Spliceosome malfunction causes neurodevelopmental disorders with overlapping features.

Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50-deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function.

A Survey of PICU Clinician Practices and Perceptions regarding Respiratory Cultures in the Evaluation of Ventilator-Associated Infections in the BrighT STAR Collaborative.

OBJECTIVES: To characterize respiratory culture practices for mechanically ventilated patients, and to identify drivers of culture use and potential barriers to changing practices across PICUs. DESIGN: Cross-sectional survey conducted May 2021-January 2022. SETTING: Sixteen academic pediatric hospitals across the United States participating in the BrighT STAR Collaborative. SUBJECTS: Pediatric critical care medicine physicians, advanced practice providers, respiratory therapists, and nurses. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We summarized the proportion of positive responses for each question within a hospital and calculated the median proportion and IQR across hospitals. We correlated responses with culture rates and compared responses by role. Sixteen invited institutions participated (100%). Five hundred sixty-eight of 1,301 (44%) e-mailed individuals completed the survey (median hospital response rate 60%). Saline lavage was common, but no PICUs had a standardized approach. There was the highest variability in perceived likelihood (median, IQR) to obtain cultures for isolated fever (49%, 38-61%), isolated laboratory changes (49%, 38-57%), fever and laboratory changes without respiratory symptoms (68%, 54-79%), isolated change in secretion characteristics (67%, 54-78%), and isolated increased secretions (55%, 40-65%). Respiratory cultures were likely to be obtained as a "pan culture" (75%, 70-86%). There was a significant correlation between higher culture rates and likelihood to obtain cultures for isolated fever, persistent fever, isolated hypotension, fever, and laboratory changes without respiratory symptoms, and "pan cultures." Respondents across hospitals would find clinical decision support (CDS) helpful (79%) and thought that CDS would help align ICU and/or consulting teams (82%). Anticipated barriers to change included reluctance to change (70%), opinion of consultants (64%), and concern for missing a diagnosis of ventilator-associated infections (62%). CONCLUSIONS: Respiratory culture collection and ordering practices were inconsistent, revealing opportunities for diagnostic stewardship. CDS would be generally well received; however, anticipated conceptual and psychologic barriers to change must be considered.

Microbiome dysbiosis: a modifiable state and target to prevent Staphylococcus aureus infections and other diseases in neonates.

Bacterial infections present a significant threat to neonates. Increasingly, studies demonstrate associations between human diseases and the microbiota, the communities of microorganisms on or in the body. A "healthy" microbiota with a great diversity and balance of microorganisms can resist harmful pathogens and protect against infections, whereas a microbiota suffering from dysbiosis, can predispose to pathogen colonization and subsequent infection. For decades, strategies such as bacterial interference, decolonization, prebiotics, and probiotics have been tested to reduce Staphylococcus aureus disease and other infections in neonates. More recently, microbiota transplant has emerged as a strategy to broadly correct dysbiosis, promote colonization resistance, and prevent infections. This paper discusses the benefits of a healthy neonate's microbiota, exposures that alter the microbiota, associations of dysbiosis and neonatal disease, strategies to prevent dysbiosis, such as microbiota transplantation, and presents a framework of microbiome manipulation to reduce Staphylococcus aureus (S. aureus) and other infections in neonates.