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1.
Mov Disord ; 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38576116

RESUMEN

BACKGROUND: FRMD5 variants were recently identified in patients with developmental delay, ataxia, and eye movement abnormalities. OBJECTIVES: We describe 2 patients presenting with childhood-onset ataxia, nystagmus, and seizures carrying pathogenic de novo FRMD5 variants. Weighted gene co-expression network analysis (WGCNA) was performed to gain insights into the function of FRMD5 in the brain. METHODS: Trio-based whole-exome sequencing was performed in both patients, and CoExp web tool was used to conduct WGCNA. RESULTS: Both patients presented with developmental delay, childhood-onset ataxia, nystagmus, and seizures. Previously unreported findings were diffuse choreoathetosis and dystonia of the hands (patient 1) and areas of abnormal magnetic resonance imaging signal in the white matter (patient 2). WGCNA showed that FRMD5 belongs to gene networks involved in neurodevelopment and oligodendrocyte function. CONCLUSIONS: We expanded the phenotype of FRMD5-related disease and shed light on its role in brain function and development. We recommend including FRMD5 in the genetic workup of childhood-onset ataxia and nystagmus. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

2.
Brain ; 146(1): 65-74, 2023 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-36347471

RESUMEN

Parkinson's disease is a complex neurodegenerative disorder with a strong genetic component, for which most known disease-associated variants are single nucleotide polymorphisms (SNPs) and small insertions and deletions (indels). DNA repetitive elements account for >50% of the human genome; however, little is known of their contribution to Parkinson's disease aetiology. While select short tandem repeats (STRs) within candidate genes have been studied in Parkinson's disease, their genome-wide contribution remains unknown. Here we present the first genome-wide association study of STRs in Parkinson's disease. Through a meta-analysis of 16 imputed genome-wide association study cohorts from the International Parkinson's Disease Genomic Consortium (IPDGC), totalling 39 087 individuals (16 642 cases and 22 445 controls of European ancestry), we identified 34 genome-wide significant STR loci (P < 5.34 × 10-6), with the strongest signal located in KANSL1 [chr17:44 205 351:[T]11, P = 3 × 10-39, odds ratio = 1.31 (95% confidence interval = 1.26-1.36)]. Conditional-joint analyses suggested that four significant STRs mapping nearby NDUFAF2, TRIML2, MIRNA-129-1 and NCOR1 were independent from known risk SNPs. Including STRs in heritability estimates increased the variance explained by SNPs alone. Gene expression analysis of STRs (eSTRs) in RNA sequencing data from 13 brain regions identified significant associations of STRs influencing the expression of multiple genes, including known Parkinson's disease genes. Further functional annotation of candidate STRs revealed that significant eSTRs within NUDFAF2 and ZSWIM7 overlap with regulatory features and are associated with change in the expression levels of nearby genes. Here, we show that STRs at known and novel candidate loci contribute to Parkinson's disease risk and have functional effects in disease-relevant tissues and pathways, supporting previously reported disease-associated genes and giving further evidence for their functional prioritization. These data represent a valuable resource for researchers currently dissecting Parkinson's disease risk loci.


Asunto(s)
MicroARNs , Enfermedad de Parkinson , Humanos , Enfermedad de Parkinson/genética , Estudio de Asociación del Genoma Completo , Factores de Riesgo , Genoma Humano , Polimorfismo de Nucleótido Simple/genética , Repeticiones de Microsatélite/genética , Predisposición Genética a la Enfermedad/genética , Proteínas Portadoras/genética
3.
Brain ; 146(7): 2730-2738, 2023 07 03.
Artículo en Inglés | MEDLINE | ID: mdl-36860166

RESUMEN

ATP5F1B is a subunit of the mitochondrial ATP synthase or complex V of the mitochondrial respiratory chain. Pathogenic variants in nuclear genes encoding assembly factors or structural subunits are associated with complex V deficiency, typically characterized by autosomal recessive inheritance and multisystem phenotypes. Movement disorders have been described in a subset of cases carrying autosomal dominant variants in structural subunits genes ATP5F1A and ATP5MC3. Here, we report the identification of two different ATP5F1B missense variants (c.1000A>C; p.Thr334Pro and c.1445T>C; p.Val482Ala) segregating with early-onset isolated dystonia in two families, both with autosomal dominant mode of inheritance and incomplete penetrance. Functional studies in mutant fibroblasts revealed no decrease of ATP5F1B protein amount but severe reduction of complex V activity and impaired mitochondrial membrane potential, suggesting a dominant-negative effect. In conclusion, our study describes a new candidate gene associated with isolated dystonia and confirms that heterozygous variants in genes encoding subunits of the mitochondrial ATP synthase may cause autosomal dominant isolated dystonia with incomplete penetrance, likely through a dominant-negative mechanism.


Asunto(s)
Distonía , Trastornos Distónicos , Humanos , Distonía/genética , Trastornos Distónicos/genética , ATPasas de Translocación de Protón Mitocondriales/genética , Mutación Missense , Linaje , Proteínas/genética
4.
Hum Mol Genet ; 30(1): 78-86, 2021 03 25.
Artículo en Inglés | MEDLINE | ID: mdl-33448283

RESUMEN

Biallelic Parkin (PRKN) mutations cause autosomal recessive Parkinson's disease (PD); however, the role of monoallelic PRKN mutations as a risk factor for PD remains unclear. We investigated the role of single heterozygous PRKN mutations in three large independent case-control cohorts totalling 10 858 PD cases and 8328 controls. Overall, after exclusion of biallelic carriers, single PRKN mutations were more common in PD than controls conferring a >1.5-fold increase in the risk of PD [P-value (P) = 0.035], with meta-analysis (19 574 PD cases and 468 488 controls) confirming increased risk [Odds ratio (OR) = 1.65, P = 3.69E-07]. Carriers were shown to have significantly younger ages at the onset compared with non-carriers (NeuroX: 56.4 vs. 61.4 years; exome: 38.5 vs. 43.1 years). Stratifying by mutation type, we provide preliminary evidence for a more pathogenic risk profile for single PRKN copy number variant (CNV) carriers compared with single nucleotide variant carriers. Studies that did not assess biallelic PRKN mutations or consist of predominantly early-onset cases may be biasing these estimates, and removal of these resulted in a loss of association (OR = 1.23, P = 0.614; n = 4). Importantly, when we looked for additional CNVs in 30% of PD cases with apparent monoallellic PRKN mutations, we found that 44% had biallelic mutations, suggesting that previous estimates may be influenced by cryptic biallelic mutation status. While this study supports the association of single PRKN mutations with PD, it highlights confounding effects; therefore, caution is needed when interpreting current risk estimates. Together, we demonstrate that comprehensive assessment of biallelic mutation status is essential when elucidating PD risk associated with monoallelic PRKN mutations.


Asunto(s)
Variaciones en el Número de Copia de ADN/genética , Predisposición Genética a la Enfermedad , Enfermedad de Parkinson/genética , Ubiquitina-Proteína Ligasas/genética , Femenino , Estudios de Asociación Genética , Heterocigoto , Humanos , Masculino , Persona de Mediana Edad , Mutación/genética , Enfermedad de Parkinson/patología , Polimorfismo de Nucleótido Simple/genética , Factores de Riesgo
5.
Mov Disord ; 38(2): 185-195, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36350228

RESUMEN

Neuromelanin-containing dopaminergic neurons in the substantia nigra pars compacta (SNpc) are the most vulnerable neurons in Parkinson's disease (PD). Recent work suggests that the accumulation of oxidized dopamine and neuromelanin mediate the convergence of mitochondrial and lysosomal dysfunction in patient-derived neurons. In addition, the expression of human tyrosinase in mouse SNpc led to the formation of neuromelanin resulting in the degeneration of nigral dopaminergic neurons, further highlighting the importance of neuromelanin in PD. The potential role of neuromelanin in PD pathogenesis has been supported by epidemiological observations, whereby individuals with lighter pigmentation or cutaneous malignant melanoma exhibit higher incidence of PD. Because neuromelanin and melanin share many functional characteristics and overlapping biosynthetic pathways, it has been postulated that genes involved in skin pigmentation and melanin formation may play a role in the susceptibility of vulnerable midbrain dopaminergic neurons to neurodegeneration. Here, we highlight potential mechanisms that may explain the link between skin pigmentation and PD, focusing on the role of skin pigmentation genes in the pathogenesis of PD. We also discuss the importance of genetic ancestry in assessing the contribution of pigmentation-related genes to risk of PD. © 2022 International Parkinson and Movement Disorder Society.


Asunto(s)
Enfermedad de Parkinson , Humanos , Ratones , Animales , Enfermedad de Parkinson/patología , Melaninas/metabolismo , Pigmentación de la Piel , Sustancia Negra/metabolismo , Neuronas Dopaminérgicas/metabolismo
6.
Ann Neurol ; 89(3): 485-497, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33236446

RESUMEN

OBJECTIVE: The study was undertaken to identify a monogenic cause of early onset, generalized dystonia. METHODS: Methods consisted of genome-wide linkage analysis, exome and Sanger sequencing, clinical neurological examination, brain magnetic resonance imaging, and protein expression studies in skin fibroblasts from patients. RESULTS: We identified a heterozygous variant, c.388G>A, p.Gly130Arg, in the eukaryotic translation initiation factor 2 alpha kinase 2 (EIF2AK2) gene, segregating with early onset isolated generalized dystonia in 5 patients of a Taiwanese family. EIF2AK2 sequencing in 191 unrelated patients with unexplained dystonia yielded 2 unrelated Caucasian patients with an identical heterozygous c.388G>A, p.Gly130Arg variant, occurring de novo in one case, another patient carrying a different heterozygous variant, c.413G>C, p.Gly138Ala, and one last patient, born from consanguineous parents, carrying a third, homozygous variant c.95A>C, p.Asn32Thr. These 3 missense variants are absent from gnomAD, and are located in functional domains of the encoded protein. In 3 patients, additional neurological manifestations were present, including intellectual disability and spasticity. EIF2AK2 encodes a kinase (protein kinase R [PKR]) that phosphorylates eukaryotic translation initiation factor 2 alpha (eIF2α), which orchestrates the cellular stress response. Our expression studies showed abnormally enhanced activation of the cellular stress response, monitored by PKR-mediated phosphorylation of eIF2α, in fibroblasts from patients with EIF2AK2 variants. Intriguingly, PKR can also be regulated by PRKRA (protein interferon-inducible double-stranded RNA-dependent protein kinase activator A), the product of another gene causing monogenic dystonia. INTERPRETATION: We identified EIF2AK2 variants implicated in early onset generalized dystonia, which can be dominantly or recessively inherited, or occur de novo. Our findings provide direct evidence for a key role of a dysfunctional eIF2α pathway in the pathogenesis of dystonia. ANN NEUROL 2021;89:485-497.


Asunto(s)
Trastornos Distónicos/genética , Fibroblastos/metabolismo , eIF-2 Quinasa/genética , Adolescente , Adulto , Edad de Inicio , Pueblo Asiatico , Encéfalo/diagnóstico por imagen , Niño , Preescolar , Trastornos Distónicos/metabolismo , Trastornos Distónicos/fisiopatología , Femenino , Estudio de Asociación del Genoma Completo , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Mutación Missense , Linaje , Población Blanca , Secuenciación del Exoma , Adulto Joven , eIF-2 Quinasa/metabolismo
7.
Ann Neurol ; 89(4): 828-833, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33443317

RESUMEN

The Mediator multiprotein complex functions as a regulator of RNA polymerase II-catalyzed gene transcription. In this study, exome sequencing detected biallelic putative disease-causing variants in MED27, encoding Mediator complex subunit 27, in 16 patients from 11 families with a novel neurodevelopmental syndrome. Patient phenotypes are highly homogeneous, including global developmental delay, intellectual disability, axial hypotonia with distal spasticity, dystonic movements, and cerebellar hypoplasia. Seizures and cataracts were noted in severely affected individuals. Identification of multiple patients with biallelic MED27 variants supports the critical role of MED27 in normal human neural development, particularly for the cerebellum. ANN NEUROL 2021;89:828-833.


Asunto(s)
Cerebelo/anomalías , Discapacidades del Desarrollo/genética , Distonía/genética , Complejo Mediador/genética , Malformaciones del Sistema Nervioso/genética , Adolescente , Adulto , Secuencia de Aminoácidos , Catarata/genética , Niño , Preescolar , Epilepsia/genética , Variación Genética , Humanos , Lactante , Fenotipo , Secuenciación del Exoma
8.
Mov Disord ; 37(1): 137-147, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34596301

RESUMEN

BACKGROUND: Monogenic causes of isolated dystonia are heterogeneous. Assembling cohorts of affected individuals sufficiently large to establish new gene-disease relationships can be challenging. OBJECTIVE: We sought to expand the catalogue of monogenic etiologies for isolated dystonia. METHODS: After the discovery of a candidate variant in a multicenter exome-sequenced cohort of affected individuals with dystonia, we queried online platforms and genomic data repositories worldwide to identify subjects with matching genotypic profiles. RESULTS: Seven different biallelic loss-of-function variants in AOPEP were detected in five probands from four unrelated families with strongly overlapping phenotypes. In one proband, we observed a homozygous nonsense variant (c.1477C>T [p.Arg493*]). A second proband harbored compound heterozygous nonsense variants (c.763C>T [p.Arg255*]; c.777G>A [p.Trp259*]), whereas a third proband possessed a frameshift variant (c.696_697delAG [p.Ala234Serfs*5]) in trans with a splice-disrupting alteration (c.2041-1G>A). Two probands (siblings) from a fourth family shared compound heterozygous frameshift alleles (c.1215delT [p.Val406Cysfs*14]; c.1744delA [p.Met582Cysfs*6]). All variants were rare and expected to result in truncated proteins devoid of functionally important amino acid sequence. AOPEP, widely expressed in developing and adult human brain, encodes a zinc-dependent aminopeptidase, a member of a class of proteolytic enzymes implicated in synaptogenesis and neural maintenance. The probands presented with disabling progressive dystonia predominantly affecting upper and lower extremities, with variable involvement of craniocervical muscles. Dystonia was unaccompanied by any additional symptoms in three families, whereas the fourth family presented co-occurring late-onset parkinsonism. CONCLUSIONS: Our findings suggest a likely causative role of predicted inactivating biallelic AOPEP variants in cases of autosomal recessive dystonia. Additional studies are warranted to understand the pathophysiology associated with loss-of-function variation in AOPEP. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.


Asunto(s)
Aminopeptidasas , Distonía , Trastornos Distónicos , Mutación con Pérdida de Función , Aminopeptidasas/genética , Distonía/genética , Trastornos Distónicos/genética , Exoma , Humanos , Mutación , Linaje , Fenotipo
9.
Ann Neurol ; 88(5): 867-877, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32808683

RESUMEN

OBJECTIVES: The majority of people with suspected genetic dystonia remain undiagnosed after maximal investigation, implying that a number of causative genes have not yet been recognized. We aimed to investigate this paucity of diagnoses. METHODS: We undertook weighted burden analysis of whole-exome sequencing (WES) data from 138 individuals with unresolved generalized dystonia of suspected genetic etiology, followed by additional case-finding from international databases, first for the gene implicated by the burden analysis (VPS16), and then for other functionally related genes. Electron microscopy was performed on patient-derived cells. RESULTS: Analysis revealed a significant burden for VPS16 (Fisher's exact test p value, 6.9 × 109 ). VPS16 encodes a subunit of the homotypic fusion and vacuole protein sorting (HOPS) complex, which plays a key role in autophagosome-lysosome fusion. A total of 18 individuals harboring heterozygous loss-of-function VPS16 variants, and one with a microdeletion, were identified. These individuals experienced early onset progressive dystonia with predominant cervical, bulbar, orofacial, and upper limb involvement. Some patients had a more complex phenotype with additional neuropsychiatric and/or developmental comorbidities. We also identified biallelic loss-of-function variants in VPS41, another HOPS-complex encoding gene, in an individual with infantile-onset generalized dystonia. Electron microscopy of patient-derived lymphocytes and fibroblasts from both patients with VPS16 and VPS41 showed vacuolar abnormalities suggestive of impaired lysosomal function. INTERPRETATION: Our study strongly supports a role for HOPS complex dysfunction in the pathogenesis of dystonia, although variants in different subunits display different phenotypic and inheritance characteristics. ANN NEUROL 2020;88:867-877.


Asunto(s)
Distonía/genética , Enfermedades por Almacenamiento Lisosomal/genética , Proteínas de Transporte Vesicular/genética , Adulto , Costo de Enfermedad , Distonía/patología , Exoma/genética , Femenino , Fibroblastos/patología , Predisposición Genética a la Enfermedad/genética , Variación Genética , Humanos , Enfermedades por Almacenamiento Lisosomal/patología , Masculino , Persona de Mediana Edad , Mutación/genética , Linaje
10.
Ann Neurol ; 83(6): 1089-1095, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29518281

RESUMEN

VPS13 protein family members VPS13A through VPS13C have been associated with various recessive movement disorders. We describe the first disease association of rare recessive VPS13D variants including frameshift, missense, and partial duplication mutations with a novel complex, hyperkinetic neurological disorder. The clinical features include developmental delay, a childhood onset movement disorder (chorea, dystonia, or tremor), and progressive spastic ataxia or paraparesis. Characteristic brain magnetic resonance imaging shows basal ganglia or diffuse white matter T2 hyperintensities as seen in Leigh syndrome and choreoacanthocytosis. Muscle biopsy in 1 case showed mitochondrial aggregates and lipidosis, suggesting mitochondrial dysfunction. These findings underline the importance of the VPS13 complex in neurological diseases and a possible role in mitochondrial function. Ann Neurol 2018;83:1089-1095.


Asunto(s)
Discapacidad Intelectual/genética , Trastornos del Movimiento/genética , Espasticidad Muscular/genética , Mutación/genética , Atrofia Óptica/genética , Proteínas/genética , Ataxias Espinocerebelosas/genética , Ganglios Basales/patología , Encéfalo/patología , Niño , Humanos , Enfermedad de Leigh/patología , Imagen por Resonancia Magnética/métodos , Espasticidad Muscular/patología , Linaje
12.
Mov Disord ; 34(10): 1516-1527, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31216378

RESUMEN

BACKGROUND: Childhood-onset dystonia is often genetically determined. Recently, KMT2B variants have been recognized as an important cause of childhood-onset dystonia. OBJECTIVE: To define the frequency of KMT2B mutations in a cohort of dystonic patients aged <18 years at onset, the associated clinical and radiological phenotype, and the natural history of disease. METHODS: Whole-exome sequencing or customized gene panels were used to screen a cohort of 65 patients who had previously tested negative for all other known dystonia-associated genes. RESULTS: We identified 14 patients (21.5%) carrying KMT2B variants, of which 1 was classified as a variant of unknown significance. We also identified 2 additional patients carrying pathogenic mutations in GNAO1 and ATM. Overall, we established a definitive genetic diagnosis in 23% of cases. We observed a spectrum of clinical manifestations in KMT2B variant carriers, ranging from generalized dystonia to short stature or intellectual disability alone, even within the same family. In 78.5% of cases, dystonia involved the lower limbs at onset, with later caudocranial generalization. Eight patients underwent pallidal DBS with a median decrease of Burke-Fahn-Marsden Dystonia Rating Scale-Motor score of 38.5% in the long term. We also report on 4 asymptomatic carriers, suggesting that some KMT2B mutations may be associated with incomplete disease penetrance. CONCLUSIONS: KMT2B mutations are frequent in childhood-onset dystonia and cause a complex neurodevelopmental syndrome, often featuring growth retardation and intellectual disability as additional phenotypic features. A dramatic and long-lasting response to DBS is characteristic of DYT-KMT2B dystonia. © 2019 International Parkinson and Movement Disorder Society.


Asunto(s)
Trastornos Distónicos/genética , N-Metiltransferasa de Histona-Lisina/genética , Adolescente , Adulto , Anciano , Niño , Estudios de Cohortes , Estimulación Encefálica Profunda/métodos , Femenino , Humanos , Discapacidad Intelectual/genética , Masculino , Persona de Mediana Edad , Mutación/genética , Fenotipo , Adulto Joven
13.
Hum Mol Genet ; 25(24): 5483-5489, 2016 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-27798102

RESUMEN

Oligogenic inheritance implies a role for several genetic factors in disease etiology. We studied oligogenic inheritance in Parkinson's (PD) by assessing the potential burden of additional rare variants in established Mendelian genes and/or GBA, in individuals with and without a primary pathogenic genetic cause in two large independent cohorts totaling 7,900 PD cases and 6,166 controls. An excess (≥30%) of cases with a recognised primary genetic cause had ≥1 additional rare variants in Mendelian PD genes, as compared with no known mutation PD cases (17%) and unaffected controls (16%), supporting our hypothesis. Carriers of additional Mendelian gene variants have younger ages at onset (AAO). The effect of additional Mendelian variants in LRRK2 G2019S mutation carriers, of which ATP13A2 variation is particularly common, may account for some of the variation in penetrance. About 10% of No Known Mutation-PD cases harbour a rare GBA variant compared to known pathogenic mutation PD cases (8%) and controls (5%), with carriers having earlier AAOs. Together, the data suggest that the oligogenic inheritance of rare Mendelian variants may be important in patient with a primary pathogenic cause, whereas GBA increases risk across all forms of PD. This study highlights the potential genetic complexity of Mendelian PD. The identification of potential modifying variants provides new insights into disease mechanisms by potentially separating relevant from benign variants and by the interaction between genes in specific pathways. In the future this may be relevant to genetic testing and counselling of patients with PD and their families.


Asunto(s)
Predisposición Genética a la Enfermedad , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/genética , Herencia Multifactorial/genética , Enfermedad de Parkinson/genética , Edad de Inicio , Femenino , Genotipo , Humanos , Masculino , Mutación , Enfermedad de Parkinson/patología , Factores de Riesgo
14.
BMC Neurol ; 17(1): 153, 2017 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-28789629

RESUMEN

BACKGROUND: Bi-allelic mutations in the genes Parkin (PARK2), PINK1 (PARK6) and DJ-1 (PARK7) are established causes of autosomal recessive early-onset Parkinson's Disease (EOPD). PINK1 mutations are the second commonest cause of EOPD. Specific mutations may be relatively common in certain populations because of a founder effect. Homozygous p.A217D PINK1 mutations were previously shown to cause EOPD in a large Sudanese kindred. CASE PRESENTATION: Here we report the segregation of homozygous PINK1 p.A217D mutations in a family originating in Morocco with a history of parental consanguinity. From the clinical information available for the index case, the phenotype of mild, slowly-progressive Parkinsonism is consistent with previous reports of p.A217D disease and of PINK1 disease phenotype more generally. The reported features of early prominent lower-limb symptoms and gait disturbance with asymmetrical onset are more frequent among PINK1 disease cases. CONCLUSIONS: Together, reports of p.A217D in families of Moroccan and Sudanese origin suggest that p.A217D is a North African mutation due to a founder effect. Wider genetic analyses of EOPD in North Africa would be useful to estimate the prevalence of Parkinsonism caused by PINK1 p.A217D. In the absence of bi-allelic Parkin mutations, PINK1 mutations should be considered in cases with evidence of autosomal recessive inheritance of EOPD and presentation of atypical features such as early lower-limb symptoms and gait disturbance with asymmetrical onset, which appear to be common in Mendelian EOPD.


Asunto(s)
Trastornos Parkinsonianos/genética , Proteínas Quinasas/genética , Edad de Inicio , Análisis Mutacional de ADN , Femenino , Homocigoto , Humanos , Masculino , Marruecos , Mutación , Fenotipo , Ubiquitina-Proteína Ligasas/genética
17.
Brain ; 137(Pt 9): 2480-92, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24993959

RESUMEN

GTP cyclohydrolase 1, encoded by the GCH1 gene, is an essential enzyme for dopamine production in nigrostriatal cells. Loss-of-function mutations in GCH1 result in severe reduction of dopamine synthesis in nigrostriatal cells and are the most common cause of DOPA-responsive dystonia, a rare disease that classically presents in childhood with generalized dystonia and a dramatic long-lasting response to levodopa. We describe clinical, genetic and nigrostriatal dopaminergic imaging ([(123)I]N-ω-fluoropropyl-2ß-carbomethoxy-3ß-(4-iodophenyl) tropane single photon computed tomography) findings of four unrelated pedigrees with DOPA-responsive dystonia in which pathogenic GCH1 variants were identified in family members with adult-onset parkinsonism. Dopamine transporter imaging was abnormal in all parkinsonian patients, indicating Parkinson's disease-like nigrostriatal dopaminergic denervation. We subsequently explored the possibility that pathogenic GCH1 variants could contribute to the risk of developing Parkinson's disease, even in the absence of a family history for DOPA-responsive dystonia. The frequency of GCH1 variants was evaluated in whole-exome sequencing data of 1318 cases with Parkinson's disease and 5935 control subjects. Combining cases and controls, we identified a total of 11 different heterozygous GCH1 variants, all at low frequency. This list includes four pathogenic variants previously associated with DOPA-responsive dystonia (Q110X, V204I, K224R and M230I) and seven of undetermined clinical relevance (Q110E, T112A, A120S, D134G, I154V, R198Q and G217V). The frequency of GCH1 variants was significantly higher (Fisher's exact test P-value 0.0001) in cases (10/1318 = 0.75%) than in controls (6/5935 = 0.1%; odds ratio 7.5; 95% confidence interval 2.4-25.3). Our results show that rare GCH1 variants are associated with an increased risk for Parkinson's disease. These findings expand the clinical and biological relevance of GTP cycloydrolase 1 deficiency, suggesting that it not only leads to biochemical striatal dopamine depletion and DOPA-responsive dystonia, but also predisposes to nigrostriatal cell loss. Further insight into GCH1-associated pathogenetic mechanisms will shed light on the role of dopamine metabolism in nigral degeneration and Parkinson's disease.


Asunto(s)
GTP Ciclohidrolasa/genética , Heterocigoto , Mutación/genética , Enfermedad de Parkinson/diagnóstico , Enfermedad de Parkinson/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Bases de Datos Genéticas , Europa (Continente)/epidemiología , Femenino , Variación Genética , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/epidemiología , Linaje , Riesgo , Estados Unidos/epidemiología , Adulto Joven
18.
Neuron ; 2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38761794

RESUMEN

Neurodegenerative diseases are commonly classified as proteinopathies that are defined by the aggregation of a specific protein. Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are classified as synucleinopathies since α-synuclein (α-syn)-containing inclusions histopathologically define these diseases. Unbiased biochemical analysis of PD and DLB patient material unexpectedly revealed novel pathological inclusions in the nucleus comprising adenosine-to-inosine (A-to-I)-edited mRNAs and NONO and SFPQ proteins. These inclusions showed no colocalization with Lewy bodies and accumulated at levels comparable to α-syn. NONO and SFPQ aggregates reduced the expression of the editing inhibitor ADAR3, increasing A-to-I editing mainly within human-specific, Alu-repeat regions of axon, synaptic, and mitochondrial transcripts. Inosine-containing transcripts aberrantly accumulated in the nucleus, bound tighter to recombinant purified SFPQ in vitro, and potentiated SFPQ aggregation in human dopamine neurons, resulting in a self-propagating pathological state. Our data offer new insight into the inclusion composition and pathophysiology of PD and DLB.

19.
medRxiv ; 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-37292720

RESUMEN

Objective: To identify genetic factors that may modify the effects of the MAPT locus in Parkinson's disease (PD). Methods: We used data from the International Parkinson's Disease Genomics Consortium (IPDGC) and the UK biobank (UKBB). We stratified the IPDGC cohort for carriers of the H1/H1 genotype (PD patients n=8,492 and controls n=6,765) and carriers of the H2 haplotype (with either H1/H2 or H2/H2 genotypes, patients n=4,779 and controls n=4,849) to perform genome-wide association studies (GWASs). Then, we performed replication analyses in the UKBB data. To study the association of rare variants in the new nominated genes, we performed burden analyses in two cohorts (Accelerating Medicines Partnership - Parkinson Disease and UKBB) with a total sample size PD patients n=2,943 and controls n=18,486. Results: We identified a novel locus associated with PD among MAPT H1/H1 carriers near EMP1 (rs56312722, OR=0.88, 95%CI= 0.84-0.92, p= 1.80E-08), and a novel locus associated with PD among MAPT H2 carriers near VANGL1 (rs11590278, OR=1.69 95%CI=1.40-2.03, p=2.72E-08). Similar analysis of the UKBB data did not replicate these results and rs11590278 near VANGL1 did have similar effect size and direction in carriers of H2 haplotype, albeit not statistically significant (OR= 1.32, 95%CI= 0.94-1.86, p=0.17). Rare EMP1 variants with high CADD scores were associated with PD in the MAPT H2 stratified analysis (p=9.46E-05), mainly driven by the p.V11G variant. Interpretation: We identified several loci potentially associated with PD stratified by MAPT haplotype and larger replication studies are required to confirm these associations.

20.
medRxiv ; 2023 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-37986980

RESUMEN

Genome-wide genotyping platforms have the capacity to capture genetic variation across different populations, but there have been disparities in the representation of population-dependent genetic diversity. The motivation for pursuing this endeavor was to create a comprehensive genome-wide array capable of encompassing a wide range of neuro-specific content for the Global Parkinson's Genetics Program (GP2) and the Center for Alzheimer's and Related Dementias (CARD). CARD aims to increase diversity in genetic studies, using this array as a tool to foster inclusivity. GP2 is the first supported resource project of the Aligning Science Across Parkinson's (ASAP) initiative that aims to support a collaborative global effort aimed at significantly accelerating the discovery of genetic factors contributing to Parkinson's disease and atypical parkinsonism by generating genome-wide data for over 200,000 individuals in a multi-ancestry context. Here, we present the Illumina NeuroBooster array (NBA), a novel, high-throughput and cost-effective custom-designed content platform to screen for genetic variation in neurological disorders across diverse populations. The NBA contains a backbone of 1,914,934 variants (Infinium Global Diversity Array) complemented with custom content of 95,273 variants implicated in over 70 neurological conditions or traits with potential neurological complications. Furthermore, the platform includes over 10,000 tagging variants to facilitate imputation and analyses of neurodegenerative disease-related GWAS loci across diverse populations. The NBA can identify low frequency variants and accurately impute over 15 million common variants from the latest release of the TOPMed Imputation Server as of August 2023 (reference of over 300 million variants and 90,000 participants). We envisage this valuable tool will standardize genetic studies in neurological disorders across different ancestral groups, allowing researchers to perform genetic research inclusively and at a global scale.

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