Is Rapid Exome Sequencing Standard of Care in the Neonatal and Pediatric Intensive Care Units?

Current Practices for Genetic Testing in Neonatal Extracorporeal Membrane Oxygenation: Findings from a National survey

Introduction: Comprehensive genetic testing with whole-exome (WES) or whole-genome (WGS) sequencing facilitates diagnosis, can optimize treatment, and may improve outcomes in critically ill neonates, including those requiring extracorporeal membrane oxygenation (ECMO) for respiratory failure. Our objective was to describe practice variation and barriers to the utilization of comprehensive genetic testing for neonates on ECMO.Methods: We performed a cross-sectional survey of Level IV neonatal intensive care units in the United States across the Children's Hospitals Neonatal Consortium (CHNC).Results: Common indications for WES and WGS included concerning phenotype, severity of disease, unexpected postnatal clinical course, and inability to wean from ECMO support. Unexpected severity of disease on ECMO was the most common indication for rapid genetic testing. Cost of utilization was the primary barrier to testing. If rapid WES or WGS were readily available, 63% of centers would consider incorporating universal screening for neonates upon ECMO cannulation.Conclusion: Despite variation in the use of WES and WGS, universal testing may offer earlier diagnosis and influence the treatment course among neonates on ECMO. Cost is the primary barrier to utilization and most centers would consider incorporating universal screening on ECMO if readily available.

Select Ethical Aspects of Next-Generation Sequencing Tests for Newborn Screening and Diagnostic Evaluation of Critically Ill Newborns

In this review, we analyze medical and select ethical aspects of the increasing use of next-generation sequencing (NGS) based tests in newborn medicine. In the last five years, there have been several studies exploring the role of rapid exome sequencing (ES) and genome sequencing (GS) in critically ill newborns. While the advantages include a high diagnostic yield with potential changes in interventions, there have been ethical dilemmas surrounding consent, information about adult-onset diseases and resolution of variants of uncertain significance. Another active area of research includes a cohort of studies funded under Newborn Sequencing in Genomic Medicine and Public Health pertaining to the use of ES and GS in newborn screening (NBS). While these techniques may allow for screening for several genetic disorders that do not have a detectable biochemical marker, the high costs and long turnaround times of these tests are barriers in their utilization as public health screening tests. Discordant results between conventional NBS and ES-based NBS, as well as challenges with consent, are other potential pitfalls of this approach. Please see the Bush, Al-Hertani and Bodamer article in this Special Issue for the broader scope and further discussion.

What can go wrong in the non-coding genome and how to interpret whole genome sequencing data

Whole exome sequencing discovers causative mutations in less than 50 % of rare disease patients, suggesting the presence of additional mutations in the non-coding genome. So far, non-coding mutations have been identified in less than 0.2 % of individuals with genetic diseases listed in the ClinVar database and exhibit highly diverse molecular mechanisms. In contrast to our capability to sequence the whole genome, our ability to discover and functionally confirm such non-coding mutations is lagging behind severely. We discuss the problems and present examples of confirmed mutations in deep intronic sequences, non-coding triplet repeats, enhancers, and larger structural variants and highlight their proposed disease mechanisms. Finally, we discuss the type of data that would be required to establish non-coding mutation detection in routine diagnostics.

Genetic Testing for Neonatal Respiratory Disease

Genetic mechanisms are now recognized as rare causes of neonatal lung disease. Genes potentially responsible for neonatal lung disease include those encoding proteins important in surfactant function and metabolism, transcription factors important in lung development, proteins involved in ciliary assembly and function, and various other structural and immune regulation genes. The phenotypes of infants with genetic causes of neonatal lung disease may have some features that are difficult to distinguish clinically from more common, reversible causes of lung disease, and from each other. Multigene panels are now available that can allow for a specific diagnosis, providing important information for treatment and prognosis. This review discusses genes in which abnormalities are known to cause neonatal lung disease and their associated phenotypes, and advantages and limitations of genetic testing.