Evaluating the strength of evidence for genes implicated in peroxisomal disorders using the ClinGen clinical validity framework and providing updates to the peroxisomal disease nomenclature.

Peroxisomal disorders are heterogeneous in nature, with phenotypic overlap that is indistinguishable without molecular testing. Newborn screening and gene sequencing for a panel of genes implicated in peroxisomal diseases are critical tools for the early and accurate detection of these disorders. It is therefore essential to evaluate the clinical validity of the genes included in sequencing panels for peroxisomal disorders. The Peroxisomal Gene Curation Expert Panel (GCEP) assessed genes frequently included on clinical peroxisomal testing panels using the Clinical Genome Resource (ClinGen) gene-disease validity curation framework and classified gene-disease relationships as Definitive, Strong, Moderate, Limited, Disputed, Refuted, or No Known Disease Relationship. Subsequent to gene curation, the GCEP made recommendations to update the disease nomenclature and ontology in the Monarch Disease Ontology (Mondo) database. Thirty-six genes were assessed for the strength of evidence supporting their role in peroxisomal disease, leading to 36 gene-disease relationships, after two genes were removed for their lack of a role in peroxisomal disease and two genes were curated for two different disease entities each. Of these, 23 were classified as Definitive (64%), one as Strong (3%), eight as Moderate (23%), two as Limited (5%), and two as No known disease relationship (5%). No contradictory evidence was found to classify any relationships as Disputed or Refuted. The gene-disease relationship curations are publicly available on the ClinGen website (https://clinicalgenome.org/affiliation/40049/). The changes to peroxisomal disease nomenclature are displayed on the Mondo website (http://purl.obolibrary.org/obo/MONDO_0019053). The Peroxisomal GCEP-curated gene-disease relationships will inform clinical and laboratory diagnostics and enhance molecular testing and reporting. As new data will emerge, the gene-disease classifications asserted by the Peroxisomal GCEP will be re-evaluated periodically.

Effectiveness of Granulocyte Colony-Stimulating Factor in Hospitalized Infants with Neutropenia.

Objective The objective of this study was to determine the time to hematologic recovery and the incidence of secondary sepsis and mortality among neutropenic infants treated or not treated with granulocyte colony-stimulating factor (G-CSF). Study Design We identified all neutropenic infants discharged from 348 neonatal intensive care units from 1997 to 2012. Neutropenia was defined as an absolute neutrophil count ≤ 1,500/µL for ≥ 1 day during the first 120 days of life. Incidence of secondary sepsis and mortality and number of days required to reach an absolute neutrophil count > 1,500/µL for infants exposed to G-CSF were compared with those of unexposed infants. Results We identified 30,705 neutropenic infants, including 2,142 infants (7%) treated with G-CSF. Treated infants had a shorter adjusted time to hematologic recovery (hazard ratio: 1.36, 95% confidence interval [CI]: 1.30-1.44) and higher adjusted odds of secondary sepsis (odds ratio [OR]: 1.50, 95% CI: 1.20-1.87), death (OR: 1.33, 95% CI: 1.05-1.68), and the combined outcome of sepsis or death (OR: 1.41, 95% CI: 1.19-1.67) at day 14 compared with untreated infants. These differences persisted at day 28. Conclusion G-CSF treatment decreased the time to hematologic recovery but was associated with increased odds of secondary sepsis and mortality in neutropenic infants. G-CSF should not routinely be used for infants with neutropenia.