 100327, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36422518

RESUMO

PURPOSE: CAG/CAA repeat expansions in TBP>49 are responsible for spinocerebellar ataxia (SCA) type 17 (SCA17). We previously detected cosegregation of STUB1 variants causing SCA48 with intermediate alleles of TBP in 2 families. This cosegregation questions the existence of SCA48 as a monogenic disease. METHODS: We systematically sequenced TBP repeats in 34 probands of dominant ataxia families with STUB1 variants. In addition, we searched for pathogenic STUB1 variants in probands with expanded alleles of TBP>49 (n = 2) or intermediate alleles of TBP≥40 (n = 47). RESULTS: STUB1 variants were found in half of the TBP40-49 cohort. Mirroring this finding, TBP40-49 alleles were detected in 40% of STUB1 probands. The longer the TBP repeat length, the more likely the occurrence of cognitive impairment (P = .0129) and the faster the disease progression until death (P = .0003). Importantly, 13 STUB1 probands presenting with the full SCA48 clinical phenotype had normal TBP37-39 alleles, excluding digenic inheritance as the sole mode. CONCLUSION: We show that intermediate TBP40-49 alleles act as disease modifiers of SCA48 rather than a STUB1/TBP digenic model. This distinction from what has been proposed before has crucial consequences for genetic counseling in SCA48.


Assuntos
Ataxia Cerebelar , Ataxias Espinocerebelares , Humanos , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/patologia , Ataxia Cerebelar/genética , Fenótipo , Alelos , Expansão das Repetições de Trinucleotídeos/genética , Ubiquitina-Proteína Ligases/genética
2.
Ann Neurol ; 92(1): 122-137, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35411967

RESUMO

OBJECTIVE: Dominant spinocerebellar ataxias (SCA) are characterized by genetic heterogeneity. Some mapped and named loci remain without a causal gene identified. Here we applied next generation sequencing (NGS) to uncover the genetic etiology of the SCA25 locus. METHODS: Whole-exome and whole-genome sequencing were performed in families linked to SCA25, including the French family in which the SCA25 locus was originally mapped. Whole exome sequence data were interrogated in a cohort of 796 ataxia patients of unknown etiology. RESULTS: The SCA25 phenotype spans a slowly evolving sensory and cerebellar ataxia, in most cases attributed to ganglionopathy. A pathogenic variant causing exon skipping was identified in the gene encoding Polyribonucleotide Nucleotidyltransferase PNPase 1 (PNPT1) located in the SCA25 linkage interval. A second splice variant in PNPT1 was detected in a large Australian family with a dominant ataxia also mapping to SCA25. An additional nonsense variant was detected in an unrelated individual with ataxia. Both nonsense and splice heterozygous variants result in premature stop codons, all located in the S1-domain of PNPase. In addition, an elevated type I interferon response was observed in blood from all affected heterozygous carriers tested. PNPase notably prevents the abnormal accumulation of double-stranded mtRNAs in the mitochondria and leakage into the cytoplasm, associated with triggering a type I interferon response. INTERPRETATION: This study identifies PNPT1 as a new SCA gene, responsible for SCA25, and highlights biological links between alterations of mtRNA trafficking, interferonopathies and ataxia. ANN NEUROL 2022;92:122-137.


Assuntos
Ataxia Cerebelar , Interferon Tipo I , Ataxias Espinocerebelares , Ataxia , Austrália , Exorribonucleases , França , Humanos , Interferon Tipo I/genética , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/patologia
3.
Genet Med ; 24(11): 2308-2317, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36056923

RESUMO

PURPOSE: Hereditary spastic paraplegia type 4 is extremely variable in age at onset; the same variant can cause onset at birth or in the eighth decade. We recently discovered that missense variants in SPAST, which influences microtubule dynamics, are associated with earlier onset and more severe disease than truncating variants, but even within the early and late-onset groups there remained significant differences in onset. Given the rarity of the condition, we adapted an extreme phenotype approach to identify genetic modifiers of onset. METHODS: We performed a genome-wide association study on 134 patients bearing truncating pathogenic variants in SPAST, divided into early- and late-onset groups (aged ≤15 and ≥45 years, respectively). A replication cohort of 419 included patients carrying either truncating or missense variants. Finally, age at onset was analyzed in the merged cohort (N = 553). RESULTS: We found 1 signal associated with earlier age at onset (rs10775533, P = 8.73E-6) in 2 independent cohorts and in the merged cohort (N = 553, Mantel-Cox test, P < .0001). Western blotting in lymphocytes of 20 patients showed that this locus tends to upregulate SARS2 expression in earlier-onset patients. CONCLUSION: SARS2 overexpression lowers the age of onset in hereditary spastic paraplegia type 4. Lowering SARS2 or improving mitochondrial function could thus present viable approaches to therapy.


Assuntos
Serina-tRNA Ligase , Paraplegia Espástica Hereditária , Humanos , Estudo de Associação Genômica Ampla , Mutação , Serina-tRNA Ligase/genética , Serina-tRNA Ligase/metabolismo , Paraplegia Espástica Hereditária/genética , Espastina/genética , Espastina/metabolismo
4.
Brain ; 144(9): 2798-2811, 2021 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-34687211

RESUMO

The G4C2-repeat expansion in C9orf72 is the most common cause of frontotemporal dementia and of amyotrophic lateral sclerosis. The variability of age at onset and phenotypic presentations is a hallmark of C9orf72 disease. In this study, we aimed to identify modifying factors of disease onset in C9orf72 carriers using a family-based approach, in pairs of C9orf72 carrier relatives with concordant or discordant age at onset. Linkage and association analyses provided converging evidence for a locus on chromosome Xq27.3. The minor allele A of rs1009776 was associated with an earlier onset (P = 1 × 10-5). The association with onset of dementia was replicated in an independent cohort of unrelated C9orf72 patients (P = 0.009). The protective major allele delayed the onset of dementia from 5 to 13 years on average depending on the cohort considered. The same trend was observed in an independent cohort of C9orf72 patients with extreme deviation of the age at onset (P = 0.055). No association of rs1009776 was detected in GRN patients, suggesting that the effect of rs1009776 was restricted to the onset of dementia due to C9orf72. The minor allele A is associated with a higher SLITRK2 expression based on both expression quantitative trait loci (eQTL) databases and in-house expression studies performed on C9orf72 brain tissues. SLITRK2 encodes for a post-synaptic adhesion protein. We further show that synaptic vesicle glycoprotein 2 and synaptophysin, two synaptic vesicle proteins, were decreased in frontal cortex of C9orf72 patients carrying the minor allele. Upregulation of SLITRK2 might be associated with synaptic dysfunctions and drives adverse effects in C9orf72 patients that could be modulated in those carrying the protective allele. How the modulation of SLITRK2 expression affects synaptic functions and influences the disease onset of dementia in C9orf72 carriers will require further investigations. In summary, this study describes an original approach to detect modifier genes in rare diseases and reinforces rising links between C9orf72 and synaptic dysfunctions that might directly influence the occurrence of first symptoms.


Assuntos
Proteína C9orf72/genética , Degeneração Lobar Frontotemporal/diagnóstico , Degeneração Lobar Frontotemporal/genética , Genes Ligados ao Cromossomo X/genética , Estudo de Associação Genômica Ampla/métodos , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Adulto , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Degeneração Lobar Frontotemporal/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética
5.
Brain ; 143(1): 303-319, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31855245

RESUMO

Homozygous mutations in the progranulin gene (GRN) are associated with neuronal ceroid lipofuscinosis 11 (CLN11), a rare lysosomal-storage disorder characterized by cerebellar ataxia, seizures, retinitis pigmentosa, and cognitive disorders, usually beginning between 13 and 25 years of age. This is a rare condition, previously reported in only four families. In contrast, heterozygous GRN mutations are a major cause of frontotemporal dementia associated with neuronal cytoplasmic TDP-43 inclusions. We identified homozygous GRN mutations in six new patients. The phenotypic spectrum is much broader than previously reported, with two remarkably distinct presentations, depending on the age of onset. A childhood/juvenile form is characterized by classical CLN11 symptoms at an early age at onset. Unexpectedly, other homozygous patients presented a distinct delayed phenotype of frontotemporal dementia and parkinsonism after 50 years; none had epilepsy or cerebellar ataxia. Another major finding of this study is that all GRN mutations may not have the same impact on progranulin protein synthesis. A hypomorphic effect of some mutations is supported by the presence of residual levels of plasma progranulin and low levels of normal transcript detected in one case with a homozygous splice-site mutation and late onset frontotemporal dementia. This is a new critical finding that must be considered in therapeutic trials based on replacement strategies. The first neuropathological study in a homozygous carrier provides new insights into the pathological mechanisms of the disease. Hallmarks of neuronal ceroid lipofuscinosis were present. The absence of TDP-43 cytoplasmic inclusions markedly differs from observations of heterozygous mutations, suggesting a pathological shift between lysosomal and TDP-43 pathologies depending on the mono or bi-allelic status. An intriguing observation was the loss of normal TDP-43 staining in the nucleus of some neurons, which could be the first stage of the TDP-43 pathological process preceding the formation of typical cytoplasmic inclusions. Finally, this study has important implications for genetic counselling and molecular diagnosis. Semi-dominant inheritance of GRN mutations implies that specific genetic counselling should be delivered to children and parents of CLN11 patients, as they are heterozygous carriers with a high risk of developing dementia. More broadly, this study illustrates the fact that genetic variants can lead to different phenotypes according to their mono- or bi-allelic state, which is a challenge for genetic diagnosis.


Assuntos
Demência Frontotemporal/genética , Lipofuscinoses Ceroides Neuronais/genética , Transtornos Parkinsonianos/genética , Progranulinas/genética , Adolescente , Adulto , Idade de Início , Ataxia Cerebelar/genética , Criança , Disfunção Cognitiva/genética , Epilepsia/genética , Feminino , Demência Frontotemporal/diagnóstico por imagem , Demência Frontotemporal/fisiopatologia , Heterozigoto , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Lipofuscinoses Ceroides Neuronais/diagnóstico por imagem , Lipofuscinoses Ceroides Neuronais/fisiopatologia , Transtornos Parkinsonianos/diagnóstico por imagem , Transtornos Parkinsonianos/fisiopatologia , Progranulinas/metabolismo , Splicing de RNA/genética , Doenças Raras , Retinose Pigmentar/genética , Proteinopatias TDP-43/diagnóstico por imagem , Proteinopatias TDP-43/genética , Proteinopatias TDP-43/fisiopatologia , Adulto Jovem
6.
Genet Med ; 22(11): 1851-1862, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32713943

RESUMO

PURPOSE: Pathogenic variants in STUB1 were initially described in autosomal recessive spinocerebellar ataxia type 16 and dominant cerebellar ataxia with cerebellar cognitive dysfunction (SCA48). METHODS: We analyzed a large series of 440 index cerebellar ataxia cases, mostly with dominant inheritance. RESULTS: STUB1 variants were detected in 50 patients. Age at onset and severity were remarkably variable. Cognitive impairment, predominantly frontal syndrome, was observed in 54% of STUB1 variant carriers, including five families with Huntington or frontotemporal dementia disease-like phenotypes associated with ataxia, while no STUB1 variant was found in 115 patients with frontotemporal dementia. We report neuropathological findings of a STUB1 heterozygous patient, showing massive loss of Purkinje cells in the vermis and major loss in the cerebellar hemispheres without atrophy of the pons, hippocampus, or cerebral cortex. This screening of STUB1 variants revealed new features: (1) the majority of patients were women (70%) and (2) "second hits" in AFG3L2, PRKCG, and TBP were detected in three families suggesting synergic effects. CONCLUSION: Our results reveal an unexpectedly frequent (7%) implication of STUB1 among dominantly inherited cerebellar ataxias, and suggest that the penetrance of STUB1 variants could be modulated by other factors, including sex and variants in other ataxia-related genes.


Assuntos
Ataxia Cerebelar , Disfunção Cognitiva , Ataxias Espinocerebelares , Proteases Dependentes de ATP , ATPases Associadas a Diversas Atividades Celulares , Ataxia , Ataxia Cerebelar/genética , Feminino , Humanos , Masculino , Ataxias Espinocerebelares/genética , Ubiquitina-Proteína Ligases
7.
Brain ; 141(12): 3331-3342, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30476002

RESUMO

Hereditary spastic paraplegias (HSPs) are rare neurological disorders caused by progressive distal degeneration of the corticospinal tracts. Among the 79 loci and 65 spastic paraplegia genes (SPGs) involved in HSPs, mutations in SPAST, which encodes spastin, responsible for SPG4, are the most frequent cause of both familial and sporadic HSP. SPG4 is characterized by a clinically pure phenotype associated with restricted involvement of the corticospinal tracts and posterior columns of the spinal cord. It is rarely associated with additional neurological signs. However, both age of onset and severity of the disorder are extremely variable. Such variability is both intra- and inter-familial and may suggest incomplete penetrance, with some patients carrying mutations remaining asymptomatic for their entire life. We analysed a cohort of 842 patients with SPG4-HSP to assess genotype-phenotype correlations. Most patients were French (89%) and had a family history of SPG4-HSP (75%). Age at onset was characterized by a bimodal distribution, with high inter-familial and intra-familial variability, especially concerning first-degree relatives. Penetrance of the disorder was 0.9, complete after 70 years of age. Penetrance was lower in females (0.88 versus 0.94 in males, P = 0.01), despite a more diffuse phenotype with more frequent upper limb involvement. Seventy-seven per cent of pathogenic mutations (missense, frameshift, splice site, nonsense, and deletions) were located in the AAA cassette of spastin, impairing its microtubule-severing activity. A comparison of the missense and truncating mutations revealed a significantly lower age at onset for patients carrying missense mutations than those carrying truncating mutations, explaining the bimodal distribution of the age at onset. The age at onset for patients carrying missense mutations was often before 10 years, sometimes associated with intellectual deficiency. Neuropathological examination of a single case showed degeneration of the spinocerebellar and spinocortical tracts, as well as the posterior columns. However, there were numerous small-diameter processes among unusually large myelinated fibres in the corticospinal tract, suggesting marked regeneration. In conclusion, this large cohort of 842 individuals allowed us to identify a significantly younger age at onset in missense mutation carriers and lower penetrance in females, despite a more severe disorder. Neuropathology in one case showed numerous small fibres suggesting regeneration.


Assuntos
Paraplegia Espástica Hereditária/genética , Espastina/genética , Adulto , Idade de Início , Progressão da Doença , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Fenótipo , Tratos Piramidais/patologia , Índice de Gravidade de Doença , Fatores Sexuais , Paraplegia Espástica Hereditária/patologia , Paraplegia Espástica Hereditária/fisiopatologia , Tratos Espinocerebelares/patologia
8.
Biochim Biophys Acta ; 1862(10): 1861-70, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27425035

RESUMO

X-linked adrenoleukodystrophy (ALD) is a severe neurodegenerative disorder caused by the accumulation of very long-chain fatty acids (VLCFA) due to mutations in the ABCD1 gene. The phenotypic spectrum ranges from a fatal cerebral demyelinating disease in childhood (cerebral ALD) to a progressive myelopathy without cerebral involvement in adulthood (adrenomyeloneuropathy). Because ABCD1 mutations have no predictive value with respect to clinical outcome a role for modifier genes was postulated. We report that the CYP4F2 polymorphism rs2108622 increases the risk of developing cerebral ALD in Caucasian patients. The rs2108622 polymorphism (c.1297G>A) results in an amino acid substitution valine for methionine at position 433 (p.V433M). Using cellular models of VLCFA accumulation, we show that p.V433M decreases the conversion of VLCFA into very long-chain dicarboxylic acids by ω-oxidation, a potential escape route for the deficient peroxisomal ß-oxidation of VLCFA in ALD. Although p.V433M does not affect the catalytic activity of CYP4F2 it reduces CYP4F2 protein levels markedly. These findings open perspectives for therapeutic interventions in a disease with currently limited treatment options.


Assuntos
Adrenoleucodistrofia , Família 4 do Citocromo P450 , Ácidos Graxos , Polimorfismo Genético , Membro 1 da Subfamília D de Transportadores de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília D de Transportadores de Cassetes de Ligação de ATP/metabolismo , Adrenoleucodistrofia/genética , Adrenoleucodistrofia/metabolismo , Linhagem Celular , Família 4 do Citocromo P450/genética , Família 4 do Citocromo P450/metabolismo , Ácidos Graxos/genética , Ácidos Graxos/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Mutação
9.
Am J Hum Genet ; 95(6): 736-43, 2014 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-25434006

RESUMO

Thoracic aortic aneurysm and dissection (TAAD) is an autosomal-dominant disorder with major life-threatening complications. The disease displays great genetic heterogeneity with some forms allelic to Marfan and Loeys-Dietz syndrome, and an important number of cases still remain unexplained at the molecular level. Through whole-exome sequencing of affected members in a large TAAD-affected family, we identified the c.472C>T (p.Arg158(∗)) nonsense mutation in MFAP5 encoding the extracellular matrix component MAGP-2. This protein interacts with elastin fibers and the microfibrillar network. Mutation screening of 403 additional probands identified an additional missense mutation of MFAP5 (c.62G>T [p.Trp21Leu]) segregating with the disease in a second family. Functional analyses performed on both affected individual's cells and in vitro models showed that these two mutations caused pure or partial haploinsufficiency. Thus, alteration of MAGP-2, a component of microfibrils and elastic fibers, appears as an initiating mechanism of inherited TAAD.


Assuntos
Aneurisma da Aorta Torácica/genética , Dissecção Aórtica/genética , Proteínas Contráteis/genética , Glicoproteínas/genética , Haploinsuficiência/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Substituição de Aminoácidos , Dissecção Aórtica/fisiopatologia , Aneurisma da Aorta Torácica/fisiopatologia , Criança , Códon sem Sentido , Proteínas Contráteis/metabolismo , Exoma/genética , Feminino , Fibroblastos , Glicoproteínas/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Pessoa de Meia-Idade , Linhagem , Análise de Sequência de DNA
12.
Genet Med ; 23(6): 1173-1174, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33627829
14.
Brain ; 137(Pt 3): 693-706, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24480483

RESUMO

X-linked adrenoleukodystrophy is the most common peroxisomal disorder. The disease is caused by mutations in the ABCD1 gene that encodes the peroxisomal transporter of very long-chain fatty acids. A defect in the ABCD1 protein results in elevated levels of very long-chain fatty acids in plasma and tissues. The clinical spectrum in males with X-linked adrenoleukodystrophy has been well described and ranges from isolated adrenocortical insufficiency and slowly progressive myelopathy to devastating cerebral demyelination. As in many X-linked diseases, it was assumed that female carriers remain asymptomatic and only a few studies addressed the phenotype of X-linked adrenoleukodystrophy carriers. These studies, however, provided no information on the prevalence of neurological symptoms in the entire population of X-linked adrenoleukodystrophy carriers, since data were acquired in small groups and may be biased towards women with symptoms. Our primary goal was to investigate the symptoms and their frequency in X-linked adrenoleukodystrophy carriers. The secondary goal was to determine if the X-inactivation pattern of the ABCD1 gene was associated with symptomatic status. We included 46 X-linked adrenoleukodystrophy carriers in a prospective cross-sectional cohort study. Our data show that X-linked adrenoleukodystrophy carriers develop signs and symptoms of myelopathy (29/46, 63%) and/or peripheral neuropathy (26/46, 57%). Especially striking was the occurrence of faecal incontinence (13/46, 28%). The frequency of symptomatic women increased sharply with age (from 18% in women <40 years to 88% in women >60 years of age). Virtually all (44/45, 98%) X-linked adrenoleukodystrophy carriers had increased very long-chain fatty acids in plasma and/or fibroblasts, and/or decreased very long-chain fatty acids beta-oxidation in fibroblasts. We did not find an association between the X-inactivation pattern and symptomatic status. We conclude that X-linked adrenoleukodystrophy carriers develop an adrenomyeloneuropathy-like phenotype and there is a strong association between symptomatic status and age. X-linked adrenoleukodystrophy should be considered in the differential diagnosis in women with chronic myelopathy and/or peripheral neuropathy (especially with early faecal incontinence). ABCD1 mutation analysis deserves a place in diagnostic protocols for chronic non-compressive myelopathy.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Adrenoleucodistrofia/fisiopatologia , Doenças do Sistema Nervoso Periférico/fisiopatologia , Doenças da Medula Espinal/fisiopatologia , Membro 1 da Subfamília D de Transportadores de Cassetes de Ligação de ATP , Adrenoleucodistrofia/sangue , Adrenoleucodistrofia/complicações , Adrenoleucodistrofia/genética , Adulto , Fatores Etários , Idoso , Estudos de Coortes , Estudos Transversais , Potenciais Evocados/fisiologia , Feminino , Heterozigoto , Humanos , Pessoa de Meia-Idade , Doenças do Sistema Nervoso Periférico/etiologia , Estudos Prospectivos , Doenças da Medula Espinal/etiologia , Inativação do Cromossomo X/genética , Adulto Jovem
15.
Front Cell Neurosci ; 17: 1155929, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37138765

RESUMO

The GGGGCC intronic repeat expansion within C9ORF72 is the most common genetic cause of ALS and FTD. This mutation results in toxic gain of function through accumulation of expanded RNA foci and aggregation of abnormally translated dipeptide repeat proteins, as well as loss of function due to impaired transcription of C9ORF72. A number of in vivo and in vitro models of gain and loss of function effects have suggested that both mechanisms synergize to cause the disease. However, the contribution of the loss of function mechanism remains poorly understood. We have generated C9ORF72 knockdown mice to mimic C9-FTD/ALS patients haploinsufficiency and investigate the role of this loss of function in the pathogenesis. We found that decreasing C9ORF72 leads to anomalies of the autophagy/lysosomal pathway, cytoplasmic accumulation of TDP-43 and decreased synaptic density in the cortex. Knockdown mice also developed FTD-like behavioral deficits and mild motor phenotypes at a later stage. These findings show that C9ORF72 partial loss of function contributes to the damaging events leading to C9-FTD/ALS.

17.
Neurobiol Aging ; 91: 167.e1-167.e9, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32171590

RESUMO

GRN mutations are frequent causes of familial frontotemporal degeneration. Although there is no clear consensual threshold, plasma progranulin levels represent an efficient biomarker for predicting GRN mutations when decreased. We evaluated plasma levels to determine whether it could also predict age at onset, clinical phenotype, or disease progression in 160 GRN carriers. Importantly, progranulin levels were influenced by gender, with lower levels in male than in female patients in our study. Although we found no correlation with age at onset or with clinical phenotype, we confirmed that decreased level predicts GRN mutations, even in presymptomatic carriers more than four decades before disease onset. We also provided first evidence for the stability of levels throughout longitudinal trajectory in carriers, over a 4-year time span. Finally, we confirmed that progranulin levels constitute a reliable, cost-effective marker, suitable as a screening tool in patients with familial frontotemporal degeneration, and more broadly in patients without family history or with atypical presentations who are less likely to be referred for molecular diagnosis.


Assuntos
Demência Frontotemporal/diagnóstico , Degeneração Lobar Frontotemporal/diagnóstico , Progranulinas/sangue , Adulto , Idade de Início , Idoso , Biomarcadores/sangue , Feminino , França , Demência Frontotemporal/genética , Degeneração Lobar Frontotemporal/genética , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Valor Preditivo dos Testes , Progranulinas/genética , Caracteres Sexuais , Fatores de Tempo
18.
Neurobiol Aging ; 74: 234.e1-234.e8, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30337192

RESUMO

A (GGGGCC)n repeat expansion in C9orf72 gene is the major cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The relations between the repeats size and the age at disease onset (AO) or the clinical phenotype (FTD vs. ALS) were investigated in 125 FTD, ALS, and presymptomatic carriers. Positive correlations were found between repeats number and the AO (p < 10e-4) but our results suggested that the association was mainly driven by age at collection (p < 10e-4). A weaker association was observed with clinical presentation (p = 0.02), which became nonsignificant after adjustment for the age at collection in each group. Importantly, repeats number variably expanded or contracted over time in carriers with multiple blood samples, as well as through generations in parent-offspring pairs, conversely to what occurs in several expansion diseases with anticipation at the molecular level. Finally, this study establishes that measure of repeats number in lymphocytes is not a reliable biomarker predictive of the AO or disease outcome in C9orf72 long expansion carriers.


Assuntos
Esclerose Lateral Amiotrófica/genética , Proteína C9orf72/sangue , Proteína C9orf72/genética , Expansão das Repetições de DNA/genética , Demência Frontotemporal/genética , Heterozigoto , Adulto , Fatores Etários , Idade de Início , Idoso , Esclerose Lateral Amiotrófica/sangue , Esclerose Lateral Amiotrófica/epidemiologia , Coleta de Amostras Sanguíneas , Feminino , Demência Frontotemporal/sangue , Demência Frontotemporal/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo
19.
Microbes Infect ; 10(6): 673-9, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18457972

RESUMO

Tumor necrosis factor (TNF)-related genes are thought to play a role in human malaria. TNF polymorphisms have been associated with severe malaria, mild malaria, and parasitemia. Lymphotoxin-alpha gene (LTA) that belongs to the TNF family is one such candidate gene. Here we report the family-based association analysis of a cis-regulatory lymphotoxin-alpha polymorphism with parasitemia in two independent populations living in Burkina Faso. Analysis of 199 subjects (34 families) living in an urban endemic area revealed the association of the low producing LTA+80A allele with reduced parasitemia. Furthermore, there was evidence of significant LTA+80-by-age and LTA+80-by-gender interactions. In another set of 318 residents (55 families) in a rural endemic area, we found both the association of the low producing LTA+80A allele with reduced parasitemia and LTA+80-by-age and LTA+80-by-gender interactions. This study suggests that LTA+80 polymorphism influences parasitemia and acts in an age- and gender-dependent manner.


Assuntos
Linfotoxina-alfa/genética , Malária Falciparum/genética , Parasitemia/genética , Plasmodium falciparum , Polimorfismo Genético , Fator de Necrose Tumoral alfa/genética , Adolescente , Adulto , Fatores Etários , Alelos , Animais , Criança , Pré-Escolar , Família , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Preconceito
20.
Geriatr Psychol Neuropsychiatr Vieil ; 16(3): 289-297, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30168435

RESUMO

Early-onset Alzheimer's disease (EOAD) and frontotemporal lobar dementia (FTLD) account for the majority of early-onset dementia (onset before 65 years). The high frequency of genetic forms is a common feature of EOAD and FTLD. A lot of efforts have been done to unravel the genetic bases of monogenic forms of these two diseases. PSEN1, APP and PSEN2 are the major causes of monogenic EOAD while GRN, MAPT and C9ORF72 are the most frequently mutated genes in familial FTLD. Besides, the rise of new generation sequencing technologies (NGS) during the last decade allowed a better description of the genetic architecture. A myriad of genes implicated each in a lower number of families with variable penetrance have been highlighted, especially in FTLD. The genetic heterogeneity and it contribution to the clinical variability have been described with more detailed and the process of molecular diagnostic has been modified as well. Here we propose to review old and recent findings about the contribution of genetic factors into these two major early-onset dementia diseases. The impact on the diagnostic and on the knowledge of associated pathophysiological mechanisms is also discussed.


Assuntos
Doença de Alzheimer/genética , Demência Frontotemporal/genética , Adulto , Idade de Início , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/epidemiologia , Feminino , Demência Frontotemporal/diagnóstico , Demência Frontotemporal/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Proteínas do Tecido Nervoso/genética , Patologia Molecular
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