228 research outputs found

    Transcriptional Hallmarks of Noonan Syndrome and Noonan-Like Syndrome with Loose Anagen Hair

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    Noonan syndrome (NS) is among the most common nonchromosomal disorders affecting development and growth. NS is genetically heterogeneous, being caused by germline mutations affecting various genes implicated in the RAS signaling network. This network transduces extracellular signals into intracellular biochemical and transcriptional responses controlling cell proliferation, differentiation, metabolism, and senescence. To explore the transcriptional consequences of NS-causing mutations, we performed global mRNA expression profiling on peripheral blood mononuclear cells obtained from 23 NS patients carrying heterozygous mutations in PTPN11 or SOS1. Gene expression profiling was also resolved in five subjects with Noonan-like syndrome with loose anagen hair (NS/LAH), a condition clinically related to NS and caused by an invariant mutation in SHOC2. Robust transcriptional signatures were found to specifically discriminate each of the three mutation groups from 21 age- and sex-matched controls. Despite the only partial overlap in terms of gene composition, the three signatures showed a notable concordance in terms of biological processes and regulatory circuits affected. These data establish expression profiling of peripheral blood mononuclear cells as a powerful tool to appreciate differential perturbations driven by germline mutations of transducers involved in RAS signaling and to dissect molecular mechanisms underlying NS and other RASopathies. Hum Mutat 33:703–709, 2012. © 2012 Wiley Periodicals, Inc

    Mutations in KCNK4 that Affect Gating Cause a Recognizable Neurodevelopmental Syndrome

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    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

    Hepatocellular carcinoma in chronic HBV-HCV co-infection is correlated to fibrosis and disease duration

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    Hepatocellular carcinoma (HCC) is a development of severe liver disease frequently due to HBV and/or HCV infection. The aim of this retrospective study was to evaluate the development of HCC in patients with HBV-HCV chronic infection compared with patients with single HBV or HCV infection and the viral and host factors correlated to HCC in co-infected patients. We studied 268 patients with histology proven chronic hepatitis: 56 had HBV-HCV co-infection (HBV-HCV group), 46 had HBV infection (HBV group) and 166 had HCV infection (HCV group). Patients were followed up for at least 3 years. Viral and host factors were studied. HCC was more frequent in HBV-HCV group (14%) compared with HBV (2%, p = 0.006) and HCV monoinfected (4%, p = 0.006). The Mantel-Haenszel test used to investigate the relationship between HBV-HCV co-infection and development of HCC indicated an association between development of HCC and HBV-HCV co-infection (p < 0.001). In the HBV-HCV group, patients with HCC were significantly older (p = 0.000), had longer disease duration (p = 0.001), higher blood glucose levels (p = 0.001), lower levels of steatosis (p = 0.02), higher levels of fibrosis (p = 0.000), higher HCV RNA (p = 0.01) than those without HCC. ALT, lipid profile, PNPLA3 variant distribution and HBV viral load did not differ among co-infected patients with or without HCC. In conclusion HCC was more frequent in our patients with HBV-HCV co-infection, than in those with HBV or HCV mono-infection; possible associated risk factors for HCC development seem a long duration of disease, high levels of fibrosis and carbohydrate intolerance

    Mutations impairing GSK3-mediated MAF phosphorylation cause cataract, deafness, intellectual disability, seizures, and a down syndrome-like facies

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    Transcription factors operate in developmental processes to mediate inductive events and cell competence, and perturbation of their function or regulation can dramatically affect morphogenesis, organogenesis, and growth. We report that a narrow spectrum of amino-acid substitutions within the transactivation domain of the v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog (MAF), a leucine zipper-containing transcription factor of the AP1 superfamily, profoundly affect development. Seven different de novo missense mutations involving conserved residues of the four GSK3 phosphorylation motifs were identified in eight unrelated individuals. The distinctive clinical phenotype, for which we propose the eponym Aymé-Gripp syndrome, is not limited to lens and eye defects as previously reported for MAF/Maf loss of function but includes sensorineural deafness, intellectual disability, seizures, brachycephaly, distinctive flat facial appearance, skeletal anomalies, mammary gland hypoplasia, and reduced growth. Disease-causing mutations were demonstrated to impair proper MAF phosphorylation, ubiquitination and proteasomal degradation, perturbed gene expression in primary skin fibroblasts, and induced neurodevelopmental defects in an in vivo model. Our findings nosologically and clinically delineate a previously poorly understood recognizable multisystem disorder, provide evidence for MAF governing a wider range of developmental programs than previously appreciated, and describe a novel instance of protein dosage effect severely perturbing developmen

    Children with special health care needs attending emergency department in Italy: analysis of 3479 cases

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    Background: Although children with special health care needs (CSHCN) represent a minority of the population, they go through more hospitalizations, more admissions to the Emergency Department (ED), and receive a major number of medical prescriptions, in comparison to general pediatric population. Objectives of the study were to determine the reasons for admission to the ED in Italian CSHCN, and to describe the association between patient's demographic data, clinical history, and health services requirements. Methods: Ad hoc web site was created to collect retrospective data of 3479 visits of CSHCN to the ED in 58 Italian Hospitals. Results: Seventy-two percent of patients admitted to ED were affected by a previously defined medical condition. Most of the ED admissions were children with syndromic conditions (54%). 44.2% of the ED admissions were registered during the night-time and/or at the weekends. The hospitalization rate was of 45.6% among patients admitted to the ED. The most common reason for admission to the ED was the presence of respiratory symptoms (26.6%), followed by gastrointestinal problems (21.3%) and neurological disorders (18.2%). 51.4% of the access were classified as 'urgent', with a red/yellow triage code. Considering the type of ED, 61.9% of the visits were conducted at the Pediatric EDs (PedEDs), 33.5% at the Functional EDs (FunEDs) and 4.6% at the Dedicated EDs (DedEDs). Patients with more complex clinical presentation were more likely to be evaluated at the PedEDs. CSHCN underwent to a higher number of medical procedures at the PedEDs, more in comparison to other EDs. Children with medical devices were directed to a PedED quite exclusively when in need for medical attention. Subjects under multiple anti-epileptic drug therapy attended to PedEDs or FunEDs generally. Patients affected by metabolic diseases were more likely to look for medical attention at FunEDs. Syndromic patients mostly required medical attention at the DedEDs. Conclusions: Access of CSHCN to an ED is not infrequent. For this reason, it is fundamental for pediatricians working in any kind of ED to increase their general knowledge about CHSCN and to gain expertise in the management of such patients and their related medical complexity

    Long-term outcomes of pediatric infections: from traditional infectious diseases to long covid

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    : There is limited evidence available on the long-term impact of SARS-CoV-2 infection in children. In this article, the authors&nbsp;analyze the&nbsp;recent evidence on pediatric long covid and lessons learnt from a pediatric post-covid unit in Rome, Italy. To gain a better understanding of the concerns raised by parents and physicians in relation to the potential long-term consequences of this novel infection, it is important to recognize that long-term effect&nbsp;of a&nbsp;post-infectious disease is not a new phenomenon
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