RASopathies comprise a group of disorders clinically characterized by short stature, heart defects, facial dysmorphism, and varying degrees of intellectual disability and cancer predisposition. They are caused by germline variants in genes encoding key components or modulators of the highly conserved RAS-MAPK signalling pathway that lead to dysregulation of cell signal transmission. Germline changes in the genes encoding members of the RAS subfamily of GTPases are rare and associated with variable phenotypes of the RASopathy spectrum, ranging from Costello syndrome (HRAS variants) to Noonan and Cardiofaciocutaneous syndromes (KRAS variants). A small number of RASopathy cases with disease-causing germline NRAS alterations have been reported. Affected individuals exhibited features fitting Noonan syndrome, and the observed germline variants differed from the typical oncogenic NRAS changes occurring as somatic events in tumours. Here we describe 19 new cases with RASopathy due to disease-causing variants in NRAS. Importantly, four of them harbored missense changes affecting Gly12, which was previously described to occur exclusively in cancer. The phenotype in our cohort was variable but well within the RASopathy spectrum. Further, one of the patients (c.35G>A; p.(Gly12Asp)) had a myeloproliferative disorder, and one subject (c.34G>C; p.(Gly12Arg)) exhibited an uncharacterized brain tumour. With this report, we expand the genotype and phenotype spectrum of RASopathy-associated germline NRAS variants and provide evidence that NRAS variants do not spare the cancer-associated mutation hotspots.

Background Carbapenem-resistant Enterobacteriaceae (CRE) are an emerging problem in the paediatric population worldwide with high mortality rates in bloodstream infection (BSI). Objectives To evaluate predictors of 30 day mortality in CRE BSI in a paediatric cohort. Methods A retrospective observational single-centre study (December 2005–August 2018) was conducted. Cases of CRE BSI in children 0 to 16 years were included. Microbiological identification (MALDI Biotyper) and antimicrobial susceptibility testing (Vitek2® and MicroScan panel NBC44) according to EUCAST breakpoints were performed. PCR OXVIKP® was used to confirm carbapenemase genes (OXA-48, VIM, KPC, NDM). Demographic characteristics, underlying diseases, source of bacteraemia, antimicrobial therapy and outcomes were collected from medical records. Survival analysis to establish predictors of 30 day mortality was performed. Results Thirty-eight cases were included; 76.3% were hospital-acquired infections and 23.7% related to healthcare. All patients had at least one underlying comorbidity and 52.6% were recipients of an organ transplant. VIM carbapenemase was the predominant mechanism (92.1%). Previous CRE colonization or infection rate was 52.6%. Intestinal tract (26.3%) and vascular catheter (21.1%) were the most common sources of infection. Crude mortality within 30 days was 18.4% (7/38); directly related 30 day mortality was 10.5%. Conditions associated with an increment in 30 day mortality were intensive care admission and inadequate empirical therapy (P < 0.05). Combination-antibiotic targeted treatment and a low meropenem MIC were not related to improved survival. Conclusions CRE BSI mortality rate is high. The most important factor related to 30 day survival in our CRE BSI cohort in children was empirical treatment that included at least one active antibiotic.

High-density multielectrode mapping is associated with a significant reduction of procedural and mapping times and a significant increase of mapping density without affecting outcomes in patients with scar-related VT.

Neuroblastoma causes 15% of cancer mortality in children. High risk neuroblastoma has poor prognosis, with high relapse rate and mortality despite multimodal treatment. 123-I-meta-iodo-benzyl-guanidine (mIBG) scintigraphy is one of the current standard diagnostic procedures in neuroblastoma. mIBG can also be used therapeutically, labeled with 131-I, as a radiopharmaceutical agent, delivering targeted radiotherapy to tumoral sites. But published data of this strategy show heterogeneous results. One concern is that in most reports the infused activity is only based in bodyweight , which could lead to infra or over-treatment, depending on inter-patient variability in radiation absorption. Activity adjustment by whole-body dosimetry can be used to homogeneize the treatment. Also, mIBG avid tumors may lose avidness along the treatment. As mIBG is used both for treatment and response evaluation, this could result in undetected progressions in patients with apparent complete response. We present a retrospective single-center review of neuroblastoma patients who received therapeutic 131-I-mIBG, focusing on cases with dosimetry-adjusted activity. Dosimetry allowed for a more precise delivery of radiation, reducing 81.1% of deviation from absorption target of 4 Gray (Gy), from 23.4% (±0.936 Gy) to 4.4% (± 0.176 Gy). Patients who showed partial or complete response had better and longer survival. Relapse/progression in non-responders was an early event (within 3 months from treatment). We also present one case of progression with apparent complete response due to loss of mIBG avidness, detected in our series.

Human cytomegalovirus (HCMV) may cause severe or fatal disease among immunocompromised patients. The first line prophylaxis and systemic HCMV disease therapy is ganciclovir (GCV). The presence of GCV-resistant virus has been linked to fatal HCMV disease. The implementation of rapid and sensitive techniques for the early detection and monitoring of GCV-resistance may be helpful to support antiviral therapy management. A pyrosequencing assay for the detection and quantitation of the most frequent mutations conferring moderate- and high-grade GCV resistance was implemented. The pyrosequencing achieved an analytical sensitivity for adequate interpretation of ≥10(3)  copies/ml. The assay was validated with 18 whole blood samples taken over a 6-month period from an umbilical cord blood recipient infected persistently with HCMV and allowed the detection and monitoring of the M460I and A594V GCV-resistant mutations. The percentage of resistant quasispecies ranged from 7.9% to 55.2% for the M460I mutation and from 19.8% to 43% for the A594V mutation. Clearance of the M460I mutation occurred in parallel with a decrease in the HCMV viremia, while the A594V mutation persisted. The pyrosequencing method for detection of GCV is sensitive enough to be used directly on clinical samples for the early identification of resistance mutations and allows the quantitation of resistant and wild type virus quasispecies within hours. The quantitation of minor resistant variants is an important issue to understand their relationship with viral load modification, and potentially anticipate treatment adjustment.