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1.
Am J Hum Genet ; 108(1): 115-133, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33308444

RESUMO

Signal peptide-CUB-EGF domain-containing protein 3 (SCUBE3) is a member of a small family of multifunctional cell surface-anchored glycoproteins functioning as co-receptors for a variety of growth factors. Here we report that bi-allelic inactivating variants in SCUBE3 have pleiotropic consequences on development and cause a previously unrecognized syndromic disorder. Eighteen affected individuals from nine unrelated families showed a consistent phenotype characterized by reduced growth, skeletal features, distinctive craniofacial appearance, and dental anomalies. In vitro functional validation studies demonstrated a variable impact of disease-causing variants on transcript processing, protein secretion and function, and their dysregulating effect on bone morphogenetic protein (BMP) signaling. We show that SCUBE3 acts as a BMP2/BMP4 co-receptor, recruits the BMP receptor complexes into raft microdomains, and positively modulates signaling possibly by augmenting the specific interactions between BMPs and BMP type I receptors. Scube3-/- mice showed craniofacial and dental defects, reduced body size, and defective endochondral bone growth due to impaired BMP-mediated chondrogenesis and osteogenesis, recapitulating the human disorder. Our findings identify a human disease caused by defective function of a member of the SCUBE family, and link SCUBE3 to processes controlling growth, morphogenesis, and bone and teeth development through modulation of BMP signaling.


Assuntos
Osso e Ossos/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Deficiências do Desenvolvimento/metabolismo , Osteogênese/fisiologia , Transdução de Sinais/fisiologia , Animais , Proteína Morfogenética Óssea 2/metabolismo , Proteína Morfogenética Óssea 4/metabolismo , Proteínas Morfogenéticas Ósseas/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Células HEK293 , Células Hep G2 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células MCF-7 , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL
2.
Int J Cancer ; 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33320972

RESUMO

Pediatric low-grade gliomas (pLGGs) are the most frequent brain tumor in children. Adjuvant treatment, consisting in chemotherapy and radiotherapy, is often necessary if a complete surgical resection cannot be obtained. Traditional treatment approaches result in a significant long-term morbidity, with a detrimental impact on quality of life. Dysregulation of the mitogen-activated protein kinase (MAPK) pathway is the molecular hallmark of pLGGs and hyperactivation of the downstream mammalian target of rapamycin (mTOR) pathway is frequently observed. We report clinical and radiological results of front-line treatment with everolimus in 10 consecutive patients diagnosed with m-TOR positive pLGGs at the Bambino Gesù Children's Hospital in Rome, Italy. Median duration of treatment was 19 months (range from 13-60). Brain magnetic resonance imaging showed stable disease in 7 patients, partial response in 1 and disease progression in 2. Therapy-related adverse events were always reversible after dose reduction or temporary treatment interruption. To the best of our knowledge, this is the first report of everolimus treatment for chemo- and radiotherapy-naïve children with pLGG. Our results provide preliminary support, despite low sample size, for the use of everolimus as target therapy in pLGG showing lack of progression with a manageable toxicity profile.

3.
Front Genet ; 11: 565868, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33193651

RESUMO

Inositol polyphosphate-5-phosphatase K [INPP5K (MIM: 607875)] acts as a PIP3 5-phosphatase and regulates actin cytoskeleton, insulin, and cell migration. Biallelic pathogenic variants in INPP5K have recently been reported in patients affected by a form of muscular dystrophy with childhood onset. Affected patients have limb girdle muscle weakness, often associated with bilateral cataracts, short stature, and intellectual disability. Here we report four patients affected by INPP5K-related muscle dystrophy, who were apparently unrelated but originated from the same geographical area in South Italy. These patients manifest a recognizable phenotype characterized by early onset muscular dystrophy associated with short stature and intellectual disability. All affected subjects were homozygous or compound heterozygous for the c.67G > A (p.Val23Met) missense change and shared a common haplotype, indicating the occurrence of a founder effect.

4.
Am J Hum Genet ; 107(3): 499-513, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32721402

RESUMO

Signal transduction through the RAF-MEK-ERK pathway, the first described mitogen-associated protein kinase (MAPK) cascade, mediates multiple cellular processes and participates in early and late developmental programs. Aberrant signaling through this cascade contributes to oncogenesis and underlies the RASopathies, a family of cancer-prone disorders. Here, we report that de novo missense variants in MAPK1, encoding the mitogen-activated protein kinase 1 (i.e., extracellular signal-regulated protein kinase 2, ERK2), cause a neurodevelopmental disease within the RASopathy phenotypic spectrum, reminiscent of Noonan syndrome in some subjects. Pathogenic variants promote increased phosphorylation of the kinase, which enhances translocation to the nucleus and boosts MAPK signaling in vitro and in vivo. Two variant classes are identified, one of which directly disrupts binding to MKP3, a dual-specificity protein phosphatase negatively regulating ERK function. Importantly, signal dysregulation driven by pathogenic MAPK1 variants is stimulus reliant and retains dependence on MEK activity. Our data support a model in which the identified pathogenic variants operate with counteracting effects on MAPK1 function by differentially impacting the ability of the kinase to interact with regulators and substrates, which likely explains the minor role of these variants as driver events contributing to oncogenesis. After nearly 20 years from the discovery of the first gene implicated in Noonan syndrome, PTPN11, the last tier of the MAPK cascade joins the group of genes mutated in RASopathies.


Assuntos
Carcinogênese/genética , Proteína Quinase 1 Ativada por Mitógeno/genética , Transtornos do Neurodesenvolvimento/genética , Síndrome de Noonan/genética , Pré-Escolar , Feminino , Humanos , Sistema de Sinalização das MAP Quinases/genética , Masculino , Mutação de Sentido Incorreto/genética , Transtornos do Neurodesenvolvimento/patologia , Síndrome de Noonan/fisiopatologia , Fenótipo , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Transdução de Sinais , Sequenciamento Completo do Exoma , Proteínas ras/genética
6.
Am J Hum Genet ; 106(3): 356-370, 2020 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-32109418

RESUMO

Genetic syndromes frequently present with overlapping clinical features and inconclusive or ambiguous genetic findings which can confound accurate diagnosis and clinical management. An expanding number of genetic syndromes have been shown to have unique genomic DNA methylation patterns (called "episignatures"). Peripheral blood episignatures can be used for diagnostic testing as well as for the interpretation of ambiguous genetic test results. We present here an approach to episignature mapping in 42 genetic syndromes, which has allowed the identification of 34 robust disease-specific episignatures. We examine emerging patterns of overlap, as well as similarities and hierarchical relationships across these episignatures, to highlight their key features as they are related to genetic heterogeneity, dosage effect, unaffected carrier status, and incomplete penetrance. We demonstrate the necessity of multiclass modeling for accurate genetic variant classification and show how disease classification using a single episignature at a time can sometimes lead to classification errors in closely related episignatures. We demonstrate the utility of this tool in resolving ambiguous clinical cases and identification of previously undiagnosed cases through mass screening of a large cohort of subjects with developmental delays and congenital anomalies. This study more than doubles the number of published syndromes with DNA methylation episignatures and, most significantly, opens new avenues for accurate diagnosis and clinical assessment in individuals affected by these disorders.


Assuntos
Metilação de DNA , Transtornos do Neurodesenvolvimento/genética , Fenótipo , Estudos de Coortes , Heterogeneidade Genética , Humanos , Síndrome
7.
Clin Epigenetics ; 12(1): 7, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31910894

RESUMO

BACKGROUND: We previously associated HIST1H1E mutations causing Rahman syndrome with a specific genome-wide methylation pattern. RESULTS: Methylome analysis from peripheral blood samples of six affected subjects led us to identify a specific hypomethylated profile. This "episignature" was enriched for genes involved in neuronal system development and function. A computational classifier yielded full sensitivity and specificity in detecting subjects with Rahman syndrome. Applying this model to a cohort of undiagnosed probands allowed us to reach diagnosis in one subject. CONCLUSIONS: We demonstrate an epigenetic signature in subjects with Rahman syndrome that can be used to reach molecular diagnosis.

8.
Pediatr Neurol ; 104: 40-45, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31836334

RESUMO

BACKGROUND: Congenital ataxias associated with cerebellar atrophy are clinically heterogeneous conditions with a variable age of onset and a diverse molecular basis. The hypothesis-free approach of genomic sequencing has led to the discovery of new genes implicated in these disorders and the identification of unexpected genotype-phenotype correlations. Although a recurrent heterozygous mutation (p.Arg1715His) in CACNA1G is known to cause adult-onset spinocerebellar ataxia 42 (SCA42*616795), gain-of-function mutations in this gene have recently been identified by whole exome sequencing (WES) in four children with cerebellar atrophy and ataxia, psychomotor delay, and other variable features. METHODS: We describe four children from unrelated families with cerebellar anomalies on magnetic resonance imaging (atrophy or hypoplasia of the cerebellar vermis), hypertonia, psychomotor and speech delay, severe intellectual disability, ophthalmologic features and peculiar dysmorphic traits. All patients underwent a trio-based WES analysis. Clinical records were used to characterize the clinical profile of this newly recognized disorder. RESULTS: Two previously reported de novo disease-causing mutations in CACNA1G (c.2881G>A, p.Ala961Thr and c.4591A>G, p.Met1531Val) were identified in these patients, providing further evidence of the specific impact of these variants. All four patients exhibit distinctive dysmorphic and ectodermal features which overlap those of the previously reported patients, allowing us to define the major features characterizing this homogeneous neurodevelopmental syndromic disorder associated with upregulated CACNA1G function. CONCLUSION: Our findings confirm the specific association between a narrow spectrum of missense mutations in CACNA1G and a novel syndrome with infantile-onset cerebellar ataxiaand provide a dysmorphologic delineation of this novel neurodevelopmental trait.

9.
Am J Hum Genet ; 105(3): 493-508, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31447100

RESUMO

Histones mediate dynamic packaging of nuclear DNA in chromatin, a process that is precisely controlled to guarantee efficient compaction of the genome and proper chromosomal segregation during cell division and to accomplish DNA replication, transcription, and repair. Due to the important structural and regulatory roles played by histones, it is not surprising that histone functional dysregulation or aberrant levels of histones can have severe consequences for multiple cellular processes and ultimately might affect development or contribute to cell transformation. Recently, germline frameshift mutations involving the C-terminal tail of HIST1H1E, which is a widely expressed member of the linker histone family and facilitates higher-order chromatin folding, have been causally linked to an as-yet poorly defined syndrome that includes intellectual disability. We report that these mutations result in stable proteins that reside in the nucleus, bind to chromatin, disrupt proper compaction of DNA, and are associated with a specific methylation pattern. Cells expressing these mutant proteins have a dramatically reduced proliferation rate and competence, hardly enter into the S phase, and undergo accelerated senescence. Remarkably, clinical assessment of a relatively large cohort of subjects sharing these mutations revealed a premature aging phenotype as a previously unrecognized feature of the disorder. Our findings identify a direct link between aberrant chromatin remodeling, cellular senescence, and accelerated aging.


Assuntos
Senescência Celular/fisiologia , Histonas/fisiologia , Aneuploidia , Nucléolo Celular/metabolismo , Criança , Cromatina/metabolismo , Metilação de DNA , Feminino , Histonas/química , Humanos , Lactente , Masculino , Pessoa de Meia-Idade
10.
Clin Genet ; 96(6): 585-589, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31448411

RESUMO

Signal Transducer and Activator of Transcription 1 (STAT1) is a DNA-binding signal transducer that regulates transcription of specific genes in response to IFNγ and IFNα/ß stimulation. Loss-of-function mutations impairing STAT1 activity are known to confer susceptibility to intracellular bacterial and viral diseases. Conversely, the few known activating mutations of STAT1 allow predisposition to chronic mucocutaneous candidiasis disease, and occur in patients with combined immunodeficiency and defective Th1 and Th17 responses. Here, we report on a de novo gain-of-function (GoF) STAT1 mutation (c.1398C>G, p.Ser466Arg) identified by exome sequencing in an individual with brain calcification, arthritis, recurrent pericarditis, leukopenia, thrombocytopenia and low C3 levels, a phenotype resembling an interferonopathy. The Ser466Arg change affects a highly conserved residue located in the DNA binding domain of the protein and the amino acid substitution was documented to have an activating role both in vitro and in vivo. Altogether, clinical features and functional studies are compatible with hyperactivation of the Interferon pathways, highlighting a role of STAT1 GoF mutation in clinical phenotypes fitting interferonopathies.


Assuntos
Interferons/metabolismo , Mutação/genética , Fator de Transcrição STAT1/genética , Adolescente , Pré-Escolar , Células HEK293 , Humanos , Masculino , Fenótipo
11.
BMC Pediatr ; 19(1): 203, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31215483

RESUMO

BACKGROUND: Pediatric ARDS still represents a difficult challenge in Pediatric Intensive Care Units (PICU). Among different treatments proposed, exogenous surfactant showed conflicting results. Aim of this multicenter retrospective observational study was to evaluate whether poractant alfa use in pediatric ARDS might improve gas exchange in children less than 2 years old, according to a shared protocol. METHODS: The study was carried out in fourteen Italian PICUs after dissemination of a standardized protocol for surfactant administration within the Italian PICU network. The protocol provides the administration of surfactant (50 mg/kg) divided in two doses: the first dose is used as a bronchoalveolar lavage while the second as supplementation. Blood gas exchange variations before and after surfactant use were recorded. RESULTS: Sixty-nine children, age 0-24 months, affected by Acute Respiratory Distress Syndrome treated with exogenous porcine surfactant were enrolled. Data collection consisted of patient demographics, respiratory variables and arterial blood gas analysis. The most frequent reasons for PICU admission were acute respiratory failure, mainly bronchiolitis and pneumonia, and septic shock. Fifty-four children (78.3%) had severe ARDS (define by oxygen arterial pressure and inspired oxygen fraction ratio (P/F) < 100), 15 (21.7%) had moderate ARDS (100 < P/F < 200). PO2, P/F, Oxygenation Index (OI) and pH showed a significant improvement after surfactant use with respect to baseline (p < 0.001 at each included time-point for each parameter). No significant difference in blood gas variations were observed among four different subgroups of diseases (bronchiolitis, pneumonia, septic shock and others). Overall, 11 children died (15.9%) and among these, 10 (90.9%) had complex chronic conditions. Two children (18.2%) died while being treated with Extracorporeal Membrane Oxygenation (ECMO). Mortality for severe pARDS was 20.4%. CONCLUSION: The use of porcine Surfactant improves oxygenation, P/F ratio, OI and pH in a population of children with moderate or severe pARDS caused by multiple diseases. A shared protocol seems to be a good option to obtain the same criteria of enrollment among different PICUs and define a unique way of use and administration of the drug for future studies.


Assuntos
Produtos Biológicos/administração & dosagem , Fosfolipídeos/administração & dosagem , Troca Gasosa Pulmonar/efeitos dos fármacos , Surfactantes Pulmonares/administração & dosagem , Insuficiência Respiratória/tratamento farmacológico , Doença Aguda , Fatores Etários , Bronquiolite/tratamento farmacológico , Protocolos Clínicos , Intervalos de Confiança , Oxigenação por Membrana Extracorpórea/mortalidade , Estudos de Viabilidade , Feminino , Humanos , Lactente , Recém-Nascido , Unidades de Terapia Intensiva Pediátrica , Itália , Masculino , Razão de Chances , Pneumonia/tratamento farmacológico , Síndrome do Desconforto Respiratório do Recém-Nascido/sangue , Síndrome do Desconforto Respiratório do Recém-Nascido/tratamento farmacológico , Insuficiência Respiratória/sangue , Insuficiência Respiratória/mortalidade , Estudos Retrospectivos , Sucção , Síndrome
12.
Cell Death Dis ; 10(3): 201, 2019 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-30814510

RESUMO

The pressure towards innovation and creation of new model systems in regenerative medicine and cancer research has fostered the development of novel potential therapeutic applications. Kidney injuries provoke a high request of organ transplants making it the most demanding system in the field of regenerative medicine. Furthermore, renal cancer frequently threaten patients' life and aggressive forms still remain difficult to treat. Ethical issues related to the use of embryonic stem cells, has fueled research on adult, patient-specific pluripotent stem cells as a model for discovery and therapeutic development, but to date, normal and cancerous renal experimental models are lacking. Several research groups are focusing on the development of organoid cultures. Since organoids mimic the original tissue architecture in vitro, they represent an excellent model for tissue engineering studies and cancer therapy testing. We established normal and tumor renal cell carcinoma organoids previously maintained in a heterogeneous multi-clone stem cell-like enriching medium. Starting from adult normal kidney specimens, we were able to isolate and propagate organoid 3D-structures composed of both differentiated and undifferentiated cells while expressing nephron specific markers. Furthermore, we were capable to establish organoids derived from cancer tissues although with a success rate inferior to that of their normal counterpart. Cancer cultures displayed epithelial and mesenchymal phenotype while retaining tumor specific markers. Of note, tumor organoids recapitulated neoplastic masses when orthotopically injected into immunocompromised mice. Our data suggest an innovative approach of long-term establishment of normal- and cancer-derived renal organoids obtained from cultures of fleshly dissociated adult tissues. Our results pave the way to organ replacement pioneering strategies as well as to new models for studying drug-induced nephrotoxicity and renal diseases. Along similar lines, deriving organoids from renal cancer patients opens unprecedented opportunities for generation of preclinical models aimed at improving therapeutic treatments.


Assuntos
Rim/patologia , Organoides/metabolismo , Medicina de Precisão/métodos , Medicina Regenerativa/métodos , Insuficiência Renal Crônica/terapia , Humanos , Insuficiência Renal Crônica/patologia
13.
Hum Mutat ; 40(6): 721-728, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30825388

RESUMO

The pathogenic variants in the neuroblastoma-amplified sequence (NBAS) are associated with a clinical spectrum involving the hepatic, skeletal, ocular, and immune systems. Here, we report on two unrelated subjects with a complex phenotype solved by whole-exome sequencing, who shared a synonymous change in NBAS that was documented to affect the transcript processing and co-occurring with a truncating change. Starting from these two cases, we systematically assessed the clinical information available for all subjects with biallelic NBAS pathogenic variants (73 cases in total). We revealed a recognizable facial profile (hypotelorism, thin lips, pointed chin, and "progeroid" appearance) determined by using DeepGestalt facial recognition technology, and we provide evidence for the occurrence of genotype-phenotype correlations. Notably, severe hepatic involvement was associated with variants affecting the NBAS-Nter and Sec39 domains, whereas milder liver involvement and immunodeficiency were generally associated with variants located at the N-terminus and C-terminus of the protein. Remarkably, no patient was reported to carry two nonsense variants, suggesting lethality of complete NBAS loss-of-function.


Assuntos
Anormalidades Múltiplas/genética , Proteínas de Neoplasias/genética , Mutação Silenciosa , Sequenciamento Completo do Exoma/métodos , Criança , Pré-Escolar , Feminino , Estudos de Associação Genética , Humanos , Mutação com Perda de Função , Masculino , Proteínas de Neoplasias/química , Linhagem , Domínios Proteicos
14.
Eur J Med Genet ; 62(6): 103534, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30189253

RESUMO

TARP syndrome (TARPS) is an X-linked syndromic condition including Robin sequence, congenital heart defects, developmental delay, feeding difficulties and talipes equinovarus, as major features. The disease is caused by inactivating mutations in RBM10 which encodes for a RNA binding motif protein involved in transcript processing. We herein report a male born from healthy and non-consanguineous parents, presenting prenatal record of intrauterine fetal growth retardation, and postnatal features including growth and developmental delays, CNS abnormalities, facial dysmorphisms, bilateral syndactyly at the hands, talipes equinovarus and congenital heart defects. By using trio-based Whole Exome Sequencing approach, a maternally inherited RBM10 frameshift variant causing decay of the RBM10 transcript was identified. Despite the syndrome is considered lethal in affected males, our subject with molecularly confirmed TARPS is still alive at 11 years of age supporting the chance of surviving. Long-term surviving in TARPS is extremely rare and should be considered in genetic counselling and clinical follow up of the syndrome. We provide the natural history of the syndrome, reviewing the major clinical characteristics. Congenital heart defects are confirmed as specific diagnostic markers for the syndrome. In addition, cardiac anatomical details are defining a possible clinical overlap with syndromic conditions related to the hedgehog pathway and/or primary cilium anomalies as Oral-Facial-Digital or Smith-Lemli-Opitz syndromes.


Assuntos
Pé Torto Equinovaro/genética , Cardiopatias Congênitas/genética , Síndrome de Pierre Robin/genética , Proteínas de Ligação a RNA/genética , Criança , Pé Torto Equinovaro/patologia , Diagnóstico Diferencial , Cardiopatias Congênitas/patologia , Humanos , Masculino , Síndrome de Pierre Robin/patologia
15.
Parkinsonism Relat Disord ; 61: 207-210, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30337205

RESUMO

INTRODUCTION: Clathrins play a key role in endocytosis, recycling, and trafficking as well as the generation of presynaptic vesicles. We report a new clinical condition associated with a de novo variant in the CLTC gene, which encodes the clathrin heavy polypeptide. CASE REPORT: This 30-year-old woman presented with a developmental disorder during childhood that progressed to mild cognitive decline in late childhood and relapsing-remitting hypokinetic-rigid syndrome with severe achalasia, weight loss, and mood disorder in adulthood. 123I-Ioflupane SPECT was normal. Blood phenylalanine was slightly increased and PAH sequencing revealed compound heterozygosity for two variants, p.[Asp151Glu]:[Thr380Met]. CSF examination unexpectedly detected a remarkable reduction of homovanillic, 5-hydroxyindolacetic, and 5-methylthetrahydrofolic acids, which could not be ascribed to any alteration of tetrahydrobiopterin and related biogenic amine pathways. METHODS: Trio-based exome sequencing was performed. RESULT: A de novo missense variant (c.2669C > T/p.Pro890Leu) was detected in CLTC. Treatment with biogenic amine precursors was ineffective, while the inhibitor of MAO-A selegiline resulted in persistent clinical improvement. CONCLUSIONS: We suggest CLTC defect as a new disorder of biogenic amine trafficking, resulting in neurodevelopmental derangement and movement disorder. Neurotransmitter depletion in CSF may be a biomarker of this disease, and selegiline a possible treatment option.


Assuntos
Monoaminas Biogênicas/metabolismo , Cadeias Pesadas de Clatrina/genética , Deficiência Intelectual/diagnóstico , Transtornos Parkinsonianos/diagnóstico , Transdução de Sinais/genética , Adulto , Idade de Início , Feminino , Humanos , Deficiência Intelectual/genética , Transtornos Parkinsonianos/genética
16.
Am J Hum Genet ; 103(4): 621-630, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30290154

RESUMO

Aberrant activation or inhibition of potassium (K+) currents across the plasma membrane of cells has been causally linked to altered neurotransmission, cardiac arrhythmias, endocrine dysfunction, and (more rarely) perturbed developmental processes. The K+ channel subfamily K member 4 (KCNK4), also known as TRAAK (TWIK-related arachidonic acid-stimulated K+ channel), belongs to the mechano-gated ion channels of the TRAAK/TREK subfamily of two-pore-domain (K2P) K+ channels. While K2P channels are well known to contribute to the resting membrane potential and cellular excitability, their involvement in pathophysiological processes remains largely uncharacterized. We report that de novo missense mutations in KCNK4 cause a recognizable syndrome with a distinctive facial gestalt, for which we propose the acronym FHEIG (facial dysmorphism, hypertrichosis, epilepsy, intellectual disability/developmental delay, and gingival overgrowth). Patch-clamp analyses documented a significant gain of function of the identified KCNK4 channel mutants basally and impaired sensitivity to mechanical stimulation and arachidonic acid. Co-expression experiments indicated a dominant behavior of the disease-causing mutations. Molecular dynamics simulations consistently indicated that mutations favor sealing of the lateral intramembrane fenestration that has been proposed to negatively control K+ flow by allowing lipid access to the central cavity of the channel. Overall, our findings illustrate the pleiotropic effect of dysregulated KCNK4 function and provide support to the hypothesis of a gating mechanism based on the lateral fenestrations of K2P channels.


Assuntos
Ativação do Canal Iônico/genética , Mutação/genética , Transtornos do Neurodesenvolvimento/genética , Canais de Potássio/genética , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Simulação de Dinâmica Molecular
17.
Arch Oral Biol ; 91: 96-102, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29705498

RESUMO

OBJECTIVE: The aim of this study was the clinical and molecular characterization of a family segregating a trait consisting of a phenotype specifically involving the maxillary canines, including agenesis, impaction and ectopic eruption, characterized by incomplete penetrance and variable expressivity. DESIGN: Clinical standardized assessment of 14 family members and a whole-exome sequencing (WES) of three affected subjects were performed. WES data analyses (sequence alignment, variant calling, annotation and prioritization) were carried out using an in-house implemented pipeline. Variant filtering retained coding and splice-site high quality private and rare variants. Variant prioritization was performed taking into account both the disruptive impact and the biological relevance of individual variants and genes. Sanger sequencing was performed to validate the variants of interest and to carry out segregation analysis. RESULTS: Prioritization of variants "by function" allowed the identification of multiple variants contributing to the trait, including two concomitant heterozygous variants in EDARADD (c.308C>T, p.Ser103Phe) and COL5A1 (c.1588G>A, p.Gly530Ser), specifically associated with a more severe phenotype (i.e. canine agenesis). Differently, heterozygous variants in genes encoding proteins with a role in the WNT pathway were shared by subjects showing a phenotype of impacted/ectopic erupted canines. CONCLUSIONS: This study characterized the genetic contribution underlying a complex trait consisting of isolated canine anomalies in a medium-sized family, highlighting the role of WNT and EDA cell signaling pathways in tooth development.


Assuntos
Anodontia/genética , Dente Canino/anormalidades , Erupção Dentária , Sequenciamento Completo do Exoma/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Ligação ao Cálcio , Colágeno Tipo V/genética , Dente Canino/diagnóstico por imagem , Análise Mutacional de DNA , Ectodisplasinas/metabolismo , Proteína de Domínio de Morte Associada a Edar/genética , Feminino , Proteínas Fetais/genética , Frequência do Gene , Heterozigoto , Humanos , Itália , Masculino , Maxila , Pessoa de Meia-Idade , Mutação , Proteínas do Tecido Nervoso/genética , Linhagem , Fenótipo , Radiografia Panorâmica , Alinhamento de Sequência , Proteínas com Domínio T/genética , Trombospondinas/genética , Via de Sinalização Wnt , Adulto Jovem
18.
Neurogenetics ; 19(2): 111-121, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29691679

RESUMO

Hereditary spastic paraplegias (HSP) are clinical and genetic heterogeneous diseases with more than 80 disease genes identified thus far. Studies on large cohorts of HSP patients showed that, by means of current technologies, the percentage of genetically solved cases is close to 50%. Notably, the percentage of molecularly confirmed diagnoses decreases significantly in sporadic patients. To describe our diagnostic molecular genetic approach on patients with pediatric-onset pure and complex HSP, 47 subjects with HSP underwent molecular screening of 113 known and candidate disease genes by targeted capture and massively parallel sequencing. Negative cases were successively analyzed by multiplex ligation-dependent probe amplification (MLPA) analysis for the SPAST gene and high-resolution SNP array analysis for genome-wide CNV detection. Diagnosis was molecularly confirmed in 29 out of 47 (62%) patients, most of whom had clinical diagnosis of cHSP. Although SPG11 and SPG4 remain the most frequent cause of, respectively, complex and pure HSP, a large number of pathogenic variants were disclosed in POLR3A, FA2H, DDHD2, ATP2B4, ENTPD1, ERLIN2, CAPN1, ALS2, ADAR1, RNASEH2B, TUBB4A, ATL1, and KIF1A. In a subset of these disease genes, phenotypic expansion and novel genotype-phenotype correlations were recognized. Notably, SNP array analysis did not provide any significant contribution in increasing the diagnostic yield. Our findings document the high diagnostic yield of targeted sequencing for patients with pediatric-onset, complex, and pure HSP. MLPA for SPAST and SNP array should be limited to properly selected cases based on clinical suspicion.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Paraplegia Espástica Hereditária/diagnóstico , Paraplegia Espástica Hereditária/genética , Adolescente , Idade de Início , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Estudos de Associação Genética , Testes Genéticos/métodos , Humanos , Lactente , Recém-Nascido , Masculino , Mutação , Polimorfismo de Nucleotídeo Único
19.
Clin Genet ; 93(2): 401-407, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28374925

RESUMO

Kabuki syndrome is a genetically heterogeneous disorder characterized by postnatal growth retardation, skeletal abnormalities, intellectual disability, facial dysmorphisms and a variable range of organ malformations. In ~30% of affected individuals, the underlying genetic defect remains unknown. A small number of inactivating heterozygous HNRNPK mutations has recently been reported to be associated with a condition partially overlapping or suggestive of Kabuki syndrome. Here, we report on an 11-year-old girl with a complex phenotype in whom the diagnosis of KS was suggested but molecular testing for the known causative disease genes was negative. Whole-exome sequencing identified a previously undescribed de novo truncating mutation in HNRNPK as the molecular defect underlying the trait. Analysis of available records of patients with HNRNPK haploinsufficiency was performed to delineate the associated clinical phenotype and outline their distinguishing features in comparison with the KS clinical spectrum. The clinical profile associated with inactivating HNRNPK mutations supports the idea that the associated disorder should be considered as a distinct nosologic entity clinically related to KS, and that the condition should be considered in differential diagnosis with KS, in particular in subjects exhibiting brain malformation (nodular heterotopia), craniosynostosis, and polydactyly.


Assuntos
Anormalidades Múltiplas/genética , Face/anormalidades , Doenças Hematológicas/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/genética , Deficiência Intelectual/genética , Doenças Vestibulares/genética , Sequenciamento Completo do Exoma , Anormalidades Múltiplas/fisiopatologia , Criança , Exoma/genética , Face/fisiopatologia , Feminino , Haploinsuficiência/genética , Doenças Hematológicas/fisiopatologia , Humanos , Deficiência Intelectual/fisiopatologia , Mutação , Fenótipo , Doenças Vestibulares/fisiopatologia
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