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1.
J Am Coll Cardiol ; 74(3): 346-358, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31319917

RESUMO

BACKGROUND: Arrhythmogenic cardiomyopathy (ACM) is a variably penetrant disease increasingly identified in young patients. OBJECTIVES: This study sought to describe the diverse phenotype, genotype, and outcomes in pediatric and adolescent patients. METHODS: Records from 1999 to 2016 were reviewed for individuals age <21 years with a consistent personal or family history. Patients were categorized by right ventricular (RV), left dominant (LD), or biventricular subtypes using 2010 Task Force Criteria or proposed features of LD disease, encompassing electrocardiographic, structural, histological, and arrhythmic characteristics. Genetic variants classified as pathogenic and/or likely pathogenic by 2015 American College of Medical Genetics and Genomics criteria in recognized disease-associated genes were included. RESULTS: Manifest disease was evident in 32 patients (age 15.1 ± 3.8 years), of whom 22 were probands, including 16 RV, 7 LD, and 9 biventricular ACM. Nondiagnostic features were seen in 5 of 15 family members. RV disease was associated with cardiac arrest and ventricular tachycardia (p = 0.02) and prevalence of PKP2 variants (p < 0.01), whereas biventricular disease was associated with a younger age of onset (p = 0.02). LD ACM was associated with variants in DSP and LMNA, and biventricular ACM with more a diverse etiology in desmosomal genes. Cardiac arrest was observed in 5 probands (age 15.3 ± 1.9 years) and ventricular tachycardia in 10 (age 16.6 ± 2.7 years), 6 probands, and 4 family members. Features suggestive of myocardial inflammation were seen in 6 patients, with ventricular tachycardia and/or cardiac arrest in 3 patients. Cardiac transplantation was performed in 10 patients. There were no deaths. In RV and biventricular disease, electrocardiographic preceded imaging features, whereas the reverse was seen in LD disease. CONCLUSIONS: ACM in the young has highly varied phenotypic expression incorporating life-threatening arrhythmia, heart failure, and myocardial inflammation. Increased awareness of early onset, aggressive disease has important implications for patient management and familial screening.

2.
Circulation ; 140(5): 390-404, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31311300

RESUMO

BACKGROUND: Modeling of human arrhythmias with induced pluripotent stem cell-derived cardiomyocytes has focused on single-cell phenotypes. However, arrhythmias are the emergent properties of cells assembled into tissues, and the impact of inherited arrhythmia mutations on tissue-level properties of human heart tissue has not been reported. METHODS: Here, we report an optogenetically based, human engineered tissue model of catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited arrhythmia caused by mutation of the cardiac ryanodine channel and triggered by exercise. We developed a human induced pluripotent stem cell-derived cardiomyocyte-based platform to study the tissue-level properties of engineered human myocardium. We investigated pathogenic mechanisms in CPVT by combining this novel platform with genome editing. RESULTS: In our model, CPVT tissues were vulnerable to developing reentrant rhythms when stimulated by rapid pacing and catecholamine, recapitulating hallmark features of the disease. These conditions elevated diastolic Ca2+ levels and increased temporal and spatial dispersion of Ca2+ wave speed, creating a vulnerable arrhythmia substrate. Using Cas9 genome editing, we pinpointed a single catecholamine-driven phosphorylation event, ryanodine receptor-serine 2814 phosphorylation by Ca2+/calmodulin-dependent protein kinase II, that is required to unmask the arrhythmic potential of CPVT tissues. CONCLUSIONS: Our study illuminates the molecular and cellular pathogenesis of CPVT and reveals a critical role of calmodulin-dependent protein kinase II-dependent reentry in the tissue-scale mechanism of this disease. We anticipate that this approach will be useful for modeling other inherited and acquired cardiac arrhythmias.

3.
Cereb Cortex ; 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31216004

RESUMO

Neurodevelopmental abnormalities are the most common noncardiac complications in patients with congenital heart disease (CHD). Prenatal brain abnormalities may be due to reduced oxygenation, genetic factors, or less commonly, teratogens. Understanding the contribution of these factors is essential to improve outcomes. Because primary sulcal patterns are prenatally determined and under strong genetic control, we hypothesized that they are influenced by genetic variants in CHD. In this study, we reveal significant alterations in sulcal patterns among subjects with single ventricle CHD (n = 115, 14.7 ± 2.9 years [mean ± standard deviation]) compared with controls (n = 45, 15.5 ± 2.4 years) using a graph-based pattern-analysis technique. Among patients with CHD, the left hemisphere demonstrated decreased sulcal pattern similarity to controls in the left temporal and parietal lobes, as well as the bilateral frontal lobes. Temporal and parietal lobes demonstrated an abnormally asymmetric left-right pattern of sulcal basin area in CHD subjects. Sulcal pattern similarity to control was positively correlated with working memory, processing speed, and executive function. Exome analysis identified damaging de novo variants only in CHD subjects with more atypical sulcal patterns. Together, these findings suggest that sulcal pattern analysis may be useful in characterizing genetically influenced, atypical early brain development and neurodevelopmental risk in subjects with CHD.

4.
Circulation ; 140(3): 207-224, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31163979

RESUMO

BACKGROUND: More than 90% of individuals with Noonan syndrome (NS) with mutations clustered in the CR2 domain of RAF1 present with severe and often lethal hypertrophic cardiomyopathy (HCM). The signaling pathways by which NS RAF1 mutations promote HCM remain elusive, and so far, there is no known treatment for NS-associated HCM. METHODS: We used patient-derived RAF1S257L/+ and CRISPR-Cas9-generated isogenic control inducible pluripotent stem cell (iPSC)-derived cardiomyocytes to model NS RAF1-associated HCM and to further delineate the molecular mechanisms underlying the disease. RESULTS: We show that mutant iPSC-derived cardiomyocytes phenocopy the pathology seen in hearts of patients with NS by exhibiting hypertrophy and structural defects. Through pharmacological and genetic targeting, we identify 2 perturbed concomitant pathways that, together, mediate HCM in RAF1 mutant iPSC-derived cardiomyocytes. Hyperactivation of mitogen-activated protein kinase kinase 1/2 (MEK1/2), but not extracellular regulated kinase 1/2, causes myofibrillar disarray, whereas the enlarged cardiomyocyte phenotype is a direct consequence of increased extracellular regulated kinase 5 (ERK5) signaling, a pathway not previously known to be involved in NS. RNA-sequencing reveals genes with abnormal expression in RAF1 mutant iPSC-derived cardiomyocytes and identifies subsets of genes dysregulated by aberrant MEK1/2 or ERK5 pathways that could contribute to the NS-associated HCM. CONCLUSIONS: Taken together, the results of our study identify the molecular mechanisms by which NS RAF1 mutations cause HCM and reveal downstream effectors that could serve as therapeutic targets for treatment of NS and perhaps other, more common, congenital HCM disorders.

6.
Stem Cell Res ; 34: 101374, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30640061

RESUMO

Noonan syndrome with multiple lentigines (NSML), formerly known as LEOPARD Syndrome, is a rare autosomal dominant disorder. Approximately 90% of NSML cases are caused by missense mutations in the PTPN11 gene which encodes the protein tyrosine phosphatase SHP2. A human induced pluripotent stem cell (iPSC) line was generated using peripheral blood mononuclear cells (PBMCs) from a patient with NSML that carries a gene mutation of p.Q510P on the PTPN11 gene using non-integrating Sendai virus technique. This iPSC line offers a useful resource to study the disease pathophysiology and a cell-based model for drug development to treat NSML.


Assuntos
Técnicas de Cultura de Células/métodos , Células-Tronco Pluripotentes Induzidas/patologia , Síndrome LEOPARD/genética , Síndrome LEOPARD/patologia , Mutação/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Adolescente , Sequência de Bases , Linhagem Celular , Feminino , Humanos
8.
Am J Hum Genet ; 103(5): 786-793, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30343942

RESUMO

PCGF2 encodes the polycomb group ring finger 2 protein, a transcriptional repressor involved in cell proliferation, differentiation, and embryogenesis. PCGF2 is a component of the polycomb repressive complex 1 (PRC1), a multiprotein complex which controls gene silencing through histone modification and chromatin remodelling. We report the phenotypic characterization of 13 patients (11 unrelated individuals and a pair of monozygotic twins) with missense mutations in PCGF2. All the mutations affected the same highly conserved proline in PCGF2 and were de novo, excepting maternal mosaicism in one. The patients demonstrated a recognizable facial gestalt, intellectual disability, feeding problems, impaired growth, and a range of brain, cardiovascular, and skeletal abnormalities. Computer structural modeling suggests the substitutions alter an N-terminal loop of PCGF2 critical for histone biding. Mutant PCGF2 may have dominant-negative effects, sequestering PRC1 components into complexes that lack the ability to interact efficiently with histones. These findings demonstrate the important role of PCGF2 in human development and confirm that heterozygous substitutions of the Pro65 residue of PCGF2 cause a recognizable syndrome characterized by distinctive craniofacial, neurological, cardiovascular, and skeletal features.

9.
PLoS One ; 13(1): e0191319, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29351346

RESUMO

The Pediatric Cardiac Genomics Consortium (PCGC) designed the Congenital Heart Disease Genetic Network Study to provide phenotype and genotype data for a large congenital heart defects (CHDs) cohort. This article describes the PCGC cohort, overall and by major types of CHDs (e.g., conotruncal defects) and subtypes of conotrucal heart defects (e.g., tetralogy of Fallot) and left ventricular outflow tract obstructions (e.g., hypoplastic left heart syndrome). Cases with CHDs were recruited through ten sites, 2010-2014. Information on cases (N = 9,727) and their parents was collected through interviews and medical record abstraction. Four case characteristics, eleven parental characteristics, and thirteen parent-reported neurodevelopment outcomes were summarized using counts and frequencies and compared across CHD types and subtypes. Eleven percent of cases had a genetic diagnosis. Among cases without a genetic diagnosis, the majority had conotruncal heart defects (40%) or left ventricular outflow tract obstruction (21%). Across CHD types, there were significant differences (p<0.05) in the distribution of all four case characteristics (e.g., sex), four parental characteristics (e.g., maternal pregestational diabetes), and five neurodevelopmental outcomes (e.g., learning disabilities). Several characteristics (e.g., sex) were also significantly different across CHD subtypes. The PCGC cohort is one of the largest CHD cohorts available for the study of genetic determinants of risk and outcomes. The majority of cases do not have a genetic diagnosis. This description of the PCGC cohort, including differences across CHD types and subtypes, provides a reference work for investigators who are interested in collaborating with or using publically available resources from the PCGC.


Assuntos
Redes Reguladoras de Genes , Cardiopatias Congênitas/genética , Adulto , Estudos de Coortes , Feminino , Cardiopatias Congênitas/fisiopatologia , Humanos , Masculino , Fenótipo
10.
Circ Cardiovasc Genet ; 10(5)2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29025761

RESUMO

BACKGROUND: The 22q11.2 deletion syndrome (22q11.2DS; DiGeorge syndrome/velocardiofacial syndrome) occurs in 1 of 4000 live births, and 60% to 70% of affected individuals have congenital heart disease, ranging from mild to severe. In our cohort of 1472 subjects with 22q11.2DS, a total of 62% (n=906) have congenital heart disease and 36% (n=326) of these have tetralogy of Fallot (TOF), comprising the largest subset of severe congenital heart disease in the cohort. METHODS AND RESULTS: To identify common genetic variants associated with TOF in individuals with 22q11.2DS, we performed a genome-wide association study using Affymetrix 6.0 array and imputed genotype data. In our cohort, TOF was significantly associated with a genotyped single-nucleotide polymorphism (rs12519770, P=2.98×10-8) in an intron of the adhesion GPR98 (G-protein-coupled receptor V1) gene on chromosome 5q14.3. There was also suggestive evidence of association between TOF and several additional single-nucleotide polymorphisms in this region. Some genome-wide significant loci in introns or noncoding regions could affect regulation of genes nearby or at a distance. On the basis of this possibility, we examined existing Hi-C chromatin conformation data to identify genes that might be under shared transcriptional regulation within the region on 5q14.3. There are 6 genes in a topologically associated domain of chromatin with GPR98, including MEF2C (Myocyte-specific enhancer factor 2C). MEF2C is the only gene that is known to affect heart development in mammals and might be of interest with respect to 22q11.2DS. CONCLUSIONS: In conclusion, common variants may contribute to TOF in 22q11.2DS and may function in cardiac outflow tract development.


Assuntos
Síndrome de DiGeorge/genética , Estudo de Associação Genômica Ampla , Receptores Acoplados a Proteínas-G/genética , Tetralogia de Fallot/genética , Cromatina/metabolismo , Cromossomos Humanos Par 5 , Síndrome de DiGeorge/complicações , Loci Gênicos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Desequilíbrio de Ligação , Fatores de Transcrição MEF2/genética , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Polimorfismo de Nucleotídeo Único , Receptores Acoplados a Proteínas-G/metabolismo , Análise de Sequência de DNA , Tetralogia de Fallot/complicações
12.
Nat Genet ; 49(11): 1593-1601, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28991257

RESUMO

Congenital heart disease (CHD) is the leading cause of mortality from birth defects. Here, exome sequencing of a single cohort of 2,871 CHD probands, including 2,645 parent-offspring trios, implicated rare inherited mutations in 1.8%, including a recessive founder mutation in GDF1 accounting for ∼5% of severe CHD in Ashkenazim, recessive genotypes in MYH6 accounting for ∼11% of Shone complex, and dominant FLT4 mutations accounting for 2.3% of Tetralogy of Fallot. De novo mutations (DNMs) accounted for 8% of cases, including ∼3% of isolated CHD patients and ∼28% with both neurodevelopmental and extra-cardiac congenital anomalies. Seven genes surpassed thresholds for genome-wide significance, and 12 genes not previously implicated in CHD had >70% probability of being disease related. DNMs in ∼440 genes were inferred to contribute to CHD. Striking overlap between genes with damaging DNMs in probands with CHD and autism was also found.


Assuntos
Transtorno Autístico/genética , Miosinas Cardíacas/genética , Predisposição Genética para Doença , Fator 1 de Diferenciação de Crescimento/genética , Cardiopatias Congênitas/genética , Cadeias Pesadas de Miosina/genética , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/genética , Adulto , Transtorno Autístico/patologia , Estudos de Casos e Controles , Criança , Exoma , Feminino , Expressão Gênica , Estudo de Associação Genômica Ampla , Cardiopatias Congênitas/patologia , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Homozigoto , Humanos , Masculino , Mutação , Linhagem , Risco
13.
Congenit Heart Dis ; 12(4): 475-483, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28719049

RESUMO

OBJECTIVE: To describe a group of children with co-incident pulmonary vein stenosis and Smith-Lemli-Opitz syndrome and to generate hypotheses as to the shared pathogenesis of these disorders. DESIGN: Retrospective case series. PATIENTS: Five subjects in a pulmonary vein stenosis cohort of 170 subjects were diagnosed with Smith-Lemli-Opitz syndrome soon after birth. RESULTS: All five cases were diagnosed with Smith-Lemli-Opitz syndrome within 6 weeks of life, with no family history of either disorder. All cases had pathologically elevated 7-dehydrocholesterol levels and two of the five cases had previously reported pathogenic 7-dehydrocholesterol reductase mutations. Smith-Lemli-Opitz syndrome severity scores ranged from mild to classical (2-7). Gestational age at birth ranged from 35 to 39 weeks. Four of the cases were male by karyotype. Pulmonary vein stenosis was diagnosed in all cases within 2 months of life, earlier than most published cohorts. All cases progressed to bilateral disease and three cases developed atresia of at least one vein. Despite catheter and surgical interventions, all subjects' pulmonary vein stenosis rapidly recurred and progressed. Three of the subjects died, at 2 months, 3 months, and 11 months. Survival at 16 months after diagnosis was 43%. CONCLUSIONS: Patients with pulmonary vein stenosis who have a suggestive syndromic presentation should be screened for Smith-Lemli-Opitz syndrome with easily obtainable serum sterol tests. Echocardiograms should be obtained in all newly diagnosed patients with Smith-Lemli-Opitz syndrome, with a low threshold for repeating the study if new respiratory symptoms of uncertain etiology arise. Further studies into the pathophysiology of pulmonary vein stenosis should consider the role of cholesterol-based signaling pathways in the promotion of intimal proliferation.


Assuntos
Anormalidades Múltiplas , Síndrome de Smith-Lemli-Opitz/diagnóstico , Estenose de Veia Pulmonar/diagnóstico , Angiografia , Pré-Escolar , Ecocardiografia , Evolução Fatal , Feminino , Seguimentos , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos , Estenose de Veia Pulmonar/congênito
14.
Curr Opin Pediatr ; 29(5): 529-533, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28719389

RESUMO

PURPOSE OF REVIEW: Neurodevelopmental impairment is common in children with moderate to severe congenital heart disease (CHD). As children live longer and healthier lives, research has focused on identifying causes of neurodevelopmental morbidity that significantly impact long-term quality of life. This review will address the role of genetic factors in predicting neurodevelopmental outcome in CHD. RECENT FINDINGS: A robust literature suggests that among children with various forms of CHD, those with known genetic/extracardiac anomalies are at highest risk of neurodevelopmental impairment. Advances in genetic technology have identified genetic causes of CHD in an increasing percentage of patients. Further, emerging data suggest substantial overlap between mutations in children with CHD and those that have previously been associated with neurodevelopmental disorders. SUMMARY: Innate and patient factors appear to be more important in predicting neurodevelopmental outcome than medical/surgical variables. Future research is needed to establish a broader understanding of the mutations that contribute to neurodevelopmental disorders and the variations in expressivity and penetrance.


Assuntos
Predisposição Genética para Doença , Cardiopatias Congênitas/complicações , Transtornos do Neurodesenvolvimento/genética , Encéfalo/embriologia , Coração/embriologia , Cardiopatias Congênitas/genética , Humanos , Transtornos do Neurodesenvolvimento/complicações , Fatores de Risco
16.
Hum Genet ; 135(3): 273-85, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26742502

RESUMO

The 22q11.2 deletion syndrome (22q11DS; velocardiofacial/DiGeorge syndrome; VCFS/DGS; MIM #192430; 188400) is the most common microdeletion syndrome. The phenotypic presentation of 22q11DS is highly variable; approximately 60-75 % of 22q11DS patients have been reported to have a congenital heart defect (CHD), mostly of the conotruncal type, and/or aortic arch defect. The etiology of the cardiac phenotypic variability is not currently known for the majority of patients. We hypothesized that rare copy number variants (CNVs) outside the 22q11.2 deleted region may modify the risk of being born with a CHD in this sensitized population. Rare CNV analysis was performed using Affymetrix SNP Array 6.0 data from 946 22q11DS subjects with CHDs (n = 607) or with normal cardiac anatomy (n = 339). Although there was no significant difference in the overall burden of rare CNVs, an overabundance of CNVs affecting cardiac-related genes was detected in 22q11DS individuals with CHDs. When the rare CNVs were examined with regard to gene interactions, specific cardiac networks, such as Wnt signaling, appear to be overrepresented in 22q11DS CHD cases but not 22q11DS controls with a normal heart. Collectively, these data suggest that CNVs outside the 22q11.2 region may contain genes that modify risk for CHDs in some 22q11DS patients.


Assuntos
Variações do Número de Cópias de DNA , Síndrome de DiGeorge/genética , Cardiopatias Congênitas/genética , Deleção Cromossômica , Cromossomos Humanos Par 22/genética , Síndrome de DiGeorge/diagnóstico , Técnicas de Genotipagem , Cardiopatias Congênitas/diagnóstico , Humanos
17.
J Am Heart Assoc ; 4(12)2015 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-26667085

RESUMO

BACKGROUND: Few studies have described the neuropsychological outcomes and frequency of structural brain or genetic abnormalities in adolescents with single ventricle who underwent the Fontan procedure. METHODS AND RESULTS: In a cross-sectional, single-center study, we enrolled 156 subjects with single ventricle, mean age 14.5±2.9 years, who had undergone the Fontan procedure. Scores in the entire cohort on a standard battery of neuropsychological tests were compared with those of normative populations or to those of a group of 111 locally recruited healthy adolescents. They also underwent brain magnetic resonance imaging and were evaluated by a clinical geneticist. Genetic abnormalities were definite in 16 subjects (10%) and possible in 49 subjects (31%). Mean Full-Scale IQ was 91.6±16.8, mean Reading Composite score was 91.9±17.2, and mean Mathematics Composite score was 92.0±22.9, each significantly lower than the population means of 100±15. Mean scores on other neuropsychological tests were similarly lower than population norms. In multivariable models, risk factors for worse neuropsychological outcomes were longer total support and circulatory arrest duration at first operation, presence of a genetic abnormality, more operations and operative complications, more catheterization complications, and seizure history. The frequency of any abnormality on magnetic resonance imaging was 11 times higher among Fontan adolescents than referents (66% versus 6%); 19 (13%) patients had evidence of a stroke, previously undiagnosed in 7 patients (40%). CONCLUSIONS: The neuropsychological deficits and high frequencies of structural brain abnormalities in adolescents who underwent the Fontan procedure highlight the need for research on interventions to improve the long-term outcomes in this high-risk group.


Assuntos
Encéfalo/patologia , Transtornos Cognitivos/etiologia , Técnica de Fontan , Ventrículos do Coração/anormalidades , Adolescente , Criança , Estudos Transversais , Feminino , Técnica de Fontan/efeitos adversos , Doenças Genéticas Inatas/complicações , Doenças Genéticas Inatas/genética , Ventrículos do Coração/cirurgia , Humanos , Imagem por Ressonância Magnética , Masculino , Neuroimagem , Testes Neuropsicológicos , Adulto Jovem
18.
Prog Pediatr Cardiol ; 39(1): 13-19, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-26380542

RESUMO

Noonan syndrome and related disorders (Noonan syndrome with multiple lentigines, Costello syndrome, cardiofaciocutaneous syndrome, Noonan syndrome with loose anagen hair, and other related traits) are autosomal dominant traits. Mutations causing these disorders alter proteins relevant for signaling through RAS. Thus, these traits are now collectively called the RASopathies. While the RASopathies have pleiomorphic features, this review will focus on the hypertrophic cardiomyopathy observed in varying percentages of all of these traits. In addition, inherited abnormalities in one pathway gene, RAF1, cause pediatric-onset dilated cardiomyopathy. The pathogeneses for the RASopathy-associated cardiomyopathies are being elucidated, principally using animal models, leading to genotype-specific insights into how signal transduction is perturbed. Based on those findings, small molecule therapies seem possible for RASopathy-associated cardiomyopathies.

19.
Hum Mutat ; 36(11): 1080-7, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26173643

RESUMO

The RASopathies constitute a family of autosomal-dominant disorders whose major features include facial dysmorphism, cardiac defects, reduced postnatal growth, variable cognitive deficits, ectodermal and skeletal anomalies, and susceptibility to certain malignancies. Noonan syndrome (NS), the commonest RASopathy, is genetically heterogeneous and caused by functional dysregulation of signal transducers and regulatory proteins with roles in the RAS/extracellular signal-regulated kinase (ERK) signal transduction pathway. Mutations in known disease genes account for approximately 80% of affected individuals. Here, we report that missense mutations altering Son of Sevenless, Drosophila, homolog 2 (SOS2), which encodes a RAS guanine nucleotide exchange factor, occur in a small percentage of subjects with NS. Four missense mutations were identified in five unrelated sporadic cases and families transmitting NS. Disease-causing mutations affected three conserved residues located in the Dbl homology (DH) domain, of which two are directly involved in the intramolecular binding network maintaining SOS2 in its autoinhibited conformation. All mutations were found to promote enhanced signaling from RAS to ERK. Similar to NS-causing SOS1 mutations, the phenotype associated with SOS2 defects is characterized by normal development and growth, as well as marked ectodermal involvement. Unlike SOS1 mutations, however, those in SOS2 are restricted to the DH domain.


Assuntos
Estudos de Associação Genética , Mutação , Síndrome de Noonan/genética , Domínios e Motivos de Interação entre Proteínas/genética , Proteínas Son Of Sevenless/genética , Adolescente , Adulto , Alelos , Substituição de Aminoácidos , Criança , Análise Mutacional de DNA , Exoma , Facies , Feminino , Genótipo , Humanos , Masculino , Modelos Moleculares , Síndrome de Noonan/diagnóstico , Fenótipo , Conformação Proteica , Proteínas Son Of Sevenless/química , Adulto Jovem
20.
Am J Hum Genet ; 96(5): 753-64, 2015 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-25892112

RESUMO

The 22q11.2 deletion syndrome (22q11DS; velocardiofacial/DiGeorge syndrome; VCFS/DGS) is the most common microdeletion syndrome and the phenotypic presentation is highly variable. Approximately 65% of individuals with 22q11DS have a congenital heart defect (CHD), mostly of the conotruncal type, and/or an aortic arch defect. The etiology of this phenotypic variability is not currently known. We hypothesized that copy-number variants (CNVs) outside the 22q11.2 deleted region might increase the risk of being born with a CHD in this sensitized population. Genotyping with Affymetrix SNP Array 6.0 was performed on two groups of subjects with 22q11DS separated by time of ascertainment and processing. CNV analysis was completed on a total of 949 subjects (cohort 1, n = 562; cohort 2, n = 387), 603 with CHDs (cohort 1, n = 363; cohort 2, n = 240) and 346 with normal cardiac anatomy (cohort 1, n = 199; cohort 2, n = 147). Our analysis revealed that a duplication of SLC2A3 was the most frequent CNV identified in the first cohort. It was present in 18 subjects with CHDs and 1 subject without (p = 3.12 × 10(-3), two-tailed Fisher's exact test). In the second cohort, the SLC2A3 duplication was also significantly enriched in subjects with CHDs (p = 3.30 × 10(-2), two-tailed Fisher's exact test). The SLC2A3 duplication was the most frequent CNV detected and the only significant finding in our combined analysis (p = 2.68 × 10(-4), two-tailed Fisher's exact test), indicating that the SLC2A3 duplication might serve as a genetic modifier of CHDs and/or aortic arch anomalies in individuals with 22q11DS.


Assuntos
Variações do Número de Cópias de DNA/genética , Síndrome de DiGeorge/genética , Transportador de Glucose Tipo 3/genética , Cardiopatias Congênitas/genética , Adulto , Aorta Torácica/fisiopatologia , Síndrome de DiGeorge/fisiopatologia , Feminino , Genótipo , Cardiopatias Congênitas/fisiopatologia , Humanos , Masculino , Polimorfismo de Nucleotídeo Único
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