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1.
Nat Commun ; 11(1): 5797, 2020 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-33199684

RESUMO

ARGONAUTE-2 and associated miRNAs form the RNA-induced silencing complex (RISC), which targets mRNAs for translational silencing and degradation as part of the RNA interference pathway. Despite the essential nature of this process for cellular function, there is little information on the role of RISC components in human development and organ function. We identify 13 heterozygous mutations in AGO2 in 21 patients affected by disturbances in neurological development. Each of the identified single amino acid mutations result in impaired shRNA-mediated silencing. We observe either impaired RISC formation or increased binding of AGO2 to mRNA targets as mutation specific functional consequences. The latter is supported by decreased phosphorylation of a C-terminal serine cluster involved in mRNA target release, increased formation of dendritic P-bodies in neurons and global transcriptome alterations in patient-derived primary fibroblasts. Our data emphasize the importance of gene expression regulation through the dynamic AGO2-RNA association for human neuronal development.


Assuntos
Proteínas Argonauta/genética , Células Germinativas/metabolismo , Mutação/genética , Sistema Nervoso/crescimento & desenvolvimento , Sistema Nervoso/metabolismo , Interferência de RNA , Adolescente , Animais , Proteínas Argonauta/química , Criança , Pré-Escolar , Análise por Conglomerados , Dendritos/metabolismo , Fibroblastos/metabolismo , Inativação Gênica , Células HEK293 , Hipocampo/patologia , Humanos , Camundongos , Simulação de Dinâmica Molecular , Neurônios/metabolismo , Fosforilação , Domínios Proteicos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Complexo de Inativação Induzido por RNA/metabolismo , Ratos , Transcriptoma/genética
2.
Nat Commun ; 11(1): 4589, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917887

RESUMO

Mandibuloacral dysplasia syndromes are mainly due to recessive LMNA or ZMPSTE24 mutations, with cardinal nuclear morphological abnormalities and dysfunction. We report five homozygous null mutations in MTX2, encoding Metaxin-2 (MTX2), an outer mitochondrial membrane protein, in patients presenting with a severe laminopathy-like mandibuloacral dysplasia characterized by growth retardation, bone resorption, arterial calcification, renal glomerulosclerosis and severe hypertension. Loss of MTX2 in patients' primary fibroblasts leads to loss of Metaxin-1 (MTX1) and mitochondrial dysfunction, including network fragmentation and oxidative phosphorylation impairment. Furthermore, patients' fibroblasts are resistant to induced apoptosis, leading to increased cell senescence and mitophagy and reduced proliferation. Interestingly, secondary nuclear morphological defects are observed in both MTX2-mutant fibroblasts and mtx-2-depleted C. elegans. We thus report the identification of a severe premature aging syndrome revealing an unsuspected link between mitochondrial composition and function and nuclear morphology, establishing a pathophysiological link with premature aging laminopathies and likely explaining common clinical features.


Assuntos
Acro-Osteólise/metabolismo , Predisposição Genética para Doença/genética , Lipodistrofia/metabolismo , Mandíbula/anormalidades , Proteínas de Membrana/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Acro-Osteólise/diagnóstico por imagem , Acro-Osteólise/genética , Acro-Osteólise/patologia , Senilidade Prematura/genética , Senilidade Prematura/metabolismo , Animais , Apoptose , Caenorhabditis elegans , Proliferação de Células , Criança , Regulação para Baixo , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Regulação da Expressão Gênica , Genótipo , Homozigoto , Humanos , Lipodistrofia/diagnóstico por imagem , Lipodistrofia/genética , Lipodistrofia/patologia , Masculino , Mandíbula/diagnóstico por imagem , Proteínas de Membrana/genética , Metaloendopeptidases , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas Mitocondriais/genética , Mutação , Fenótipo , Pele , Sequenciamento Completo do Genoma
3.
Genet Med ; 22(7): 1215-1226, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32376980

RESUMO

PURPOSE: Somatic variants in tumor necrosis factor receptor-associated factor 7 (TRAF7) cause meningioma, while germline variants have recently been identified in seven patients with developmental delay and cardiac, facial, and digital anomalies. We aimed to define the clinical and mutational spectrum associated with TRAF7 germline variants in a large series of patients, and to determine the molecular effects of the variants through transcriptomic analysis of patient fibroblasts. METHODS: We performed exome, targeted capture, and Sanger sequencing of patients with undiagnosed developmental disorders, in multiple independent diagnostic or research centers. Phenotypic and mutational comparisons were facilitated through data exchange platforms. Whole-transcriptome sequencing was performed on RNA from patient- and control-derived fibroblasts. RESULTS: We identified heterozygous missense variants in TRAF7 as the cause of a developmental delay-malformation syndrome in 45 patients. Major features include a recognizable facial gestalt (characterized in particular by blepharophimosis), short neck, pectus carinatum, digital deviations, and patent ductus arteriosus. Almost all variants occur in the WD40 repeats and most are recurrent. Several differentially expressed genes were identified in patient fibroblasts. CONCLUSION: We provide the first large-scale analysis of the clinical and mutational spectrum associated with the TRAF7 developmental syndrome, and we shed light on its molecular etiology through transcriptome studies.

4.
Biochem Soc Trans ; 48(3): 1199-1211, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32412080

RESUMO

Intellectual disability (ID) affects at least 1% of the population, and typically presents in the first few years of life. ID is characterized by impairments in cognition and adaptive behavior and is often accompanied by further delays in language and motor skills, as seen in many neurodevelopmental disorders (NDD). Recent widespread high-throughput approaches that utilize whole-exome sequencing or whole-genome sequencing have allowed for a considerable increase in the identification of these pathogenic variants in monogenic forms of ID. Notwithstanding this progress, the molecular and cellular consequences of the identified mutations remain mostly unknown. This is particularly important as the associated protein dysfunctions are the prerequisite to the identification of targets for novel drugs of these rare disorders. Recent Next-Generation sequencing-based studies have further established that mutations in genes encoding proteins involved in RNA metabolism are a major cause of NDD. Here, we review recent studies linking germline mutations in genes encoding factors mediating mRNA decay and regulators of translation, namely DCPS, EDC3, DDX6 helicase and ID. These RNA-binding proteins have well-established roles in mRNA decapping and/or translational repression, and the mutations abrogate their ability to remove 5' caps from mRNA, diminish their interactions with cofactors and stabilize sub-sets of transcripts. Additional genes encoding RNA helicases with roles in translation including DDX3X and DHX30 have also been linked to NDD. Given the speed in the acquisition, analysis and sharing of sequencing data, and the importance of post-transcriptional regulation for brain development, we anticipate mutations in more such factors being identified and functionally characterized.

5.
Artigo em Inglês | MEDLINE | ID: mdl-32065501

RESUMO

Both point mutations and deletions of the MYT1L gene as well as microdeletions of chromosome band 2p25.3 including MYT1L are associated with intellectual disability, obesity, and behavioral problems. Thus, MYT1L is assumed to be the-at least mainly-causative gene in the 2p25.3 deletion syndrome. Here, we present comprehensive descriptions of nine novel individuals bearing MYT1L mutations; most of them single nucleotide variants (SNVs). This increases the number of known individuals with causative deletions or SNVs of MYT1L to 51. Since eight of the nine novel patients bear mutations affecting MYT1L only, the total number of such individuals now nearly equals the number of individuals with larger microdeletions affecting additional genes, allowing for a comprehensive phenotypic comparison of these two patient groups. For example, 55% of the individuals with mutations affecting MYT1L only were overweight or obese as compared to 86% of the individuals with larger microdeletions. A similar trend was observed regarding short stature with 5 versus 35%, respectively. However, these differences were nominally significant only after correction for multiple testing, further supporting the hypothesis that MYT1L haploinsufficiency is central to the 2p25.3 deletion phenotype. Most importantly, the large number of individuals with MYT1L mutations presented and reviewed here allowed for the delineation of a more comprehensive clinical picture. Seizures, postnatal short stature, macrocephaly, and microcephaly could be shown to be over-represented among individuals with MYT1L mutations.

6.
Hum Genet ; 139(4): 483-498, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32055997

RESUMO

Biallelic variants in TOR1AIP1, encoding the integral nuclear membrane protein LAP1 (lamina-associated polypeptide 1) with two functional isoforms LAP1B and LAP1C, have initially been linked to muscular dystrophies with variable cardiac and neurological impairment. Furthermore, a recurrent homozygous nonsense alteration, resulting in loss of both LAP1 isoforms, was identified in seven likely related individuals affected by multisystem anomalies with progeroid-like appearance and lethality within the 1st decade of life. Here, we have identified compound heterozygosity in TOR1AIP1 affecting both LAP1 isoforms in two unrelated individuals affected by congenital bilateral hearing loss, ventricular septal defect, bilateral cataracts, mild to moderate developmental delay, microcephaly, mandibular hypoplasia, short stature, progressive muscular atrophy, joint contractures and severe chronic heart failure, with much longer survival. Cellular characterization of primary fibroblasts of one affected individual revealed absence of both LAP1B and LAP1C, constitutively low lamin A/C levels, aberrant nuclear morphology including nuclear cytoplasmic channels, and premature senescence, comparable to findings in other progeroid forms of nuclear envelopathies. We additionally observed an abnormal activation of the extracellular signal-regulated kinase 1/2 (ERK 1/2). Ectopic expression of wild-type TOR1AIP1 mitigated these cellular phenotypes, providing further evidence for the causal role of identified genetic variants. Altogether, we thus further expand the TOR1AIP1-associated phenotype by identifying individuals with biallelic loss-of-function variants who survived beyond the 1st decade of life and reveal novel molecular consequences underlying the TOR1AIP1-associated disorders.


Assuntos
Doenças Genéticas Inatas/genética , Proteínas de Choque Térmico HSC70/genética , Mutação com Perda de Função , Membrana Nuclear/genética , Adulto , Feminino , Humanos , Masculino , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/genética , Isoformas de Proteínas
7.
Brain ; 143(1): 55-68, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31834374

RESUMO

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3' region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.

8.
Dtsch Arztebl Int ; 116(29-30): 489-496, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31452499

RESUMO

BACKGROUND: Segmental progeroid syndromes (SPS) are rare hereditary diseases in which the affected individuals show signs of premature aging in more than one organ or type of tissue. We review the clinical and genetic features of some of these syndromes and discuss the extent to which their study affords a complementary opportunity to study aging processes in general. METHODS: This review is based on publications retrieved by a selective search in PubMed. RESULTS: Segmental progeroid syndromes are a clinically and genetically heterogeneous group of hereditary diseases. They can be categorized, for example, by the age of onset of manifestations (congenital vs. infantile vs. juvenile/adult forms). They are diagnosed on clinical grounds supplemented by genetic testing on the basis of next-generation sequencing, which is of central importance in view of the marked heterogeneity and complexity of their overlapping clinical features. The elucidation of the genetic and molecular causes of these diseases can lead to causally directed treatment, as shown by the initial clinical trials in Hutchinson- Gilford progeria syndrome. The molecular features of SPS are identical in many ways to those of "physiological" aging. Thus, studying the molecular mechanisms of SPS may be helpful for the development of molecularly defined treatment approaches for age-associated diseases in general. CONCLUSION: Segmental progeroid syndromes are a complex group of diseases with overlapping clinical features. Current research efforts focus on the elucidation of the molecular mechanisms of these diseases, most of which are very rare. This should enable the development of treatments that might be applicable to general processes of aging as well.

9.
Am J Hum Genet ; 105(2): 302-316, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31256877

RESUMO

Members of a paralogous gene family in which variation in one gene is known to cause disease are eight times more likely to also be associated with human disease. Recent studies have elucidated DHX30 and DDX3X as genes for which pathogenic variant alleles are involved in neurodevelopmental disorders. We hypothesized that variants in paralogous genes encoding members of the DExD/H-box RNA helicase superfamily might also underlie developmental delay and/or intellectual disability (DD and/or ID) disease phenotypes. Here we describe 15 unrelated individuals who have DD and/or ID, central nervous system (CNS) dysfunction, vertebral anomalies, and dysmorphic features and were found to have probably damaging variants in DExD/H-box RNA helicase genes. In addition, these individuals exhibit a variety of other tissue and organ system involvement including ocular, outer ear, hearing, cardiac, and kidney tissues. Five individuals with homozygous (one), compound-heterozygous (two), or de novo (two) missense variants in DHX37 were identified by exome sequencing. We identified ten total individuals with missense variants in three other DDX/DHX paralogs: DHX16 (four individuals), DDX54 (three individuals), and DHX34 (three individuals). Most identified variants are rare, predicted to be damaging, and occur at conserved amino acid residues. Taken together, these 15 individuals implicate the DExD/H-box helicases in both dominantly and recessively inherited neurodevelopmental phenotypes and highlight the potential for more than one disease mechanism underlying these disorders.


Assuntos
RNA Helicases DEAD-box/genética , Mutação de Sentido Incorreto , Proteínas de Neoplasias/genética , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/patologia , RNA Helicases/genética , Feminino , Estudos de Associação Genética , Humanos , Lactente , Recém-Nascido , Masculino , Linhagem , Sequenciamento Completo do Exoma
10.
Nat Commun ; 10(1): 3142, 2019 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-31316063

RESUMO

The SPRTN metalloprotease is essential for DNA-protein crosslink (DPC) repair and DNA replication in vertebrate cells. Cells deficient in SPRTN protease exhibit DPC-induced replication stress and genome instability, manifesting as premature ageing and liver cancer. Here, we provide a body of evidence suggesting that SPRTN activates the ATR-CHK1 phosphorylation signalling cascade during physiological DNA replication by proteolysis-dependent eviction of CHK1 from replicative chromatin. During this process, SPRTN proteolyses the C-terminal/inhibitory part of CHK1, liberating N-terminal CHK1 kinase active fragments. Simultaneously, CHK1 full length and its N-terminal fragments phosphorylate SPRTN at the C-terminal regulatory domain, which stimulates SPRTN recruitment to chromatin to promote unperturbed DNA replication fork progression and DPC repair. Our data suggest that a SPRTN-CHK1 cross-activation loop plays a part in DNA replication and protection from DNA replication stress. Finally, our results with purified components of this pathway further support the proposed model of a SPRTN-CHK1 cross-activation loop.


Assuntos
Quinase 1 do Ponto de Checagem/fisiologia , Proteínas de Ligação a DNA/fisiologia , Modelos Genéticos , Animais , Quinase 1 do Ponto de Checagem/metabolismo , Quebras de DNA , Replicação do DNA , Proteínas de Ligação a DNA/metabolismo , Instabilidade Genômica , Fosforilação , Transdução de Sinais , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
11.
Front Oncol ; 9: 420, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31192125

RESUMO

Unrecognized genome instability syndromes can potentially impede the rational treatment of cancer in rare patients. Identification of cancer patients with a hereditary condition is a compelling necessity for oncologists, giving varying hypersensitivities to various chemotherapeutic agents or radiation, depending on the underlying genetic cause. Omission of genetic testing in the setting of an overlooked hereditary syndrome may lead to unexpected and unbearable toxicity from oncological standard approaches. We present a case of a 33-year-old man with an early-onset stage IV intrahepatic cholangiocarcinoma, who experienced unusual bone marrow failure and neutropenic fever syndrome as a consequence of palliative chemotherapy containing cisplatin and gemcitabine, leading to a fatal outcome on day 25 of his first chemotherapeutic cycle. The constellation of bone marrow failure after exposure to the platinum-based agent cisplatin, the presence of an early-onset solid malignancy and the critical appraisal of further phenotypical features raised suspicion of a hereditary genome instability syndrome. Whole-exome sequencing from buccal swab DNA enabled the post mortem diagnosis of Fanconi anemia, most likely linked to the fatal outcome due to utilization of the DNA crosslinking agent cisplatin. The patient's phenotype was exceptional, as he never displayed significant hematologic abnormalities, which is the hallmark of Fanconi anemia. As such, this case stresses the importance to at least question the possibility of a hereditary basis in cases of relatively early-onset malignancy before defining an oncological treatment strategy.

12.
Dtsch Arztebl Int ; 116(12): 197-204, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-31056085

RESUMO

BACKGROUND: In developed countries, global developmental disorders are encounter- ed in approximately 1% of all children. The causes are manifold, and no exogenous cause can be identified in about half of the affected children. The parallel investi- gation of the coding sequences of all genes of the affected individual (whole exome sequencing, WES) has developed into a successful diagnostic method for identify- ing the cause of the problem. It is not yet clear, however, when WES should best be used in routine clinical practice in order to exploit the potential of this method to the fullest. METHODS: In an interdisciplinary study, we carried out standardized clinical pheno- typing and a systematic genetic analysis (WES of the index patient and his or her parents, so-called trio WES) in 50 children with developmental disturbances of unclear etiology and with nonspecific neurological manifestations. RESULTS: In 21 children (42% of the collective), we were able to identify the cause of the disorder by demonstrating a mutation in a gene known to be associated with disease. Three of these children subsequently underwent specific treatment. In 22 other children (44%), we detected possibly etiological changes in candidate genes not currently known to be associated with human disease. CONCLUSION: Our detection rate of at least 42% is high in comparison with the results obtained in other studies from Germany and other countries to date and implies that WES can be used to good effect as a differential diagnostic tool in pediatric neurol- ogy. WES should be carried out in both the index patient and his or her parents (trio- WES) and accompanied by close interdisciplinary collaboration of human geneti- cists and pediatricians, by comprehensive and targeted phenotyping (also after the diagnosis is established), and by the meticulous evaluation of all gene variants.


Assuntos
Sequenciamento Completo do Exoma , Criança , Alemanha , Humanos
13.
Am J Hum Genet ; 104(4): 749-757, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30905398

RESUMO

Over a relatively short period of time, the clinical geneticist's "toolbox" has been expanded by machine-learning algorithms for image analysis, which can be applied to the task of syndrome identification on the basis of facial photographs, but these technologies harbor potential beyond the recognition of established phenotypes. Here, we comprehensively characterized two individuals with a hitherto unknown genetic disorder caused by the same de novo mutation in LEMD2 (c.1436C>T;p.Ser479Phe), the gene which encodes the nuclear envelope protein LEM domain-containing protein 2 (LEMD2). Despite different ages and ethnic backgrounds, both individuals share a progeria-like facial phenotype and a distinct combination of physical and neurologic anomalies, such as growth retardation; hypoplastic jaws crowded with multiple supernumerary, yet unerupted, teeth; and cerebellar intention tremor. Immunofluorescence analyses of patient fibroblasts revealed mutation-induced disturbance of nuclear architecture, recapitulating previously published data in LEMD2-deficient cell lines, and additional experiments suggested mislocalization of mutant LEMD2 protein within the nuclear lamina. Computational analysis of facial features with two different deep neural networks showed phenotypic proximity to other nuclear envelopathies. One of the algorithms, when trained to recognize syndromic similarity (rather than specific syndromes) in an unsupervised approach, clustered both individuals closely together, providing hypothesis-free hints for a common genetic etiology. We show that a recurrent de novo mutation in LEMD2 causes a nuclear envelopathy whose prognosis in adolescence is relatively good in comparison to that of classical Hutchinson-Gilford progeria syndrome, and we suggest that the application of artificial intelligence to the analysis of patient images can facilitate the discovery of new genetic disorders.


Assuntos
Proteínas de Membrana/genética , Mutação , Proteínas Nucleares/genética , Progéria/genética , Adolescente , Inteligência Artificial , Linhagem Celular Tumoral , Núcleo Celular , Criança , Pré-Escolar , Diagnóstico por Computador , Face , Fibroblastos/metabolismo , Humanos , Masculino , Programas de Rastreamento/métodos , Informática Médica , Fenótipo , Prognóstico , Síndrome
14.
JAMA Oncol ; 5(4): 514-522, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30676620

RESUMO

Importance: Approximately 50% of the risk for the development of testicular germ cell tumors (TGCTs) is estimated to be heritable, but no mendelian TGCT predisposition genes have yet been identified. It is hypothesized that inherited pathogenic DNA repair gene (DRG) alterations may drive susceptibility to TGCTs. Objective: To systematically evaluate the enrichment of germline pathogenic variants in the mendelian cancer predisposition DRGs in patients with TGCTs vs healthy controls. Design, Setting, and Participants: A case-control enrichment analysis was performed from January 2016 to May 2018 to screen for 48 DRGs in 205 unselected men with TGCT and 27 173 ancestry-matched cancer-free individuals from the Exome Aggregation Consortium cohort in the discovery stage. Significant findings were selectively replicated in independent cohorts of 448 unselected men with TGCTs and 442 population-matched controls, as well as 231 high-risk men with TGCTs and 3090 ancestry-matched controls. Statistical analysis took place from January to May 2018. Main Outcomes and Measures: Gene-level enrichment analysis of germline pathogenic variants in individuals with TGCTs relative to cancer-free controls. Results: Among 205 unselected men with TGCTs (mean [SD] age, 33.04 [9.67] years), 22 pathogenic germline DRG variants, one-third of which were in CHEK2 (OMIM 604373), were identified in 20 men (9.8%; 95% CI, 6.1%-14.7%). Unselected men with TGCTs were approximately 4 times more likely to carry germline loss-of-function CHEK2 variants compared with cancer-free individuals from the Exome Aggregation Consortium cohort (odds ratio [OR], 3.87; 95% CI, 1.65-8.86; nominal P = .006; q = 0.018). Similar enrichment was also seen in an independent cohort of 448 unselected Croatian men with TGCTs (mean [SD] age, 31.98 [8.11] years) vs 442 unselected Croatian men without TGCTs (at least 50 years of age at time of sample collection) (OR, >1.4; P = .03) and 231 high-risk men with TGCTs (mean [SD] age, 31.54 [9.24] years) vs 3090 men (all older than 50 years) from the Penn Medicine Biobank (OR, 6.30; 95% CI, 2.34-17.31; P = .001). The low-penetrance CHEK2 variant (p.Ile157Thr) was found to be a Croatian founder TGCT risk variant (OR, 3.93; 95% CI, 1.53-9.95; P = .002). Individuals with the pathogenic CHEK2 loss-of-function variants developed TGCTs 6 years earlier than individuals with CHEK2 wild-type alleles (5.95 years; 95% CI, 1.48-10.42; P = .009). Conclusions and Relevance: This multicenter case-control analysis of men with or without TGCTs provides evidence for CHEK2 as a novel moderate-penetrance TGCT susceptibility gene, with potential clinical utility. In addition to highlighting DNA-repair deficiency as a potential mechanism driving TGCT susceptibility, this analysis also provides new avenues to explore management strategies and biological investigations for high-risk individuals.


Assuntos
Quinase do Ponto de Checagem 2/genética , Predisposição Genética para Doença , Neoplasias Embrionárias de Células Germinativas/genética , Neoplasias Testiculares/genética , Adulto , Estudos de Casos e Controles , Mutação em Linhagem Germinativa , Humanos , Masculino , Adulto Jovem
16.
Mol Genet Genomic Med ; 6(6): 1148-1156, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30393977

RESUMO

BACKGROUND: Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) is an autosomal recessive disorder caused by pathogenic variants of the conserved telomere maintenance component 1 (CTC1) gene. The CTC1 forms the telomeric capping complex, CST, which functions in telomere homeostasis and replication. METHODS: A Brazilian pedigree and an Australian pedigree were referred to the International Registry of Werner Syndrome (Seattle, WA, USA), with clinical features of accelerated aging and recurrent bone fractures. Whole exome sequencing was performed to identify the genetic causes. RESULTS: Whole exome sequencing of the Brazilian pedigree revealed compound heterozygous pathogenic variants in CTC1: a missense mutation (c.2959C>T, p.Arg987Trp) and a novel stop codon change (c.322C>T, p.Arg108*). The Australian patient carried two novel heterozygous CTC1 variants, c.2916G>T, p.Val972Gly and c.2926G>T, p.Val976Phe within the same allele. Both heterozygous variants were inherited from the unaffected father, excluding the diagnosis of CRMCC in this pedigree. Cell biological studies demonstrated accumulation of double strand break foci in lymphoblastoid cell lines derived from the patients. Increased DSB foci were extended to non-telomeric regions of the genome, in agreement with previous biochemical studies showing a preferential binding of CTC1 protein to GC-rich sequences. CONCLUSION: CTC1 pathogenic variants can present with unusual manifestations of progeria accompanied with recurrent bone fractures. Further studies are needed to elucidate the disease mechanism leading to the clinical presentation with intra-familial variations of CRMCC.


Assuntos
Fraturas Ósseas/genética , Mutação , Fenótipo , Proteínas de Ligação a Telômeros/genética , Síndrome de Werner/genética , Adulto , Linhagem Celular , Quebras de DNA de Cadeia Dupla , Feminino , Fraturas Ósseas/patologia , Sequência Rica em GC , Instabilidade Genômica , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Ligação Proteica , Telômero/genética , Proteínas de Ligação a Telômeros/metabolismo , Síndrome de Werner/patologia
17.
Hum Genet ; 137(11-12): 921-939, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30450527

RESUMO

Juvenile segmental progeroid syndromes are rare, heterogeneous disorders characterized by signs of premature aging affecting more than one tissue or organ starting in childhood. Hutchinson-Gilford progeria syndrome (HGPS), caused by a recurrent de novo synonymous LMNA mutation resulting in aberrant splicing and generation of a mutant product called progerin, is a prototypical example of such disorders. Here, we performed a joint collaborative study using massively parallel sequencing and targeted Sanger sequencing, aimed at delineating the underlying genetic cause of 14 previously undiagnosed, clinically heterogeneous, non-LMNA-associated juvenile progeroid patients. The molecular diagnosis was achieved in 11 of 14 cases (~ 79%). Furthermore, we firmly establish biallelic mutations in POLR3A as the genetic cause of a recognizable, neonatal, Wiedemann-Rautenstrauch-like progeroid syndrome. Thus, we suggest that POLR3A mutations are causal for a portion of under-diagnosed early-onset segmental progeroid syndromes. We additionally expand the clinical spectrum associated with PYCR1 mutations by showing that they can somewhat resemble HGPS in the first year of life. Moreover, our results lead to clinical reclassification in one single case. Our data emphasize the complex genetic and clinical heterogeneity underlying progeroid disorders.


Assuntos
Retardo do Crescimento Fetal/genética , Progéria/genética , Pirrolina Carboxilato Redutases/genética , RNA Polimerase III/genética , Adolescente , Processamento Alternativo/genética , Criança , Feminino , Retardo do Crescimento Fetal/diagnóstico , Retardo do Crescimento Fetal/patologia , Predisposição Genética para Doença , Humanos , Lactente , Lamina Tipo A/genética , Masculino , Mutação , Fenótipo , Progéria/diagnóstico , Progéria/patologia , Progéria/fisiopatologia
18.
Am J Hum Genet ; 103(4): 579-591, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30290153

RESUMO

p21-activated kinases (PAKs) are serine/threonine protein kinases acting as effectors of CDC42 and RAC, which are members of the RHO family of small GTPases. PAK1's kinase activity is autoinhibited by homodimerization, whereas CDC42 or RAC1 binding causes PAK1 activation by dimer dissociation. Major functions of the PAKs include actin cytoskeleton reorganization, for example regulation of the cellular protruding activity during cell spreading. We report the de novo PAK1 mutations c.392A>G (p.Tyr131Cys) and c.1286A>G (p.Tyr429Cys) in two unrelated subjects with developmental delay, secondary macrocephaly, seizures, and ataxic gait. We identified enhanced phosphorylation of the PAK1 targets JNK and AKT in fibroblasts of one subject and of c-JUN in those of both subjects compared with control subjects. In fibroblasts of the two affected individuals, we observed a trend toward enhanced PAK1 kinase activity. By using co-immunoprecipitation and size-exclusion chromatography, we observed a significantly reduced dimerization for both PAK1 mutants compared with wild-type PAK1. These data demonstrate that the two PAK1 variants function as activating alleles. In a cell spreading assay, subject-derived fibroblasts showed significant enrichment in cells occupied by filopodia. Interestingly, application of the PAK1 inhibitor FRAX486 completely reversed this cellular phenotype. Together, our data reveal that dominantly acting, gain-of-function PAK1 mutations cause a neurodevelopmental phenotype with increased head circumference, possibly by a combined effect of defective homodimerization and enhanced kinase activity of PAK1. This condition, along with the developmental disorders associated with RAC1 and CDC42 missense mutations, highlight the importance of RHO GTPase members and effectors in neuronal development.


Assuntos
Mutação com Ganho de Função/genética , Transtornos do Neurodesenvolvimento/genética , Quinases Ativadas por p21/genética , Actinas/genética , Estudos de Casos e Controles , Linhagem Celular , Criança , Pré-Escolar , Citoesqueleto/genética , Feminino , Células HEK293 , Humanos , Masculino , Miotonina Proteína Quinase/genética , Fosforilação/genética , Transdução de Sinais/genética , Proteínas rac1 de Ligação ao GTP/genética
19.
Brain ; 141(8): 2299-2311, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29985992

RESUMO

The transcription factor BCL11B is essential for development of the nervous and the immune system, and Bcl11b deficiency results in structural brain defects, reduced learning capacity, and impaired immune cell development in mice. However, the precise role of BCL11B in humans is largely unexplored, except for a single patient with a BCL11B missense mutation, affected by multisystem anomalies and profound immune deficiency. Using massively parallel sequencing we identified 13 patients bearing heterozygous germline alterations in BCL11B. Notably, all of them are affected by global developmental delay with speech impairment and intellectual disability; however, none displayed overt clinical signs of immune deficiency. Six frameshift mutations, two nonsense mutations, one missense mutation, and two chromosomal rearrangements resulting in diminished BCL11B expression, arose de novo. A further frameshift mutation was transmitted from a similarly affected mother. Interestingly, the most severely affected patient harbours a missense mutation within a zinc-finger domain of BCL11B, probably affecting the DNA-binding structural interface, similar to the recently published patient. Furthermore, the most C-terminally located premature termination codon mutation fails to rescue the progenitor cell proliferation defect in hippocampal slice cultures from Bcl11b-deficient mice. Concerning the role of BCL11B in the immune system, extensive immune phenotyping of our patients revealed alterations in the T cell compartment and lack of peripheral type 2 innate lymphoid cells (ILC2s), consistent with the findings described in Bcl11b-deficient mice. Unsupervised analysis of 102 T lymphocyte subpopulations showed that the patients clearly cluster apart from healthy children, further supporting the common aetiology of the disorder. Taken together, we show here that mutations leading either to BCL11B haploinsufficiency or to a truncated BCL11B protein clinically cause a non-syndromic neurodevelopmental delay. In addition, we suggest that missense mutations affecting specific sites within zinc-finger domains might result in distinct and more severe clinical outcomes.


Assuntos
Transtornos do Neurodesenvolvimento/genética , Proteínas Repressoras/genética , Proteínas Repressoras/fisiologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/fisiologia , Adolescente , Animais , Criança , Pré-Escolar , Feminino , Regulação da Expressão Gênica/genética , Mutação em Linhagem Germinativa , Haploinsuficiência , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Linfócitos/patologia , Linfócitos/fisiologia , Masculino , Camundongos , Mutação , Proteínas Repressoras/metabolismo , Linfócitos T/fisiologia , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/metabolismo
20.
Cell Rep ; 23(11): 3392-3406, 2018 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-29898407

RESUMO

We studied 137 primary testicular germ cell tumors (TGCTs) using high-dimensional assays of genomic, epigenomic, transcriptomic, and proteomic features. These tumors exhibited high aneuploidy and a paucity of somatic mutations. Somatic mutation of only three genes achieved significance-KIT, KRAS, and NRAS-exclusively in samples with seminoma components. Integrated analyses identified distinct molecular patterns that characterized the major recognized histologic subtypes of TGCT: seminoma, embryonal carcinoma, yolk sac tumor, and teratoma. Striking differences in global DNA methylation and microRNA expression between histology subtypes highlight a likely role of epigenomic processes in determining histologic fates in TGCTs. We also identified a subset of pure seminomas defined by KIT mutations, increased immune infiltration, globally demethylated DNA, and decreased KRAS copy number. We report potential biomarkers for risk stratification, such as miRNA specifically expressed in teratoma, and others with molecular diagnostic potential, such as CpH (CpA/CpC/CpT) methylation identifying embryonal carcinomas.


Assuntos
Neoplasias Embrionárias de Células Germinativas/patologia , Neoplasias Testiculares/patologia , Variações do Número de Cópias de DNA , Metilação de DNA , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , MicroRNAs/metabolismo , Neoplasias Embrionárias de Células Germinativas/classificação , Neoplasias Embrionárias de Células Germinativas/metabolismo , Proteínas Proto-Oncogênicas c-kit/genética , Proteínas Proto-Oncogênicas c-kit/metabolismo , Seminoma/metabolismo , Seminoma/patologia , Neoplasias Testiculares/classificação , Neoplasias Testiculares/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismo
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