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Background: Patients, families, the healthcare system, and society as a whole are all significantly impacted by rare diseases (RDs). According to various classifications, there are currently up to 9,000 different rare diseases that have been recognized, and new diseases are discovered every month. Although very few people are affected by each uncommon disease individually, millions of people are thought to be impacted globally when all these conditions are considered. Therefore, RDs represent an important public health concern. Although crucial for clinical care, early and correct diagnosis is still difficult to achieve in many nations, especially those with low and middle incomes. Consequently, a sizeable amount of the overall burden of RD is attributable to undiagnosed RD (URD). Existing barriers and policy aspects impacting the care of patients with RD and URD remain to be investigated. Methods: To identify unmet needs and opportunities for patients with URD, the Developing Nations Working Group of the Undiagnosed Diseases Network International (DNWG-UDNI) conducted a survey among its members, who were from 20 different nations. The survey used a mix of multiple choice and dedicated open questions covering a variety of topics. To explore reported needs and analyze them in relation to national healthcare economical aspects, publicly available data on (a) World Bank ranking; (b) Current health expenditure per capita; (c) GDP per capita; (d) Domestic general government health expenditure (% of GDP); and (e) Life expectancy at birth, total (years) were incorporated in our study. Results: This study provides an in-depth evaluation of the unmet needs for 20 countries: low-income (3), middle-income (10), and high-income (7). When analyzing reported unmet needs, almost all countries (N = 19) indicated that major barriers still exist when attempting to improve the care of patients with UR and/or URD; most countries report unmet needs related to the availability of specialized care and dedicated facilities. However, while the countries ranked as low income by the World Bank showed the highest prevalence of referred unmet needs across the different domains, no specific trend appeared when comparing the high, upper, and low-middle income nations. No overt trend was observed when separating countries by current health expenditure per capita, GDP per capita, domestic general government health expenditure (% of GDP) and life expectancy at birth, total (years). Conversely, both the GDP and domestic general government health expenditure for each country impacted the presence of ongoing research. Conclusion: We found that policy characteristics varied greatly with the type of health system and country. No overall pattern in terms of referral for unmet needs when separating countries by main economic or health indicators were observed. Our findings highlight the importance of identifying actionable points (e.g., implemented orphan drug acts or registries where not available) in order to improve the care and diagnosis of RDs and URDs on a global scale.
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Enfermedades no Diagnosticadas , Recién Nacido , Humanos , Enfermedades Raras/diagnóstico , Enfermedades Raras/epidemiología , Salud Global , Atención a la Salud , Gastos en SaludRESUMEN
Collectively, rare genetic disorders affect a substantial portion of the world's population. In most cases, those affected face difficulties in receiving a clinical diagnosis and genetic characterization. The understanding of the molecular mechanisms of these diseases and the development of therapeutic treatments for patients are also challenging. However, the application of recent advancements in genome sequencing/analysis technologies and computer-aided tools for predicting phenotype-genotype associations can bring significant benefits to this field. In this review, we highlight the most relevant online resources and computational tools for genome interpretation that can enhance the diagnosis, clinical management, and development of treatments for rare disorders. Our focus is on resources for interpreting single nucleotide variants. Additionally, we present use cases for interpreting genetic variants in clinical settings and review the limitations of these results and prediction tools. Finally, we have compiled a curated set of core resources and tools for analyzing rare disease genomes. Such resources and tools can be utilized to develop standardized protocols that will enhance the accuracy and effectiveness of rare disease diagnosis.
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Introduction: Rare diseases (RD) are a health priority worldwide, overall affecting hundreds of millions of people globally. Early and accurate diagnosis is essential to support clinical care but remains challenging in many countries, especially the low- and medium-income ones. Hence, undiagnosed RD (URD) account for a significant portion of the overall RD burden. Methods: In October 2020, the Developing Nations Working Group of the Undiagnosed Diseases Network International (DNWG-UDNI) launched a survey among its members, belonging to 20 countries across all continents, to map unmet needs and opportunities for patients with URD. The survey was based on questions with open answers and included eight different domains. Conflicting interpretations were resolved in contact with the partners involved. Results: All members responded to the survey. The results indicated that the scientific and medical centers make substantial efforts to respond to the unmet needs of patients. In most countries, there is a high awareness of RD issues. Scarcity of resources was highlighted as a major problem, leading to reduced availability of diagnostic expertise and research. Serious equity in accessibility to services were highlighted both within and between participating countries. Regulatory problems, including securing informed consent, difficulties in sending DNA to foreign laboratories, protection of intellectual property, and conflicts of interest on the part of service providers, remain issues of concern. Finally, most respondents stressed the need to strengthen international cooperation in terms of data sharing, clinical research, and diagnostic expertise for URD patients in low and medium income countries. Discussion: The survey highlighted that many countries experienced a discrepancy between the growing expertise and scientific value, the level of awareness and commitment on the part of relevant parties, and funding bodies. Country-tailored public health actions, including general syllabus of medical schools and of the education of other health professionals, are needed to reduce such gaps.
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Enfermedades no Diagnosticadas , Humanos , Enfermedades Raras/diagnóstico , Encuestas y CuestionariosRESUMEN
Background: Patient registries play a crucial role in supporting clinical practice, healthcare planning and medical research, offering a real-world picture on rare and complex connective tissue diseases (rCTDs). ERN ReCONNET launched the first European Registry Infrastructure with the aim to plan, upgrade and link registries for rCTDs, with the final goal to promote a harmonized data collection approach all over Europe for rCTDs. Methods: An online survey addressed to healthcare professionals and patients' representatives active in the field of rCTDs was integrated by an extensive database search in order to build a mapping of existing registries for rCTDs. Findings: A total of 140 registries were found, 38 of which include multiple diseases. No disease-specific registry was identified for relapsing polychondritis, mixed connective tissue disease and undifferentiated connective tissue disease. Discussion: This overview on the existing registries for rCTDs provides a useful starting point to identify the gaps and the strengths of registries on the coverage of rCTDs, and to develop a common data set and data collection approach for the establishment of the TogethERN ReCONNET Infrastructure.
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The unexpected outbreak of the COVID-19 disease had significant and enormous repercussions on the healthcare systems, such as the need to reorganise healthcare organisations in order to concentrate resources needed to the care of COVID-19 patients and to respond in general to this health emergency. Due to these challenges, the care of several chronic conditions was in many cases discontinued and patients and healthcare professionals treating these conditions had to cope with this new scenario. This was the case of the world rare diseases (RDs) that had to face this global emergency despite the vulnerability of people with RDs and the well-known need for high expertise required to treat and manage them. The numerous lessons learned so far regarding health emergencies and RDs should represent the basis for the establishment of new healthcare policies and plans aimed at ensuring the preparedness of our health systems in providing appropriate care to people living with RDs in the case of eventual new emergencies. This paper aims at providing pragmatic considerations that might be useful in designing future actions to create or optimise existing organisational models for the care of RDs in case of future emergencies or any other situation that might threaten the provision of routine care. These policies and plans should benefit from the multi-stakeholder RDs networks (such as the European Reference Networks), that should join forces at European, national, and local levels to minimise the economic, organisational, and health-related impact and the negative effects of potential emergencies on the RDs community. In order to design and develop these policies and plans, a decalogue of points to consider were developed to ensure appropriate care for people living with RDs in the case of eventual future health emergencies.
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COVID-19 , Atención a la Salud/organización & administración , Urgencias Médicas , Enfermedades Raras/terapia , Salud Global , Humanos , Pandemias , Enfermedades Raras/epidemiologíaRESUMEN
Rare and complex connective tissue diseases (rCTDs) encompass a considerable number of diseases and syndromes and their variability highly impacts on the clinical management, resulting in variable economic and organisational burden that might represent a challenge for healthcare systems. This paper is aimed at providing an overview of the most recent evidence regarding the economic and organisational impact of rCTDs. In particular, this work discusses the most relevant data on specific aspects related to health economics in rCTDs published in 2019.
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Enfermedades del Tejido Conjuntivo , Atención a la Salud , Enfermedades del Tejido Conjuntivo/diagnóstico , Enfermedades del Tejido Conjuntivo/epidemiología , Enfermedades del Tejido Conjuntivo/terapia , HumanosRESUMEN
Rare diseases (RD) patient registries are powerful instruments that help develop clinical research, facilitate the planning of appropriate clinical trials, improve patient care, and support healthcare management. They constitute a key information system that supports the activities of European Reference Networks (ERNs) on rare diseases. A rapid proliferation of RD registries has occurred during the last years and there is a need to develop guidance for the minimum requirements, recommendations and standards necessary to maintain a high-quality registry. In response to these heterogeneities, in the framework of RD-Connect, a European platform connecting databases, registries, biobanks and clinical bioinformatics for rare disease research, we report on a list of recommendations, developed by a group of experts, including members of patient organizations, to be used as a framework for improving the quality of RD registries. This list includes aspects of governance, Findable, Accessible, Interoperable and Reusable (FAIR) data and information, infrastructure, documentation, training, and quality audit. The list is intended to be used by established as well as new RD registries. Further work includes the development of a toolkit to enable continuous assessment and improvement of their organizational and data quality.
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Mejoramiento de la Calidad , Enfermedades Raras , Sistema de Registros/normas , Investigación Biomédica , Biología Computacional , Exactitud de los Datos , Europa (Continente) , Humanos , Almacenamiento y Recuperación de la Información/normasRESUMEN
In rare disease (RD) research, there is a huge need to systematically collect biomaterials, phenotypic, and genomic data in a standardized way and to make them findable, accessible, interoperable and reusable (FAIR). RD-Connect is a 6 years global infrastructure project initiated in November 2012 that links genomic data with patient registries, biobanks, and clinical bioinformatics tools to create a central research resource for RDs. Here, we present RD-Connect Registry & Biobank Finder, a tool that helps RD researchers to find RD biobanks and registries and provide information on the availability and accessibility of content in each database. The finder concentrates information that is currently sparse on different repositories (inventories, websites, scientific journals, technical reports, etc.), including aggregated data and metadata from participating databases. Aggregated data provided by the finder, if appropriately checked, can be used by researchers who are trying to estimate the prevalence of a RD, to organize a clinical trial on a RD, or to estimate the volume of patients seen by different clinical centers. The finder is also a portal to other RD-Connect tools, providing a link to the RD-Connect Sample Catalogue, a large inventory of RD biological samples available in participating biobanks for RD research. There are several kinds of users and potential uses for the RD-Connect Registry & Biobank Finder, including researchers collaborating with academia and the industry, dealing with the questions of basic, translational, and/or clinical research. As of November 2017, the finder is populated with aggregated data for 222 registries and 21 biobanks.
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Biología Computacional , Genómica , Metadatos , Enfermedades Raras/genética , Bancos de Muestras Biológicas , Investigación Biomédica , Bases de Datos Factuales , Humanos , Difusión de la Información , Pacientes , Enfermedades Raras/sangre , Enfermedades Raras/epidemiología , Sistema de RegistrosRESUMEN
Patient registries are an essential tool to increase current knowledge regarding rare diseases. Understanding these data is a vital step to improve patient treatments and to create the most adequate tools for personalized medicine. However, the growing number of disease-specific patient registries brings also new technical challenges. Usually, these systems are developed as closed data silos, with independent formats and models, lacking comprehensive mechanisms to enable data sharing. To tackle these challenges, we developed a Semantic Web based solution that allows connecting distributed and heterogeneous registries, enabling the federation of knowledge between multiple independent environments. This semantic layer creates a holistic view over a set of anonymised registries, supporting semantic data representation, integrated access, and querying. The implemented system gave us the opportunity to answer challenging questions across disperse rare disease patient registries. The interconnection between those registries using Semantic Web technologies benefits our final solution in a way that we can query single or multiple instances according to our needs. The outcome is a unique semantic layer, connecting miscellaneous registries and delivering a lightweight holistic perspective over the wealth of knowledge stemming from linked rare disease patient registries.
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Sistemas de Administración de Bases de Datos/estadística & datos numéricos , Almacenamiento y Recuperación de la Información/estadística & datos numéricos , Enfermedades Raras/epidemiología , Sistema de Registros/estadística & datos numéricos , Web Semántica/estadística & datos numéricos , Biología Computacional/métodos , Bases de Datos Factuales/estadística & datos numéricos , Humanos , Difusión de la Información/métodos , Internet/estadística & datos numéricos , Programas Informáticos/estadística & datos numéricosRESUMEN
OBJECTIVES: Sweat chloride test is the gold standard test for cystic fibrosis (CF) diagnosis. In 2014 the Istituto Superiore di Sanità established the Italian pilot external quality assessment program for CF sweat test (IEQA-ST). DESIGN AND METHODS: Ten laboratories, included among the 33 Italian CF Referral Centers, were selected and enrolled on the basis of their attitude to perform sweat test (ST) analysis by using methods recommended by the Italian Guidelines. They received three different sweat-like samples (normal, borderline and pathologic chloride concentration), with mock clinical indications, for analysis according to routine procedures. Assessment, performed by a panel of experts, covered analytical performance, interpretation and reporting of results; categories of "poor" and "satisfactory" performance were not defined. All data were managed through a web utility. RESULTS: The program identified important areas of interest and, in some case, of concern. It is important to underline that results are referred to a small proportion, i.e. about 30%, of Italian laboratories performing CF ST in the context of the Referral Centers. CONCLUSIONS: Data collected highlight the importance of participation in EQA programs as it may improve laboratory/clinical performance; our study represents a model for the setting up of a large-scale EQA scheme for ST.
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Cloruros/análisis , Técnicas de Laboratorio Clínico/normas , Fibrosis Quística/diagnóstico , Pruebas Diagnósticas de Rutina/normas , Laboratorios/normas , Control de Calidad , Sudor/química , Estudios de Seguimiento , Humanos , Italia , Proyectos Piloto , Estudios Prospectivos , Proyectos de InvestigaciónRESUMEN
OBJECTIVE: This work investigated the molecular cause responsible for a late-onset parkinsonism-dystonia phenotype in three Italian siblings, and clinically characterize this condition. METHODS: Extensive neurophysiological and neuroradiological exams were performed on the three sibs. Most frequent late-onset metabolic diseases were ruled out through laboratory and biochemical analyses. A whole exome sequencing (WES) approach was used to identify the molecular cause underlying this condition. RESULTS AND CONCLUSIONS: Peculiar neurologic phenotype was characterized by dystonia-parkinsonism, cognitive impairment, gait ataxia and apraxia, pyramidal signs. WES analysis allowed the identification of a compound heterozygosity for two nucleotide substitutions (c.1340G>A, p.R447H; c.790C>T, p.Q264X) affecting the TPP1 gene in the three affected siblings. Biochemical analyses demonstrated abrogated TPP1 catalytic activity in primary skin fibroblasts, but revealed residual activity in leukocytes. Our findings document that late infantile neuronal ceroid lipofuscinosis (CLN2), which is caused by TPP1 gene mutations, should be considered in the differential diagnosis of autosomal recessive dystonia-parkinsonism syndromes. The availability of enzyme replacement therapy and other therapeutic approaches for ceroid lipofuscinoses emphasizes the value of reaching an early diagnosis in patients with atypical and milder presentation of these disorders.
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Aminopeptidasas/genética , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/genética , Mutación/genética , Lipofuscinosis Ceroideas Neuronales , Serina Proteasas/genética , Biología Computacional , Electroencefalografía , Potenciales Evocados/fisiología , Femenino , Humanos , Italia , Masculino , Lipofuscinosis Ceroideas Neuronales/genética , Lipofuscinosis Ceroideas Neuronales/metabolismo , Lipofuscinosis Ceroideas Neuronales/patología , Hermanos , Piel/metabolismo , Piel/patología , Piel/ultraestructura , Tripeptidil Peptidasa 1 , Adulto JovenAsunto(s)
Programas de Gobierno , Gobierno , Política de Salud , Enfermedades Raras , Humanos , ItaliaRESUMEN
We report the draft genome sequence of the Stenotrophomonas maltophilia strain EPM1, found in association with a culture of Giardia duodenalis. The draft genome sequence of S. maltophilia strain EPM1, obtained with Roche 454 GS-FLX Titanium technology, is composed of 19 contigs totaling 4,785,869 bp, with a G+C content of 66.37%.
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This article reports on an association between Burkitt lymphoma and Noonan syndrome (NS) due to a RAF1 gene mutation. The patient was a 7-year-old boy with NS, who was included in the first series reporting the association between Noonan and RAF1, and who later presented with a 2-week history of asymptomatic unilateral tonsillar swelling and ipsilateral cervical lymphadenopathy. Histological and biological examinations of the tonsillar biopsy led to the diagnosis of Burkitt lymphoma. While there is a well-established association between NS and solid cell tumors, this is the first case described in the literature of Burkitt lymphoma in a patient with NS, and adds to the growing list of data supporting neoplasia's association with NS.
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Linfoma de Burkitt/genética , Síndrome de Noonan/genética , Proteínas Proto-Oncogénicas c-raf/genética , Sustitución de Aminoácidos , Linfoma de Burkitt/complicaciones , Linfoma de Burkitt/diagnóstico , Niño , Estudios de Asociación Genética , Humanos , Masculino , Mutación Missense , Síndrome de Noonan/complicaciones , Síndrome de Noonan/diagnósticoRESUMEN
The gene encoding the carbapenemase OXA-181 (an OXA-48 variant) was identified from a Citrobacter freundii isolate coproducing NDM-1. The whole sequence of plasmid pT-OXA-181 bearing the blaOXA-181 gene was determined and revealed a 84-kb mobilizable but non-self-conjugative IncT-type plasmid. It totally differs from the 7.6-kb ColE-type and blaOXA-181-bearing plasmid recently identified in a Klebsiella pneumoniae isolate. However, in both plasmids, insertion sequence ISEcp1 might have played a role in acquisition of the blaOXA-181 gene.
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Proteínas Bacterianas/metabolismo , Citrobacter freundii/enzimología , Plásmidos/genética , beta-Lactamasas/metabolismo , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Citrobacter freundii/efectos de los fármacos , Citrobacter freundii/genética , Datos de Secuencia Molecular , beta-Lactamasas/genéticaRESUMEN
OBJECTIVES: To characterize plasmid pNDM-MAR recovered from a Klebsiella pneumoniae isolate of sequence type (ST) 15 from Morocco, carrying the genes encoding the metallo-ß-lactamase NDM-1, the extended-spectrum ß-lactamase (ESBL) CTX-M-15 and the qnrB1 quinolone resistance determinant. METHODS: The plasmid DNA sequence was obtained by using the 454-Genome Sequencer FLX procedure on a library constructed from total plasmid DNA obtained from an Escherichia coli J53 transconjugant. Contig assembly and predicted gaps were confirmed and filled by PCR-based gap closure. RESULTS: Plasmid pNDM-MAR was 267â242 bp long and encoded 177 predicted proteins. It harboured novel replicons and transfer loci, defining a novel plasmid type within the IncH plasmid family. The bla(NDM-1) gene was flanked by genetic elements that are distinct from those observed in other bla(NDM-1)-positive plasmids, including the groES and groEL chaperonin genes. This plasmid harboured the ESBL gene bla(CTX-M-15) together with the quinolone resistance gene qnrB1. In addition, it harboured genes encoding resistance to tellurite, mercury, chloramphenicol and aminoglycosides. Interestingly, pNDM-MAR did not carry any 16S rRNA methylase gene, in contrast to other bla(NDM-1)-positive plasmids. CONCLUSIONS: This study underlines the diversity of genetic vehicles involved in the spread of the bla(NDM-1) gene. Plasmid pNDM-MAR differed significantly from all known bla(NDM-1)-bearing plasmids. Comparative analysis of the pNDM-MAR sequence identified a novel type of IncH plasmid.
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Proteínas Bacterianas/genética , ADN Bacteriano/química , ADN Bacteriano/genética , Klebsiella pneumoniae/genética , Plásmidos , beta-Lactamasas/genética , Conjugación Genética , Escherichia coli/genética , Variación Genética , Humanos , Infecciones por Klebsiella/microbiología , Datos de Secuencia Molecular , Marruecos , Análisis de Secuencia de ADNRESUMEN
Myhre syndrome is a developmental disorder characterized by reduced growth, generalized muscular hypertrophy, facial dysmorphism, deafness, cognitive deficits, joint stiffness, and skeletal anomalies. Here, by performing exome sequencing of a single affected individual and coupling the results to a hypothesis-driven filtering strategy, we establish that heterozygous mutations in SMAD4, which encodes for a transducer mediating transforming growth factor ß and bone morphogenetic protein signaling branches, underlie this rare Mendelian trait. Two recurrent de novo SMAD4 mutations were identified in eight unrelated subjects. Both mutations were missense changes altering Ile500 within the evolutionary conserved MAD homology 2 domain, a well known mutational hot spot in malignancies. Structural analyses suggest that the substituted residues are likely to perturb the binding properties of the mutant protein to signaling partners. Although SMAD4 has been established as a tumor suppressor gene somatically mutated in pancreatic, gastrointestinal, and skin cancers, and germline loss-of-function lesions and deletions of this gene have been documented to cause disorders that predispose individuals to gastrointestinal cancer and vascular dysplasias, the present report identifies a previously unrecognized class of mutations in the gene with profound impact on development and growth.
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Criptorquidismo/genética , Trastornos del Crecimiento/genética , Deformidades Congénitas de la Mano/genética , Hipertrofia/genética , Discapacidad Intelectual/genética , Artropatías/genética , Mutación Missense , Proteína Smad4/genética , Adolescente , Adulto , Secuencia de Bases , Preescolar , Exoma/genética , Facies , Femenino , Humanos , Masculino , Datos de Secuencia Molecular , Transducción de Señal/genéticaRESUMEN
A carbapenemase-resistant Klebsiella pneumoniae strain, clone ST258 producing KPC-3, was fully characterized. The entire plasmid content was investigated, thereby identifying plasmids of the IncFII(k) (two of them similar to pKPQIL and pKPN3, respectively), IncX, and ColE types, carrying a formidable set of resistance genes against toxic compounds, metals, and antimicrobial drugs and a novel iron(III) uptake system.
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Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana/genética , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/genética , Plásmidos/genética , Porinas/genética , beta-Lactamasas/genética , Antibacterianos/farmacología , Genes Bacterianos/genética , Variación Genética , Humanos , Hierro/metabolismo , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/efectos de los fármacos , Metales/farmacología , Pruebas de Sensibilidad Microbiana , Datos de Secuencia MolecularRESUMEN
Noonan syndrome, a developmental disorder characterized by congenital heart defects, reduced growth, facial dysmorphism and variable cognitive deficits, is caused by constitutional dysregulation of the RAS-MAPK signaling pathway. Here we report that germline NRAS mutations conferring enhanced stimulus-dependent MAPK activation account for some cases of this disorder. These findings provide evidence for an obligate dependency on proper NRAS function in human development and growth.
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Genes ras , Mutación , Síndrome de Noonan/genética , Proteínas ras/genética , Adolescente , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Células COS , Niño , Preescolar , Chlorocebus aethiops , Análisis Mutacional de ADN , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Síndrome de Noonan/metabolismo , Síndrome de Noonan/patología , Fosforilación , Estructura Terciaria de Proteína , Homología de Secuencia de Aminoácido , Transfección , Adulto Joven , Proteínas ras/químicaRESUMEN
Noonan syndrome (NS) is a genetically heterogeneous disorder caused most commonly by activating mutations in PTPN11. We report a patient with hypotonia, developmental delay and clinical features suggestive of NS. High-resolution chromosome analysis was normal, and sequence analyses of PTPN11, SOS1, KRAS, BRAF, RAF1, MEK, and MEK2 were also normal. Array CGH revealed a single copy gain of 9 BAC clones at 12q24.11q24.21 (8.98 Mb in size), which encompassed the PTPN11 locus at 12q24.13 and was confirmed by FISH analysis. Shchelochkov et al. [Shchelochkov et al. (2008); Am J Med Genet Part A 146A:1042-1048] reported a similar case and speculated that such duplications might account for 15-30% of NS cases with no detectable mutation in NS genes. We screened more than 250 NS cases without mutation in known NS disease-causing genes by quantitative PCR, and none of these studies produced results in the duplicated range. We also explored the possibility that de novo changes affecting the untranslated region (UTR) of the PTPN11 transcript might represent an alternative event involved in SHP2 enhanced expression. DHPLC analysis and direct sequencing of the entire 3' UTR in 36 NS patients without mutation in known genes did not show any disease-associated variant. These findings indicate that duplications of PTPN11 represent an uncommon cause of NS, and functionally relevant variations within the 3'UTR of the gene do not appear to play a major role in NS. However, recurrent observations of NS in individuals with duplications involving the PTPN11 locus suggest that increased dosage of SHP2 may have dysregulating effects on intracellular signaling.