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1.
Mov Disord ; 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31922365

RESUMO

BACKGROUND: The group of dystonia genes is expanding, and mutations of these genes have been associated with various combined dystonia syndromes. Among the latter, the cause of some dystonia parkinsonism cases remains unknown. OBJECTIVE: To report patients with early-onset dystonia parkinsonism as a result of loss-of-function mutations in nuclear receptor subfamily 4 group A member 2. METHODS: Phenotypic characterization and exome sequencing were carried out in 2 families. RESULTS: The 2 patients reported here both had a history of mild intellectual disability in childhood and subsequently developed dystonia parkinsonism in early adulthood. Brain magnetic resonance imaging was normal, and DATscan suggested bilateral dopaminergic denervation. Two frameshift mutations in NR4A2 were identified: a de novo insertion (NM_006186.3; c.326dupA) in the first case and another small insertion (NM_006186.3; c.881dupA) in the second. CONCLUSIONS: NR4A2 haploinsufficiency mutations have been recently reported in neurodevelopmental phenotypes. Our findings indicate that dystonia and/or parkinsonism may appear years after initial symptoms. Mutations in NR4A2 should be considered in patients with unexplained dystonia parkinsonism. © 2020 International Parkinson and Movement Disorder Society.

2.
Blood ; 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31826245

RESUMO

The rare PEL-negative phenotype is one of the last blood groups with an unknown genetic basis. By combining whole-exome sequencing and comparative global proteomic investigations, we found a large deletion in the ABCC4/MRP4 gene encoding an ATP-binding cassette (ABC) transporter in PEL-negative individuals. The loss of PEL expression on ABCC4-CRISPR-Cas9 K562 cells and its overexpression in ABCC4-transfected cells provided evidence that ABCC4 is the gene underlying the PEL blood group antigen. Although ABCC4 is an important cyclic nucleotide exporter, red blood cells from ABCC4null/PEL-negative individuals exhibited a normal cGMP level, suggesting a compensatory mechanism by other erythroid ABC transporters. Interestingly, PEL-negative individuals showed an impaired platelet aggregation, confirming a role for ABCC4 in platelet function. Finally, we showed that loss-of-function mutations in the ABCC4 gene, associated with leukemia outcome, altered the expression of the PEL antigen. Besides ABCC4 genotyping, PEL phenotyping could open a new way toward drug dose adjustment for leukemia treatment.

4.
J Clin Invest ; 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31613795

RESUMO

BACKGROUNDProteinuria is considered an unfavorable clinical condition that accelerates renal and cardiovascular disease. However, it is not clear whether all forms of proteinuria are damaging. Mutations in CUBN cause Imerslund-Gräsbeck syndrome (IGS), which is characterized by intestinal malabsorption of vitamin B12 and in some cases proteinuria. CUBN encodes for cubilin, an intestinal and proximal tubular uptake receptor containing 27 CUB domains for ligand binding.METHODSWe used next-generation sequencing for renal disease genes to genotype cohorts of patients with suspected hereditary renal disease and chronic proteinuria. CUBN variants were analyzed using bioinformatics, structural modeling, and epidemiological methods.RESULTSWe identified 39 patients, in whom biallelic pathogenic variants in the CUBN gene were associated with chronic isolated proteinuria and early childhood onset. Since the proteinuria in these patients had a high proportion of albuminuria, glomerular diseases such as steroid-resistant nephrotic syndrome or Alport syndrome were often the primary clinical diagnosis, motivating renal biopsies and the use of proteinuria-lowering treatments. However, renal function was normal in all cases. By contrast, we did not found any biallelic CUBN variants in proteinuric patients with reduced renal function or focal segmental glomerulosclerosis. Unlike the more N-terminal IGS mutations, 37 of the 41 proteinuria-associated CUBN variants led to modifications or truncations after the vitamin B12-binding domain. Finally, we show that 4 C-terminal CUBN variants are associated with albuminuria and slightly increased GFR in meta-analyses of large population-based cohorts.CONCLUSIONSCollectively, our data suggest an important role for the C-terminal half of cubilin in renal albumin reabsorption. Albuminuria due to reduced cubilin function could be an unexpectedly common benign condition in humans that may not require any proteinuria-lowering treatment or renal biopsy.FUNDINGATIP-Avenir program, Fondation Bettencourt-Schueller (Liliane Bettencourt Chair of Developmental Biology), Agence Nationale de la Recherche (ANR) Investissements d'avenir program (ANR-10-IAHU-01) and NEPHROFLY (ANR-14-ACHN-0013, to MS), Steno Collaborative Grant 2018 (NNF18OC0052457, to TSA and MS), Heisenberg Professorship of the German Research Foundation (KO 3598/5-1, to AK), Deutsche Forschungsgemeinschaft (DFG) Collaborative Research Centre (SFB) KIDGEM 1140 (project 246781735, to CB), and Federal Ministry of Education and Research (BMB) (01GM1515C, to CB).

5.
Blood ; 134(3): 277-290, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31151987

RESUMO

Shwachman-Diamond syndrome (SDS) is a recessive disorder typified by bone marrow failure and predisposition to hematological malignancies. SDS is predominantly caused by deficiency of the allosteric regulator Shwachman-Bodian-Diamond syndrome that cooperates with elongation factor-like GTPase 1 (EFL1) to catalyze release of the ribosome antiassociation factor eIF6 and activate translation. Here, we report biallelic mutations in EFL1 in 3 unrelated individuals with clinical features of SDS. Cellular defects in these individuals include impaired ribosomal subunit joining and attenuated global protein translation as a consequence of defective eIF6 eviction. In mice, Efl1 deficiency recapitulates key aspects of the SDS phenotype. By identifying biallelic EFL1 mutations in SDS, we define this leukemia predisposition disorder as a ribosomopathy that is caused by corruption of a fundamental, conserved mechanism, which licenses entry of the large ribosomal subunit into translation.

6.
Hum Mol Genet ; 28(16): 2720-2737, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31042281

RESUMO

Mutations in genes encoding components of the intraflagellar transport (IFT) complexes have previously been associated with a spectrum of diseases collectively termed ciliopathies. Ciliopathies relate to defects in the formation or function of the cilium, a sensory or motile organelle present on the surface of most cell types. IFT52 is a key component of the IFT-B complex and ensures the interaction of the two subcomplexes, IFT-B1 and IFT-B2. Here, we report novel IFT52 biallelic mutations in cases with a short-rib thoracic dysplasia (SRTD) or a congenital anomaly of kidney and urinary tract (CAKUT). Combining in vitro and in vivo studies in zebrafish, we showed that SRTD-associated missense mutation impairs IFT-B complex assembly and IFT-B2 ciliary localization, resulting in decreased cilia length. In comparison, CAKUT-associated missense mutation has a mild pathogenicity, thus explaining the lack of skeletal defects in CAKUT case. In parallel, we demonstrated that the previously reported homozygous nonsense IFT52 mutation associated with Sensenbrenner syndrome [Girisha et al. (2016) A homozygous nonsense variant in IFT52 is associated with a human skeletal ciliopathy. Clin. Genet., 90, 536-539] leads to exon skipping and results in a partially functional protein. Finally, our work uncovered a novel role for IFT52 in microtubule network regulation. We showed that IFT52 interacts and partially co-localized with centrin at the distal end of centrioles where it is involved in its recruitment and/or maintenance. Alteration of this function likely contributes to centriole splitting observed in Ift52-/- cells. Altogether, our findings allow a better comprehensive genotype-phenotype correlation among IFT52-related cases and revealed a novel, extra-ciliary role for IFT52, i.e. disruption may contribute to pathophysiological mechanisms.

7.
Am J Med Genet A ; 179(7): 1304-1309, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31004414

RESUMO

The spectrum of clinical consequences of variants in the Platelet derived growth factor receptor beta (PDGFRB) gene is wide. Missense variants leading to variable loss of signal transduction in vitro have been reported in the idiopathic basal ganglia calcification (IBGC) syndrome Type 4. In contrast, gain-of-function variants have been reported in infantile myofibromatosis, Penttinen syndrome, and Kosaki overgrowth syndrome. Here, we report a patient harboring a novel postzygotic variant in PDGFRB (c.1682_1684del, p.[Arg561_Tyr562delinsHis]) and presenting severe cerebral malformations, intracerebral calcifications, and infantile myofibromatosis. This observation expands the phenotype associated with PDGFRB variants and illustrates the wide clinical spectrum linked to dysregulation of PDGFRB.

8.
Nat Genet ; 51(1): 196, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30429576

RESUMO

In the version of this article originally published, the main-text sentence "In three patients of European ancestry, we identified the germline variant encoding p.Ile97Met in TIM-3, which was homozygous in two (P12 and P13) and heterozygous in one (P15) in the germline but with no TIM-3 plasma membrane expression in the tumor" misstated the identifiers of the two homozygous individuals, which should have been P13 and P14. The error has been corrected in the HTML, PDF and print versions of the paper.

9.
J Invest Dermatol ; 139(2): 380-390, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30321533

RESUMO

Investigation of genetic determinants of Mendelian skin disorders has substantially advanced understanding of epidermal biology. Here we show that mutations in PERP, encoding a crucial component of desmosomes, cause both dominant and recessive human keratoderma. Heterozygosity for a C-terminal truncation, which produces a protein that appears to be unstably incorporated into desmosomes, causes Olmsted syndrome with severe periorificial and palmoplantar keratoderma in multiple unrelated kindreds. Homozygosity for an N-terminal truncation ablates expression and causes widespread erythrokeratoderma, with expansion of epidermal differentiation markers. Both exhibit epidermal hyperproliferation, immature desmosomes lacking a dense midline observed via electron microscopy, and impaired intercellular adhesion upon mechanical stress. Localization of other desmosomal components appears normal, which is in contrast to other conditions caused by mutations in genes encoding desmosomal proteins. These discoveries highlight the essential role of PERP in human desmosomes and epidermal homeostasis and further expand the heterogeneous spectrum of inherited keratinization disorders.

10.
EMBO Mol Med ; 10(12)2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30446499

RESUMO

The genetic causes of congenital hypothyroidism due to thyroid dysgenesis (TD) remain largely unknown. We identified three novel TUBB1 gene mutations that co-segregated with TD in three distinct families leading to 1.1% of TUBB1 mutations in TD study cohort. TUBB1 (Tubulin, Beta 1 Class VI) encodes for a member of the ß-tubulin protein family. TUBB1 gene is expressed in the developing and adult thyroid in humans and mice. All three TUBB1 mutations lead to non-functional α/ß-tubulin dimers that cannot be incorporated into microtubules. In mice, Tubb1 knock-out disrupted microtubule integrity by preventing ß1-tubulin incorporation and impaired thyroid migration and thyroid hormone secretion. In addition, TUBB1 mutations caused the formation of macroplatelets and hyperaggregation of human platelets after stimulation by low doses of agonists. Our data highlight unexpected roles for ß1-tubulin in thyroid development and in platelet physiology. Finally, these findings expand the spectrum of the rare paediatric diseases related to mutations in tubulin-coding genes and provide new insights into the genetic background and mechanisms involved in congenital hypothyroidism and thyroid dysgenesis.


Assuntos
Plaquetas/citologia , Plaquetas/patologia , Mutação , Agregação Plaquetária , Disgenesia da Tireoide/genética , Tubulina (Proteína)/genética , Animais , Humanos , Camundongos , Camundongos Knockout , Disgenesia da Tireoide/patologia
12.
Nat Genet ; 50(12): 1650-1657, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30374066

RESUMO

Subcutaneous panniculitis-like T cell lymphoma (SPTCL), a non-Hodgkin lymphoma, can be associated with hemophagocytic lymphohistiocytosis (HLH), a life-threatening immune activation that adversely affects survival1,2. T cell immunoglobulin mucin 3 (TIM-3) is a modulator of immune responses expressed on subgroups of T and innate immune cells. We identify in ~60% of SPTCL cases germline, loss-of-function, missense variants altering highly conserved residues of TIM-3, c.245A>G (p.Tyr82Cys) and c.291A>G (p.Ile97Met), each with specific geographic distribution. The variant encoding p.Tyr82Cys TIM-3 occurs on a potential founder chromosome in patients with East Asian and Polynesian ancestry, while p.Ile97Met TIM-3 occurs in patients with European ancestry. Both variants induce protein misfolding and abrogate TIM-3's plasma membrane expression, leading to persistent immune activation and increased production of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1ß, promoting HLH and SPTCL. Our findings highlight HLH-SPTCL as a new genetic entity and identify mutations causing TIM-3 alterations as a causative genetic defect in SPTCL. While HLH-SPTCL patients with mutant TIM-3 benefit from immunomodulation, therapeutic repression of the TIM-3 checkpoint may have adverse consequences.


Assuntos
Mutação em Linhagem Germinativa , Receptor Celular 2 do Vírus da Hepatite A/genética , Linfo-Histiocitose Hemofagocítica/genética , Linfoma de Células T/genética , Paniculite/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Diagnóstico Diferencial , Feminino , Predisposição Genética para Doença , Humanos , Lactente , Linfo-Histiocitose Hemofagocítica/classificação , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfoma de Células T/classificação , Linfoma de Células T/diagnóstico , Masculino , Pessoa de Meia-Idade , Paniculite/classificação , Paniculite/diagnóstico , Linhagem , Sequenciamento Completo do Exoma , Adulto Jovem
13.
Eur J Med Genet ; 61(12): 755-758, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30121372

RESUMO

Autosomal recessive missense Rotatin (RTTN) mutations are responsible for syndromic forms of malformation of cortical development, ranging from isolated polymicrogyria to microcephaly associated with primordial dwarfism and other major malformations. We identified, by trio based whole exome sequencing, a homozygous missense mutation in the RTTN gene (c.2953A > G; p.(Arg985Gly)) in one Moroccan patient from a consanguineous family. The patient showed early onset primary microcephaly, detected in the fetal period, postnatal growth restriction, encephalopathy with hyperkinetic movement disorders and self-injurious behavior with sleep disturbance. Brain MRI showed an extensive dysgyria associated with nodular heterotopia, large interhemispheric arachnoid cyst and corpus callosum hypoplasia.


Assuntos
Proteínas de Transporte/genética , Nanismo/genética , Microcefalia/genética , Polimicrogiria/genética , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Proteínas de Ciclo Celular , Criança , Pré-Escolar , Consanguinidade , Bases de Dados Genéticas , Nanismo/diagnóstico por imagem , Nanismo/patologia , Feminino , Homozigoto , Humanos , Masculino , Microcefalia/diagnóstico por imagem , Microcefalia/patologia , Marrocos/epidemiologia , Mutação de Sentido Incorreto , Linhagem , Fenótipo , Polimicrogiria/diagnóstico por imagem , Polimicrogiria/patologia
14.
J Clin Immunol ; 38(5): 617-627, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29995221

RESUMO

PURPOSE: Inborn errors of IFN-γ immunity underlie Mendelian susceptibility to mycobacterial disease (MSMD). Autosomal recessive complete IL-12Rß1 deficiency is the most frequent genetic etiology of MSMD. Only two of the 84 known mutations are copy number variations (CNVs), identified in two of the 213 IL-12Rß1-deficient patients and two of the 164 kindreds reported. These two CNVs are large deletions found in the heterozygous or homozygous state. We searched for novel families with IL-12Rß1 deficiency due to CNVs. METHODS: We studied six MSMD patients from five unrelated kindreds displaying adverse reactions to BCG vaccination. Three of the patients also presented systemic salmonellosis, two had mucocutaneous candidiasis, and one had disseminated histoplasmosis. We searched for CNVs and other variations by IL12RB1-targeted next-generation sequencing (NGS). RESULTS: We identified six new IL-12Rß1-deficient patients with a complete loss of IL-12Rß1 expression on phytohemagglutinin-activated T cells and/or EBV-transformed B cells. The cells of these patients did not respond to IL-12 and IL-23. Five different CNVs encompassing IL12RB1 (four deletions and one duplication) were identified in these patients by NGS coverage analysis, either in the homozygous state (n = 1) or in trans (n = 4) with a single-nucleotide variation (n = 3) or a small indel (n = 1). Seven of the nine mutations are novel. Interestingly, four of the five CNVs were predicted to be driven by nearby Alu elements, as well as the two previously reported large deletions. The IL12RB1 locus is actually enriched in Alu elements (44.7%), when compared with the rest of the genome (10.5%). CONCLUSION: The IL12RB1 locus is Alu-enriched and therefore prone to rearrangements at various positions. CNVs should be considered in the genetic diagnosis of IL-12Rß1 deficiency.


Assuntos
Elementos Alu , Variações do Número de Cópias de DNA , Estudos de Associação Genética , Predisposição Genética para Doença , Subunidade beta 1 de Receptor de Interleucina-12/deficiência , Alelos , Sequência de Bases , Mapeamento Cromossômico , Feminino , Expressão Gênica , Humanos , Interferon gama , Masculino , Mutação , Infecções por Mycobacterium/diagnóstico , Infecções por Mycobacterium/etiologia , Infecções por Mycobacterium/metabolismo , Linhagem , Fenótipo
15.
Diabetes ; 67(9): 1816-1829, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29967002

RESUMO

Key requirements in type 1 diabetes (T1D) are in setting up new assays as diagnostic biomarkers that will apply to prediabetes, likely T-cell assays, and in designing antigen-specific therapies to prevent T1D development. New preclinical models of T1D will be required to help with advancing both aims. By crossing mouse strains that lack either murine MHC class I and class II genes and insulin genes, we developed YES mice that instead express human HLA-A*02:01, HLA-DQ8, and insulin genes as transgenes. The metabolic and immune phenotype of YES mice is basically identical to that of the parental strains. YES mice remain insulitis and diabetes free up to 1 year of follow-up, maintain normoglycemia to an intraperitoneal glucose challenge in the long-term range, have a normal ß-cell mass, and show normal immune responses to conventional antigens. This new model has been designed to evaluate adaptive immune responses to human insulin on a genetic background that recapitulates a human high-susceptibility HLA-DQ8 genetic background. Although insulitis free, YES mice develop T1D when challenged with polyinosinic-polycytidylic acid. They allow the characterization of preproinsulin epitopes recognized by CD8+ and CD4+ T cells upon immunization against human preproinsulin or during diabetes development.


Assuntos
Imunidade Adaptativa , Envelhecimento , Doenças Autoimunes/fisiopatologia , Diabetes Mellitus Tipo 1/fisiopatologia , Modelos Animais de Doenças , Ilhotas Pancreáticas/fisiopatologia , Estado Pré-Diabético/fisiopatologia , Imunidade Adaptativa/efeitos dos fármacos , Animais , Doenças Autoimunes/imunologia , Doenças Autoimunes/metabolismo , Doenças Autoimunes/patologia , Biomarcadores/sangue , Biomarcadores/metabolismo , Cruzamentos Genéticos , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patologia , Progressão da Doença , Feminino , Antígeno HLA-A2/genética , Antígeno HLA-A2/metabolismo , Antígenos HLA-DQ/sangue , Antígenos HLA-DQ/genética , Antígenos HLA-DQ/metabolismo , Humanos , Insulina/sangue , Insulina/genética , Insulina/metabolismo , Ilhotas Pancreáticas/imunologia , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos Transgênicos , Poli I-C/toxicidade , Estado Pré-Diabético/imunologia , Estado Pré-Diabético/metabolismo , Estado Pré-Diabético/patologia , Precursores de Proteínas/sangue , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Organismos Livres de Patógenos Específicos
16.
Mol Autism ; 9: 38, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29951184

RESUMO

Background: MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. miRNAs have emerged as important modulators of brain development and neuronal function and are implicated in several neurological diseases. Previous studies found miR-146a upregulation is the most common miRNA deregulation event in neurodevelopmental disorders such as autism spectrum disorder (ASD), epilepsy, and intellectual disability (ID). Yet, how miR-146a upregulation affects the developing fetal brain remains unclear. Methods: We analyzed the expression of miR-146a in the temporal lobe of ASD children using Taqman assay. To assess the role of miR-146a in early brain development, we generated and characterized stably induced H9 human neural stem cell (H9 hNSC) overexpressing miR-146a using various cell and molecular biology techniques. Results: We first showed that miR-146a upregulation occurs early during childhood in the ASD brain. In H9 hNSC, miR-146a overexpression enhances neurite outgrowth and branching and favors differentiation into neuronal like cells. Expression analyses revealed that 10% of the transcriptome was deregulated and organized into two modules critical for cell cycle control and neuronal differentiation. Twenty known or predicted targets of miR-146a were significantly deregulated in the modules, acting as potential drivers. The two modules also display distinct transcription profiles during human brain development, affecting regions relevant for ASD including the neocortex, amygdala, and hippocampus. Cell type analyses indicate markers for pyramidal, and interneurons are highly enriched in the deregulated gene list. Up to 40% of known markers of newly defined neuronal lineages were deregulated, suggesting that miR-146a could participate also in the acquisition of neuronal identities. Conclusion: Our results demonstrate the dynamic roles of miR-146a in early neuronal development and provide new insight into the molecular events that link miR-146a overexpression to impaired neurodevelopment. This, in turn, may yield new therapeutic targets and strategies.


Assuntos
Transtorno do Espectro Autista/genética , MicroRNAs/genética , Células-Tronco Neurais/metabolismo , Neurogênese , Transtorno do Espectro Autista/metabolismo , Linhagem Celular , Linhagem da Célula , Criança , Feminino , Humanos , Masculino , MicroRNAs/metabolismo , Células-Tronco Neurais/citologia , Lobo Temporal/citologia , Lobo Temporal/metabolismo , Regulação para Cima
17.
JAMA Neurol ; 75(10): 1234-1245, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29913018

RESUMO

Importance: Movement disorders are characterized by a marked genotypic and phenotypic heterogeneity, complicating diagnostic work in clinical practice and molecular diagnosis. Objective: To develop and evaluate a targeted sequencing approach using a customized panel of genes involved in movement disorders. Design, Setting and Participants: We selected 127 genes associated with movement disorders to create a customized enrichment in solution capture array. Targeted high-coverage sequencing was applied to DNA samples taken from 378 eligible patients at 1 Luxembourgian, 1 Algerian, and 25 French tertiary movement disorder centers between September 2014 and July 2016. Patients were suspected of having inherited movement disorders because of early onset, family history, and/or complex phenotypes. They were divided in 5 main movement disorder groups: parkinsonism, dystonia, chorea, paroxysmal movement disorder, and myoclonus. To compare approaches, 23 additional patients suspected of having inherited cerebellar ataxia were included, on whom whole-exome sequencing (WES) was done. Data analysis occurred from November 2015 to October 2016. Main Outcomes and Measures: Percentages of individuals with positive diagnosis, variants of unknown significance, and negative cases; mutational frequencies and clinical phenotyping of genes associated with movement disorders. Results: Of the 378 patients (of whom 208 were male [55.0%]), and with a median (range) age at disease onset of 31 (0-84) years, probable pathogenic variants were identified in 83 cases (22.0%): 46 patients with parkinsonism (55% of 83 patients), 21 patients (25.3%) with dystonia, 7 patients (8.4%) with chorea, 7 patients (8.4%) with paroxysmal movement disorders, and 2 patients (2.4%) with myoclonus as the predominant phenotype. Some genes were mutated in several cases in the cohort. Patients with pathogenic variants were significantly younger (median age, 27 years; interquartile range [IQR], 5-36 years]) than the patients without diagnosis (median age, 35 years; IQR, 15-46 years; P = .04). Diagnostic yield was significantly lower in patients with dystonia (21 of 135; 15.6%; P = .03) than in the overall cohort. Unexpected genotype-phenotype correlations in patients with pathogenic variants deviating from the classic phenotype were highlighted, and 49 novel probable pathogenic variants were identified. The WES analysis of the cohort of 23 patients with cerebellar ataxia led to an overall diagnostic yield of 26%, similar to panel analysis but at a cost 6 to 7 times greater. Conclusions and Relevance: High-coverage sequencing panel for the delineation of genes associated with movement disorders was efficient and provided a cost-effective diagnostic alternative to whole-exome and whole-genome sequencing.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Transtornos dos Movimentos/diagnóstico , Transtornos dos Movimentos/genética , Análise de Sequência de DNA/métodos , Sequenciamento Completo do Exoma/métodos , Adolescente , Adulto , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Ataxia Cerebelar/genética , Criança , Pré-Escolar , Coreia/diagnóstico , Coreia/genética , Distúrbios Distônicos/genética , Feminino , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala/economia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Mioclonia/diagnóstico , Mioclonia/genética , Transtornos Parkinsonianos/genética , Fenótipo , Estudos Prospectivos , Análise de Sequência de DNA/economia , Sequenciamento Completo do Exoma/economia , Adulto Jovem
18.
Brain ; 141(7): 1998-2013, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29878067

RESUMO

Cerebellar atrophy is a key neuroradiological finding usually associated with cerebellar ataxia and cognitive development defect in children. Unlike the adult forms, early onset cerebellar atrophies are classically described as mostly autosomal recessive conditions and the exact contribution of de novo mutations to this phenotype has not been assessed. In contrast, recent studies pinpoint the high prevalence of pathogenic de novo mutations in other developmental disorders such as intellectual disability, autism spectrum disorders and epilepsy. Here, we investigated a cohort of 47 patients with early onset cerebellar atrophy and/or hypoplasia using a custom gene panel as well as whole exome sequencing. De novo mutations were identified in 35% of patients while 27% had mutations inherited in an autosomal recessive manner. Understanding if these de novo events act through a loss or a gain of function effect is critical for treatment considerations. To gain a better insight into the disease mechanisms causing these cerebellar defects, we focused on CACNA1G, a gene not yet associated with the early-onset form. This gene encodes the Cav3.1 subunit of T-type calcium channels highly expressed in Purkinje neurons and deep cerebellar nuclei. We identified four patients with de novo CACNA1G mutations. They all display severe motor and cognitive impairment, cerebellar atrophy as well as variable features such as facial dysmorphisms, digital anomalies, microcephaly and epilepsy. Three subjects share a recurrent c.2881G>A/p.Ala961Thr variant while the fourth patient has the c.4591A>G/p.Met1531Val variant. Both mutations drastically impaired channel inactivation properties with significantly slower kinetics (∼5 times) and negatively shifted potential for half-inactivation (>10 mV). In addition, these two mutations increase neuronal firing in a cerebellar nuclear neuron model and promote a larger window current fully inhibited by TTA-P2, a selective T-type channel blocker. This study highlights the prevalence of de novo mutations in early-onset cerebellar atrophy and demonstrates that A961T and M1531V are gain of function mutations. Moreover, it reveals that aberrant activity of Cav3.1 channels can markedly alter brain development and suggests that this condition could be amenable to treatment.


Assuntos
Canais de Cálcio Tipo T/genética , Ataxia Cerebelar/genética , Adolescente , Adulto , Atrofia/patologia , Encéfalo/patologia , Cálcio/metabolismo , Canais de Cálcio/genética , Canais de Cálcio Tipo T/metabolismo , Ataxia Cerebelar/fisiopatologia , Doenças Cerebelares/complicações , Cerebelo/patologia , Criança , Pré-Escolar , Estudos de Coortes , Deficiências do Desenvolvimento/genética , Feminino , Mutação com Ganho de Função/genética , Humanos , Deficiência Intelectual/genética , Masculino , Microcefalia/genética , Mutação , Linhagem , Fenótipo , Células de Purkinje/patologia
19.
Eur J Med Genet ; 61(12): 729-732, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29758293

RESUMO

Postnatal microcephaly comprises a heterogeneous group of neurodevelopmental disorders of varying severity, characterized by normal head size at birth, followed by a postnatal deceleration in head circumference of greater than 3 standard deviations (SD) below the mean. Many postnatal microcephaly syndromes are caused by mutations in genes known to be important for the regulation of gene expression in the developing forebrain. We studied a consanguineous Pakistani family with postnatal microcephaly, orofacial dyskinesia, spastic quadriplegia and, on MRI, cortical atrophy with myelination delay, suggestive of a FOXG1-like presentation. Using trio-based exome sequencing, we identified a homozygous missense mutation in the Transducin-like enhancer of split-1 (TLE1) gene, encoding for a non DNA-binding transcriptional corepressor, highly expressed in the postnatal brain. The regulation of the post-mitotic neural survival activity of TLE1 depends critically on an interaction with FOXG1, a gene shown to be involved in a postnatal microcephaly syndrome. Functional analysis on affected dermal fibroblasts showed a significant decrease in mitotic and proliferative index, indicating a lengthening of the cell cycle and a delay in mitosis, supporting that this gene could be a new candidate for postnatal microcephaly.


Assuntos
Deficiência Intelectual/genética , Microcefalia/genética , Neurogênese/genética , Proteínas Repressoras/genética , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Criança , Pré-Escolar , Feminino , Fatores de Transcrição Forkhead/genética , Predisposição Genética para Doença , Humanos , Lactente , Deficiência Intelectual/diagnóstico por imagem , Imagem por Ressonância Magnética , Masculino , Microcefalia/diagnóstico por imagem , Microcefalia/patologia , Mutação , Proteínas do Tecido Nervoso/genética , Linhagem , Sequenciamento Completo do Exoma
20.
PLoS Genet ; 14(5): e1007386, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29768408

RESUMO

Recent evidence suggests that the presence of more than one pathogenic mutation in a single patient is more common than previously anticipated. One of the challenges hereby is to dissect the contribution of each gene mutation, for which animal models such as Drosophila can provide a valuable aid. Here, we identified three families with mutations in ADD3, encoding for adducin-γ, with intellectual disability, microcephaly, cataracts and skeletal defects. In one of the families with additional cardiomyopathy and steroid-resistant nephrotic syndrome (SRNS), we found a homozygous variant in KAT2B, encoding the lysine acetyltransferase 2B, with impact on KAT2B protein levels in patient fibroblasts, suggesting that this second mutation might contribute to the increased disease spectrum. In order to define the contribution of ADD3 and KAT2B mutations for the patient phenotype, we performed functional experiments in the Drosophila model. We found that both mutations were unable to fully rescue the viability of the respective null mutants of the Drosophila homologs, hts and Gcn5, suggesting that they are indeed pathogenic in flies. While the KAT2B/Gcn5 mutation additionally showed a significantly reduced ability to rescue morphological and functional defects of cardiomyocytes and nephrocytes (podocyte-like cells), this was not the case for the ADD3 mutant rescue. Yet, the simultaneous knockdown of KAT2B and ADD3 synergistically impaired kidney and heart function in flies as well as the adhesion and migration capacity of cultured human podocytes, indicating that mutations in both genes may be required for the full clinical manifestation. Altogether, our studies describe the expansion of the phenotypic spectrum in ADD3 deficiency associated with a homozygous likely pathogenic KAT2B variant and thereby identify KAT2B as a susceptibility gene for kidney and heart disease in ADD3-associated disorders.


Assuntos
Proteínas de Ligação a Calmodulina/genética , Drosophila/genética , Mutação , Fatores de Transcrição de p300-CBP/genética , Anormalidades Múltiplas/genética , Adolescente , Adulto , Animais , Proteínas de Ligação a Calmodulina/deficiência , Linhagem Celular , Células Cultivadas , Análise Mutacional de DNA , Proteínas de Drosophila/genética , Feminino , Cardiopatias/genética , Homozigoto , Humanos , Falência Renal Crônica/genética , Masculino , Linhagem , Fenótipo
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