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Purpose: To characterize the diagnostic and clinical outcomes of a cohort of critically ill infants and children with suspected mitochondrial disorders (MD) undergoing ultra-rapid genomic testing as part of a national program., Methods: Ultra-rapid genomic sequencing was performed in 454 families (genome sequencing: n=290, exome sequencing +/- mitochondrial DNA sequencing: n=164). In 91 individuals, MD was considered, prompting analysis using an MD virtual gene panel. These individuals were reviewed retrospectively and scored according to modified Nijmegen Mitochondrial Disease Criteria., Results: A diagnosis was achieved in 47% (43/91) of individuals, 40% (17/43) of whom had an MD. Seven additional individuals in whom an MD was not suspected were diagnosed with an MD following broader analysis. Gene-agnostic analysis led to the discovery of two novel disease genes, with pathogenicity validated through targeted functional studies (CRLS1 and MRPL39). Functional studies enabled diagnosis in another four individuals. Of the 24 individuals ultimately diagnosed with an MD, 79% had a change in management, which included 53% whose care was redirected to palliation., Conclusion: Ultra-rapid genetic diagnosis of MD in acutely unwell infants and children is critical for guiding decisions about the need for additional investigations and clinical management., (Copyright © 2024. Published by Elsevier Inc.)

Purpose: To explore parental experiences of ultrarapid genomic testing for their critically unwell infants and children., Methods: Parents of critically unwell children who participated in a national ultrarapid genomic diagnosis program were surveyed >12 weeks after genomic results return. Surveys consisted of custom questions and validated scales, including the Decision Regret Scale and Genomics Outcome Scale., Results: With 96 survey invitations sent, the response rate was 57% (n = 55). Most parents reported receiving enough information during pretest (n = 50, 94%) and post-test (n = 44, 83%) counseling. Perceptions varied regarding benefits of testing, however most parents reported no or mild decision regret (n = 45, 82%). The majority of parents (31/52, 60%) were extremely concerned about the condition recurring in future children, regardless of actual or perceived recurrence risk. Parents whose child received a diagnostic result reported higher empowerment., Conclusion: This study provides valuable insight into parental experiences of ultrarapid genomic testing in critically unwell children, including decision regret, empowerment, and post-test reproductive planning, to inform design and delivery of rapid diagnosis programs. The findings suggest considerations for pre- and post-test counseling that may influence parental experiences during the testing process and beyond, such as the importance of realistically conveying the likelihood for clinical and/or personal utility.

Prominent skin involvement is a defining characteristic of autoinflammatory disorders caused by abnormal IL-1 signaling. However, the pathways and cell types that drive cutaneous autoinflammatory features remain poorly understood. We sought to address this issue by investigating the pathogenesis of pustular psoriasis, a model of autoinflammatory disorders with predominant cutaneous manifestations. We specifically characterized the impact of mutations affecting AP1S3, a disease gene previously identified by our group and validated here in a newly ascertained patient resource. We first showed that AP1S3 expression is distinctively elevated in keratinocytes. Because AP1S3 encodes a protein implicated in autophagosome formation, we next investigated the effects of gene silencing on this pathway. We found that AP1S3 knockout disrupts keratinocyte autophagy, causing abnormal accumulation of p62, an adaptor protein mediating NF-κB activation. We showed that as a consequence, AP1S3-deficient cells up-regulate IL-1 signaling and overexpress IL-36α, a cytokine that is emerging as an important mediator of skin inflammation. These abnormal immune profiles were recapitulated by pharmacological inhibition of autophagy and verified in patient keratinocytes, where they were reversed by IL-36 blockade. These findings show that keratinocytes play a key role in skin autoinflammation and identify autophagy modulation of IL-36 signaling as a therapeutic target., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)