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Abstract. A well but cyanotic newborn was found to have a mutant gamm-globin chain, leading to a functionally abnormal fetal hemoglobin. A single amino acid substitution was found in a site consistent with known adult M hemoglobins. This patient showed no clinical evidence of cyanosis at 5 weeks of age as gamma-chain synthesis was replaced by beta-chain synthesis. A sibling born 20 months later was also cyanotic and the same mutant hemoglobin was found. [ABSTRACT FROM AUTHOR]

Objectives: To derive systematic-review informed, modified Delphi consensus regarding the influence of extracorporeal membrane oxygenation (ECMO) circuit components on anticoagulation practices for pediatric ECMO for the Pediatric ECMO Anticoagulation CollaborativE., Data Sources: A structured literature search was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021., Study Selection: Management of ECMO anticoagulation in the setting of different ECMO circuit components., Data Extraction: Two authors reviewed all citations independently, with a third independent reviewer resolving conflicts. Twenty-nine references were used for data extraction and informed recommendations, evidence-based consensus statements, and good practice statements. Evidence tables were constructed using a standardized data extraction form., Data Synthesis: Risk of bias was assessed using the Quality in Prognosis Studies tool. The evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation system. Forty-eight experts met over 2 years to develop evidence-based recommendations and, when evidence was lacking, expert-based consensus statements or good practice statements for the influence of ECMO circuit and components on anticoagulation management. A web-based modified Delphi process was used to build consensus via the Research And Development/University of California Appropriateness Method. Consensus was defined as greater than 80% agreement. One good practice statement, 2 weak recommendations, and 2 consensus statements are presented., Conclusions: The incorporation of new component technologies into clinical practice has outpaced clinical investigations of anticoagulation strategies for pediatric ECMO. Future investigations should leverage academic and industrial collaborations, translational platforms, and modern biostatistical methods to improve patient outcomes., Competing Interests: Dr. Himebauch receives support from the National Heart, Lung, and Blood Institute of the National Institutes of Health (NIH) under award number K23HL153759. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. Dr. Said acknowledges research support from the Children’s Discovery Institute Faculty Development Award at Washington University in St. Louis. Dr. Turner is used by the American Board of Pediatrics, and the content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the American Board of Pediatrics. Drs. Muszynski, and Alexander received support for article research from the NIH. Dr. Alexander’s institution received funding from the National Institute of Child Health and Human Development (1R13HD104432), Extracorporeal Life Support Organization (ELSO), and Novartis. Dr. Paden received funding from ELSO, he disclosed that he is past president and board member of ELSO, and he disclosed the off-label product use of extracorporeal membrane oxygenation. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.)

Extracorporeal Membrane Oxygenation (ECMO) is a technology that offers organ support for critically ill patients with respiratory and/or cardiac failure. Despite improvements in recent years in technology and the biocompatibility of circuits, patients on ECMO remain at high risk of hematologic complications, such as bleeding or thrombosis. Anticoagulation is required in most cases to limit the risk of clotting, but questions persist regarding the optimal anticoagulation strategy. More precisely, there is still debate around the best anticoagulation agent and monitoring tools as well as on the transfusion thresholds and appropriate corrective measures when faced with complications. This narrative review provides an overview of hemostasis on ECMO and the impact of circuit size and coating. The benefits and downsides of unfractionated heparin (UHF) and Direct Thrombin Inhibitors (DTIs) as anticoagulation agents are reviewed. Finally, commonly available coagulation tests (activated clotting time, activated partial thrombin time, anti-Xa, and viscoelastic tests) and their limitations are addressed. In conclusion, future research is needed to determine the best anticoagulation strategy for patients on ECMO., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Pituitary blastoma (PitB) has recently been identified as a rare and potentially lethal pediatric intracranial tumor. All cases that have been studied molecularly possess at least one DICER1 pathogenic variant. Here, we characterized nine pituitary samples, including three fresh frozen PitBs, three normal fetal pituitary glands and three normal postnatal pituitary glands using small-RNA-Seq, RNA-Seq, methylation profiling, whole genome sequencing and Nanostring® miRNA analyses; an extended series of 21 pituitary samples was used for validation purposes. These analyses demonstrated that DICER1 RNase IIIb hotspot mutations in PitBs induced improper processing of miRNA precursors, resulting in aberrant 5p-derived miRNA products and a skewed distribution of miRNAs favoring mature 3p over 5p miRNAs. This led to dysregulation of hundreds of 5p and 3p miRNAs and concomitant dysregulation of numerous mRNA targets. Gene expression analysis revealed PRAME as the most significantly upregulated gene (500-fold increase). PRAME is a member of the Retinoic Acid Receptor (RAR) signaling pathway and in PitBs, the RAR, WNT and NOTCH pathways are dysregulated. Cancer Hallmarks analysis showed that PI3K pathway is activated in the tumors. Whole genome sequencing demonstrated a quiet genome with very few somatic alterations. The comparison of methylation profiles to publicly available data from ~ 3000 other central nervous system tumors revealed that PitBs have a distinct methylation profile compared to all other tumors, including pituitary adenomas. In conclusion, this comprehensive characterization of DICER1-related PitB revealed key molecular underpinnings of PitB and identified pathways that could potentially be exploited in the treatment of this tumor.

DICER1 syndrome is a rare tumor predisposition syndrome with manifestations that predominantly affect children and young adults. The syndrome is typically caused by heterozygous germline loss-of-function DICER1 alterations accompanied on the other allele by somatic missense mutations occurring at one of a few mutation hotspots within the sequence encoding the RNase IIIb domain. DICER1 encodes a member of the microRNA biogenesis machinery. The syndrome spectrum is highly pleiotropic and features a unique constellation of benign and malignant neoplastic and dysplastic lesions. Pleuropulmonary blastoma (PPB), the most common primary lung cancer in children, is the hallmark tumor of the syndrome. Other manifestations include ovarian Sertoli-Leydig cell tumor, cystic nephroma arising in childhood, multinodular goiter, thyroid carcinoma, anaplastic sarcoma of the kidney, embryonal rhabdomyosarcoma, and nasal chondromesenchymal hamartoma, in addition to other rare entities. Several central nervous system (CNS) manifestations have also been defined, including metastases of PPB to the cerebrum, pituitary blastoma, pineoblastoma, ciliary body medulloepithelioma, and most recently primary DICER1-associated CNS sarcomas and ETMR-like infantile cerebellar embryonal tumor. Macrocephaly is a recently reported non-neoplastic, haploinsufficient phenotype. In this manuscript, we review the CNS manifestations of DICER1 syndrome.

DICER1 syndrome is a highly pleiotropic tumor predisposition syndrome that has been increasingly recognized in the last 10 years. Diseases in the syndrome result from mutations in both copies of the gene DICER1, a highly conserved gene that is critically implicated in micro-ribonucleic acid (miRNA) biogenesis and hence modulation of messenger RNAs. In general, susceptible individuals carry an inherited germline mutation that disables one copy of DICER1; within tumors, a very characteristic second mutation alters function of the other gene copy. About 20 hamartomatous, hyperplastic or neoplastic conditions comprise DICER1 syndrome. Most are not life-threatening, but some are aggressive malignancies. There are many unaffected carriers because penetrance is generally low; however, clinically occult thyroid nodules and lung cysts are frequent. Rare diseases of early childhood were the first recognized conditions in DICER1 syndrome, while other conditions affect adolescents and adults. The hallmarks of DICER1 syndrome are certain rare tumors including pleuropulmonary blastoma; cystic nephroma; ovarian Sertoli-Leydig cell tumor; sarcomas of the cervix, kidneys and cerebrum; pituitary blastoma; ciliary body medulloepithelioma; and nasal chondromesenchymal hamartoma. Radiologists are often the first practitioners to observe these diverse manifestations and play a primary role in recognizing DICER1 syndrome.

Germ-line DICER1 mutations predispose to a distinctive tumour predisposition syndrome, the DICER1 syndrome, which is associated with a spectrum of rare mainly childhood-onset tumours. In 2014, a case of well-differentiated fetal adenocarcinoma of the lung (WDFA) was reported in a 16-year-old germ-line DICER1 mutation carrier. Here we report our finding of a characteristic somatic DICER1 RNase IIIb c.5127T>A (p.Asp1709Glu) missense mutation within the WDFA, confirmed using laser capture microscopy. The child has a personal history consistent with the DICER1 syndrome: she developed a multinodular goitre at age 14 years and an ovarian Sertoli-Leydig cell tumour at age 16 years, each of which were found to harbour a somatic DICER1 RNase IIIb missense mutation. The identification of two DICER1 "hits" in the WDFA strongly suggests that WDFA is a rare, previously-unrecognised manifestation of DICER1 syndrome., (Copyright © 2015 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Background: Somatic mosaicism is being increasingly recognised as an important cause of non-Mendelian presentations of hereditary syndromes. A previous whole-exome sequencing study using DNA derived from peripheral blood identified mosaic mutations in DICER1 in two children with overgrowth and developmental delay as well as more typical phenotypes of germline DICER1 mutation. However, very-low-frequency mosaicism is difficult to detect, and thus, causal mutations can go unnoticed. Highly sensitive, cost-effective approaches are needed to molecularly diagnose these persons. We studied four children with multiple primary tumours known to be associated with the DICER1 syndrome, but in whom germline DICER1 mutations were not detected by conventional mutation detection techniques., Methods and Results: We observed the same missense mutation within the DICER1 RNase IIIb domain in multiple tumours from different sites in each patient, raising suspicion of somatic mosaicism. We implemented three different targeted-capture technologies, including the novel HaloPlex(HS) (Agilent Technologies), followed by deep sequencing, and confirmed that the identified mutations are mosaic in origin in three patients, detectable in 0.24-31% of sequencing reads in constitutional DNA. The mosaic origin of patient 4's mutation remains to be unequivocally established. We also discovered likely pathogenic second somatic mutations or loss of heterozygosity (LOH) in tumours from all four patients., Conclusions: Mosaic DICER1 mutations are an important cause of the DICER1 syndrome in patients with severe phenotypes and often appear to be accompanied by second somatic truncating mutations or LOH in the associated tumours. Furthermore, the molecular barcode-containing HaloPlex(HS) provides the sensitivity required for detection of such low-level mosaic mutations and could have general applicability., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objective: The purpose of this study was to compare the risks of radiation in screening strategies using chest radiographs and CT to detect a rare cancer in a genetically predisposed population against the risks of undetected disease., Materials and Methods: A decision analytic model of diagnostic imaging screening strategies was built to predict outcomes and cumulative radiation doses for children with DICER1 mutations screened for pleuropulmonary blastoma. Screening strategies compared were chest radiographs followed by chest CT for a positive radiographic result and CT alone. Screening frequencies ranged from once in 3 years to once every 3 months. BEIR VII (model VII proposed by the Committee on the Biological Effects of Ionizing Radiation) risk tables were used to predict excess cancer mortality for each strategy, and the corresponding loss of life expectancy was calculated using Surveillance Epidemiologic and End Results (SEER) statistics. Loss of life expectancy owing to undetected progressive pleuropulmonary blastoma was estimated on the basis of data from the International Pleuropulmonary Blastoma Registry. Sensitivity analysis was performed for all model parameters., Results: Loss of life expectancy owing to undetected disease in an unscreened population exceeded that owing to radiation-induced cancer for all screening scenarios investigated. Increases in imaging frequency decreased loss of life expectancy for the combined (chest radiographs and CT) screening strategy but increased that for the CT-only strategy. This was because loss of life expectancy for combined screening is dominated by undetected disease, whereas loss of life expectancy for CT screening is dominated by radiation-induced cancers., Conclusion: Even for a rare disease such as pleuropulmonary blastoma, radiographic screening of infants and young children with cancer-predisposing mutations may result in improved life expectancy compared with the unscreened population. The benefit of screening will be greater for diseases with a higher screening yield.

Germ-line RB-1 mutations predispose to pineoblastoma (PinB), but other predisposing genetic factors are not well established. We recently identified a germ-line DICER1 mutation in a child with a PinB. This was accompanied by loss of heterozygosity (LOH) of the wild-type allele within the tumour. We set out to establish the prevalence of DICER1 mutations in an opportunistically ascertained series of PinBs. Twenty-one PinB cases were studied: Eighteen cases had not undergone previous testing for DICER1 mutations; three patients were known carriers of germ-line DICER1 mutations. The eighteen PinBs were sequenced by Sanger and/or Fluidigm-based next-generation sequencing to identify DICER1 mutations in blood gDNA and/or tumour gDNA. Testing for somatic DICER1 mutations was also conducted on one case with a known germ-line DICER1 mutation. From the eighteen PinBs, we identified four deleterious DICER1 mutations, three of which were germ line in origin, and one for which a germ line versus somatic origin could not be determined; in all four, the second allele was also inactivated leading to complete loss of DICER1 protein. No somatic DICER1 RNase IIIb mutations were identified. One PinB arising in a germ-line DICER1 mutation carrier was found to have LOH. This study suggests that germ-line DICER1 mutations make a clinically significant contribution to PinB, establishing DICER1 as an important susceptibility gene for PinB and demonstrates PinB to be a manifestation of a germ-line DICER1 mutation. The means by which the second allele is inactivated may differ from other DICER1-related tumours.

Individuals harboring germ-line DICER1 mutations are predisposed to a rare cancer syndrome, the DICER1 Syndrome or pleuropulmonary blastoma-familial tumor and dysplasia syndrome [online Mendelian inheritance in man (OMIM) #601200]. In addition, specific somatic mutations in the DICER1 RNase III catalytic domain have been identified in several DICER1-associated tumor types. Pituitary blastoma (PitB) was identified as a distinct entity in 2008, and is a very rare, potentially lethal early childhood tumor of the pituitary gland. Since the discovery by our team of an inherited mutation in DICER1 in a child with PitB in 2011, we have identified 12 additional PitB cases. We aimed to determine the contribution of germ-line and somatic DICER1 mutations to PitB. We hypothesized that PitB is a pathognomonic feature of a germ-line DICER1 mutation and that each PitB will harbor a second somatic mutation in DICER1. Lymphocyte or saliva DNA samples ascertained from ten infants with PitB were screened and nine were found to harbor a heterozygous germ-line DICER1 mutation. We identified additional DICER1 mutations in nine of ten tested PitB tumor samples, eight of which were confirmed to be somatic in origin. Seven of these mutations occurred within the RNase IIIb catalytic domain, a domain essential to the generation of 5p miRNAs from the 5' arm of miRNA-precursors. Germ-line DICER1 mutations are a major contributor to PitB. Second somatic DICER1 "hits" occurring within the RNase IIIb domain also appear to be critical in PitB pathogenesis.

The discovery of each new cancer susceptibility gene answers one set of questions but poses many more. In this article, we outline a recent example: a new cancer syndrome caused by germline mutations in DICER1, responsible for microRNA processing. In particular, we discuss the endocrine manifestations of mutations in this crucial gene., (Copyright © 2012. Published by Elsevier Ltd.)

Objective: Pleuropulmonary blastoma (PPB) is a childhood cancer arising from pleuropulmonary mesenchyme. This neoplasm is a sentinel disease in a familial tumor syndrome recently found to be associated with germline mutations in DICER1. Observations of ovarian sex cord-stromal tumors (OSCST) in PPB kindreds led to further study. We sought to characterize ovarian tumors seen in probands and families with PPB and PPB-related conditions and define germline DICER1 status., Methods: Patient and family records of pathology-reviewed PPB cases enrolled in the International PPB Registry (IPPBR) were searched for ovarian tumors. Ovarian tumor pathology specimens were obtained and centrally reviewed. Germline DNA from patients with ovarian tumors was tested for DICER1 mutations. Three additional OSCST patients registered in the IPPBR were also tested for mutations in DICER1., Results: Among 296 kindreds including 325 children with PPB, we observed three children with both PPB and Sertoli-Leydig cell tumors (SLCT)/Sertoli cell tumors. Among family members of PPB patients, we identified six OSCST (three SLCT, one Sertoli cell tumor, one juvenile granulosa cell tumor, one gynandroblastoma). Age at ovarian tumor diagnosis was youngest in PPB probands and younger in family members than in OSCST in general. Germline DICER1 mutations were identified in four of six patients with OSCST from PPB kindreds and in two of three children with OSCST and no personal or family history of PPB., Conclusions: Primary ovarian neoplasms, particularly OSCST, are a manifestation of the familial PPB syndrome and may be the initial clinical presentation of DICER1 mutations within a family., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Pleuropulmonary blastoma (PPB) is a rare pediatric lung tumor that is often part of an inherited cancer syndrome. PPBs consist of mesenchymal cells that are susceptible to malignant transformation and cysts lined by epithelial cells. In a subset of patients, overgrowth of the cysts by mesenchymal cells leads to sarcoma formation. Here, we show that 11 multiplex PPB families harbor heterozygous germline mutations in DICER1, a gene encoding an endoribonuclease critical to the generation of small noncoding regulatory RNAs. Expression of DICER1 protein was undetectable in the epithelial component of PPB tumors but was retained in the malignant mesenchyme (sarcoma). We hypothesize that loss of DICER1 in the epithelium of the developing lung alters the regulation of diffusible factors that promote mesenchymal proliferation.