Diagnosis, treatment, and surveillance of Diamond-Blackfan anaemia syndrome: international consensus statement.

Diamond-Blackfan anaemia (DBA), first described over 80 years ago, is a congenital disorder of erythropoiesis with a predilection for birth defects and cancer. Despite scientific advances, this chronic, debilitating, and life-limiting disorder continues to cause a substantial physical, psychological, and financial toll on patients and their families. The highly complex medical needs of affected patients require specialised expertise and multidisciplinary care. However, gaps remain in effectively bridging scientific discoveries to clinical practice and disseminating the latest knowledge and best practices to providers. Following the publication of the first international consensus in 2008, advances in our understanding of the genetics, natural history, and clinical management of DBA have strongly supported the need for new consensus recommendations. In 2014 in Freiburg, Germany, a panel of 53 experts including clinicians, diagnosticians, and researchers from 27 countries convened. With support from patient advocates, the panel met repeatedly over subsequent years, engaging in ongoing discussions. These meetings led to the development of new consensus recommendations in 2024, replacing the previous guidelines. To account for the diverse phenotypes including presentation without anaemia, the panel agreed to adopt the term DBA syndrome. We propose new simplified diagnostic criteria, describe the genetics of DBA syndrome and its phenocopies, and introduce major changes in therapeutic standards. These changes include lowering the prednisone maintenance dose to maximum 0·3 mg/kg per day, raising the pre-transfusion haemoglobin to 9-10 g/dL independent of age, recommending early aggressive chelation, broadening indications for haematopoietic stem-cell transplantation, and recommending systematic clinical surveillance including early colorectal cancer screening. In summary, the current practice guidelines standardise the diagnostics, treatment, and long-term surveillance of patients with DBA syndrome of all ages worldwide.

Expression of DNA Repair Genes in Ewing Sarcoma.

Background/Aim: Ewing sarcoma is an aggressive mesenchymal malignancy commonly affecting children and young adolescents. The molecular basis of this neoplasia is well reported with the formation of the EWSR1/FLI1 fusion gene being the most common genetic finding. However, this fusion gene has not been targeted therapeutically nor is being used as a prognostic marker. Its relevance regarding the molecular steps leading to Ewing sarcoma genesis are yet to be defined. The generation of the oncogenic EWSR1/FLI1 fusion gene, can be attributed to the simultaneous introduction of two DNA double-strand breaks (DSBs). The scope of this study is to detect any association between DNA repair deficiency and the clinicopathological aspects of Ewing's sarcoma disease. Patients and Methods: We have conducted an expression analysis of 35 patients diagnosed with Ewing sarcoma concerning the genes involved in non-homologous end joining (NHEJ) and homologous recombination (HR) repair pathways. We have analyzed the expression levels of 6 genes involved in NHEJ (XRCC4, XRCC5, XRCC6, POLλ, POLµ) and 9 genes involved in HR (RAD51, RAD52, RAD54, BRCA1, BRCA2, FANCC, FANCD, DNTM1, BRIT1) using real time PCR. Age, sex, location of primary tumor, tumor size, KI67, mitotic count, invasion of adjacent tissues and treatment were the clinicopathological parameters included in the statistical analysis. Results: Our results show that both these DNA repair pathways are deregulated in Ewing sarcoma. In addition, low expression of the xrcc4 gene has been associated with better overall survival probability (p=0.032). Conclusion: Our results, even though retrospective and in a small number of patients, highlight the importance of DSBs repair and propose a potential therapeutic target for this type of sarcoma.

Iron chelation therapy for children with transfusion-dependent ß-thalassemia: How young is too young?

In this review, we provide a summary of evidence on iron overload in young children with transfusion-dependent ß-thalassemia (TDT) and explore the ideal timing for intervention. Key data from clinical trials and observational studies of the three available iron chelators deferoxamine, deferiprone, and deferasirox are also evaluated for inclusion of subsets of young children, especially those less than 6 years of age. Evidence on the efficacy and safety of iron chelation therapy for children ≥2 years of age with transfusional iron overload is widely available. New data exploring the risks and benefits of early-start iron chelation in younger patients with minimal iron overload are also emerging.

Gliomatosis cerebri in children: A poor prognostic phenotype of diffuse gliomas with a distinct molecular profile.

BACKGROUND: The term Gliomatosis cerebri (GC), a radiology-defined highly infiltrating diffuse glioma, has been abandoned since molecular GC-associated features have not been established yet. METHODS: We conducted a multinational retrospective study of 104 children and adolescents with GC providing comprehensive clinical and (epi-)genetic characterization. RESULTS: Median overall survival (OS) was 15.5 months (interquartile range, 10.9-27.7) with a 2-years survival rate of 28%. Histopathological grading correlated significantly with median OS: CNS WHO grade II: 47.8 months (25.2-55.7); grade III: 15.9 months (11.4-26.3); grade IV: 10.4 months (8.8-14.4). By DNA methylation profiling (n=49), most tumors were classified as pediatric-type diffuse high-grade glioma (pedHGG), H3-/IDH-wildtype (n=31/49, 63.3%) with enriched subclasses pedHGG_RTK2 (n=19), pedHGG_A/B (n=6), and pedHGG_MYCN (n=5), but only one pedHGG_RTK1 case. Within the pedHGG, H3-/IDH-wildtype subgroup, recurrent alterations in EGFR (n=10) and BCOR (n=9) were identified. Additionally, we observed structural aberrations in chromosome 6 in 16/49 tumors (32.7%) across tumor types. In the pedHGG, H3-/IDH-wildtype subgroup TP53 alterations had a significant negative effect on OS. CONCLUSION: Contrary to previous studies, our representative pediatric GC study provides evidence that GC has a strong predilection to arise on the background of specific molecular features (especially pedHGG_RTK2, pedHGG_A/B, EGFR and BCOR mutations, chromosome 6 rearrangements).

Venetoclax Combination Treatment of Acute Myeloid Leukemia in Adolescents and Young Adult Patients.

Over the past two decades, the prognosis in adolescents and young adults (AYAs) diagnosed with acute myeloid leukemia (AML) has significantly improved. The standard intensive cytotoxic treatment approach for AYAs with AML, consisting of induction chemotherapy with anthracycline/cytarabine combination followed by consolidation chemotherapy or stem cell transplantation, has lately been shifting toward novel targeted therapies, mostly in the fields of clinical trials. One of the most recent advances in treating AML is the combination of the B-cell lymphoma 2 (Bcl-2) inhibitor venetoclax with hypomethylating agents, which has been studied in elderly populations and was approved by the Food and Drug Administration (FDA) for patients over 75 years of age or patients excluded from intensive chemotherapy induction schemas due to comorbidities. Regarding the AYA population, venetoclax combination therapy could be a therapeutic option for patients with refractory/relapsed (R/R) AML, although data from real-world studies are currently limited. Venetoclax is frequently used by AYAs diagnosed with advanced hematologic malignancies, mainly acute lymphoblastic leukemia and myelodysplastic syndromes, as a salvage therapeutic option with considerable efficacy and safety. Herein, we aim to summarize the evidence obtained from clinical trials and observational studies on venetoclax use in AYAs with AML. Based on the available evidence, venetoclax is a safe and effective therapeutic option for R/R AML AYA patients. However, further research in larger cohorts is needed to confirm these data, establishing the benefits of a venetoclax-based regimen for this special population.

Exagamglogene Autotemcel for Transfusion-Dependent ß-Thalassemia.

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a nonviral cell therapy designed to reactivate fetal hemoglobin synthesis through ex vivo clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of the erythroid-specific enhancer region of BCL11A in autologous CD34+ hematopoietic stem and progenitor cells (HSPCs). METHODS: We conducted an open-label, single-group, phase 3 study of exa-cel in patients 12 to 35 years of age with transfusion-dependent ß-thalassemia and a ß0/ß0, ß0/ß0-like, or non-ß0/ß0-like genotype. CD34+ HSPCs were edited by means of CRISPR-Cas9 with a guide mRNA. Before the exa-cel infusion, patients underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end point was transfusion independence, defined as a weighted average hemoglobin level of 9 g per deciliter or higher without red-cell transfusion for at least 12 consecutive months. Total and fetal hemoglobin concentrations and safety were also assessed. RESULTS: A total of 52 patients with transfusion-dependent ß-thalassemia received exa-cel and were included in this prespecified interim analysis; the median follow-up was 20.4 months (range, 2.1 to 48.1). Neutrophils and platelets engrafted in each patient. Among the 35 patients with sufficient follow-up data for evaluation, transfusion independence occurred in 32 (91%; 95% confidence interval, 77 to 98; P<0.001 against the null hypothesis of a 50% response). During transfusion independence, the mean total hemoglobin level was 13.1 g per deciliter and the mean fetal hemoglobin level was 11.9 g per deciliter, and fetal hemoglobin had a pancellular distribution (≥94% of red cells). The safety profile of exa-cel was generally consistent with that of myeloablative busulfan conditioning and autologous HSPC transplantation. No deaths or cancers occurred. CONCLUSIONS: Treatment with exa-cel, preceded by myeloablation, resulted in transfusion independence in 91% of patients with transfusion-dependent ß-thalassemia. (Supported by Vertex Pharmaceuticals and CRISPR Therapeutics; CLIMB THAL-111 ClinicalTrials.gov number, NCT03655678.).

Open versus Transcutaneous (Ultrasound-Guided and Based on Anatomic Landmarks) Tunneled Venous Access to the Right Internal Jugular Vein in Children: A Prospective Single-Center Study.

BACKGROUND: The purpose of this study was to compare the immediate and long-term complications that are associated with the utilized techniques for the insertion of indwelling central venous catheters, that is the open surgical technique, the ultrasound-guided technique, and the transcutaneous technique based on external anatomical landmarks in the right internal jugular vein, to a pediatric population. METHODS: This was a prospective randomized trial based on a pediatric patient population under 16 years of age of a tertiary pediatric-oncological hospital. The procedure was performed by a medical team with varying experience regarding the percutaneous and open insertion methods. We studied the outcome of our procedure, based on the immediate and delayed complication rate, as well as the needed time in order to complete the procedure and mean duration of line use. RESULTS: The patients that were inserted in our protocol were divided into three subgroups based on the selected technique for the insertion of the central venous catheter. A total number of 88 insertions (25.4%) (out of 346) were based on the technique that was using external anatomical landmarks, 121 insertions were based on the ultrasound-guided transcutaneous technique (34.9%), whereas in 137 cases (39.5%) the open surgical technique was preferred. All cases that were related to catheter re-insertion were excluded from our study. We performed a statistical analysis regarding the catheter dwell time between the three subgroups of patients and no significant difference was recorded. Moreover, the development of thrombosis was investigated, and we noted that a higher percentage of this complication was related to the transcutaneous external landmark and open surgical technique. Also, the incidence of infection was taken into consideration, which manifested an increased incidence when the transcutaneous technique based on external landmarks was used. CONCLUSIONS: Ultrasound-guided percutaneous insertion was considered to be a safe and effective technique for the insertion of central venous catheters. Our study also demonstrated a decrease in operating times when performed by operators with increasing expertise, increased preservation of the diameter of the venous lumen, and no increase in complication rates when the ultrasound-guided technique was selected.

The Diverse Genomic Landscape of Diamond-Blackfan Anemia: Two Novel Variants and a Mini-Review.

Diamond-Blackfan anemia (DBA) is a ribosomopathy characterized by bone marrow erythroid hypoplasia, which typically presents with severe anemia within the first months of life. DBA is typically attributed to a heterozygous mutation in a ribosomal protein (RP) gene along with a defect in the ribosomal RNA (rRNA) maturation or levels. Besides classic DBA, DBA-like disease has been described with variations in 16 genes (primarily in GATA1, followed by ADA2 alias CECR1, HEATR3, and TSR2). To date, more than a thousand variants have been reported in RP genes. Splice variants represent 6% of identifiable genetic defects in DBA, while their prevalence is 14.3% when focusing on pathogenic and likely pathogenic (P/LP) variants, thus highlighting the impact of such alterations in RP translation and, subsequently, in ribosome levels. We hereby present two cases with novel pathogenic splice variants in RPS17 and RPS26. Associations of DBA-related variants with specific phenotypic features and malignancies and the molecular consequences of pathogenic variations for each DBA-related gene are discussed. The determinants of the spontaneous remission, cancer development, variable expression of the same variants between families, and selectivity of RP defects towards the erythroid lineage remain to be elucidated.

New-onset aplastic anemia after SARS-CoV-2 vaccination.

Aplastic anemia (AA) is a rare autoimmune disease. Drugs, viruses, and radiation are among the most common etiologic factors, and most cases have immune pathophysiology. SARS-CoV-2 vaccines have been linked with rare side effects, including cases of acquired aplastic anemia. Here we review all the reported cases of new-onset AA after SARS-CoV-2 vaccination, and discuss their clinical characteristics and management. 18 patients in these case reports had a median age of 58 years. The time from vaccination to onset of aplastic anemia ranged from 1 day to 7 months, with a median of 2.5 weeks. Seventeen patients were diagnosed with severe or very severe aplastic anemia post-vaccination and all patients received standard treatments for acquired aplastic anemia. Seventeen patients achieved a complete or partial response and only 1 patient died. Aplastic anemia can be considered a very rare SARS-CoV-2 vaccine-related adverse event, although a causative relationship has not been proven. Reporting cases of such uncommon post-vaccination events could help clinicians to consider aplastic anemia when pancytopenia is observed after vaccination. The benefits of SARS-Cov-2 vaccination are established, and reports of rare events serve only to increase awareness in daily clinical practice.

Real-world complication burden and disease management paradigms in transfusion-related ß-thalassaemia in Greece: Results from ULYSSES, an epidemiological, multicentre, retrospective cross-sectional study.

Patients with transfusion-dependent beta (ß)-thalassaemia experience a broad range of complications. ULYSSES, an epidemiological, multicentre, retrospective cross-sectional study, aimed to assess the prevalence and severity of treatment and disease complications, capture disease management and identify predictors of complications in patients with transfusion-dependent ß-thalassaemia, treated in routine settings in Greece. Eligible patients were adults diagnosed with ß-thalassaemia ≥12 months before enrolment and having received ≥6 red blood cell (RBC) units (excluding elective surgery) with no transfusion-free period ≥35 days in the 24 weeks before enrolment. Primary data were collected at a single visit and through chart review. Between Oct 21, 2019, and Jun 15, 2020, 201 eligible patients [median (interquartile range, IQR) age 45.7 (40.2-50.5) years; 75.6% > 40 years old; 64.2% female] were enrolled, a mean (standard deviation) of 42.9 (7.8) years after diagnosis. Median (IQR) age at diagnosis and RBC transfusion initiation were 0.8 (0.4-2.8) and 1.3 (1.0-5.0) years, respectively. From diagnosis to enrolment, patients had developed a median of six (range: 1-55) complications; 19.6% were grade ≥3. The most represented complications were endocrine/metabolic/nutrition disorders (91.5%), surgical/medical procedures (67.7%) and blood/lymphatic system disorders (64.7%). Real-world data generated by ULYSSES underscore the substantial complication burden of transfusion-dependent ß-thalassaemia patients, routinely managed in Greece.

A Novel Variant in the TP53 Gene Causing Li-Fraumeni Syndrome.

Li-Fraumeni syndrome (LFS) is an autosomal dominant hereditary cancer syndrome associated with germline pathogenic variants in the tumor protein p53 (TP53) gene and elevated risk of a broad range of early-onset malignancies. Patients with LFS are at risk of a second and third primary tumor. A 15-month-old girl consulted for clitoromegaly and pubic hair. Adrenal ultrasound detected a large left adrenal tumor. Left total adrenalectomy confirmed adrenocortical carcinoma. Family history revealed multiple highly malignant neoplasms at an early age across five generations, and a genetic dominant trait seemed probable. Whole-genome sequencing was performed. Multiple members of the family were found positive for a novel likely pathogenic variant (c. 892delGinsTTT, p. Glu298PhefsX48, NM_000546.6) in the TP53 gene, causing the loss of normal protein function through non-sense-mediated mRNA decay. According to the PSV1 supporting criteria and the Auto PVS1 online tool this frameshift variant: hg19/17-7577045-TC-TAAA:NM_000546.6 has a very strong, definitive clinical validity for LFS with autosomal dominant inheritance. Proper guidance resulted in timely diagnosis of a second tumor (primary osteosarcoma) in the index case and in the early detection of breast and cervical cancer in her young mother. Patients with cancer predisposition syndromes like LFS require close multidisciplinary cancer surveillance and appropriate referral to expert centers.

Sickle cell disease landscape and challenges in the EU: the ERN-EuroBloodNet perspective.

Sickle cell disease is a hereditary multiorgan disease that is considered rare in the EU. In 2017, the Rare Diseases Plan was implemented within the EU and 24 European Reference Networks (ERNs) were created, including the ERN on Rare Haematological Diseases (ERN-EuroBloodNet), dedicated to rare haematological diseases. This EU initiative has made it possible to accentuate existing collaborations and create new ones. The project also made it possible to list all the needs of people with rare haematological diseases not yet covered health-care providers in the EU to allow optimised care of individuals with rare pathologies, including sickle cell disease. This Viewpoint is the result of joint work within 12 EU member states (ie, Belgium, Cyprus, Denmark, France, Germany, Greece, Ireland, Italy, Portugal, Spain, Sweden, and The Netherlands), all members of the ERN-EuroBloodNet. We describe the role of the ERN-EuroBloodNet to improve the overall approach to and the management of individuals with sickle cell disease in the EU through specific on the pooling of expertise, knowledge, and best practices; the development of training and education programmes; the strategy for systematic gathering and standardisation of clinical data; and its reuse in clinical research. Epidemiology and research strategies from ongoing implementation of the Rare Anaemia Disorders European Epidemiological Platform is depicted.

Characteristics of Café-au-lait Macules and their Association with the Neurofibromatosis type I Genotype in a Cohort of Greek Children.

Cafe-au-lait macules are the most distinctive clinical finding in neurofibromatosis type I. The aim of this prospective study of Greek children diagnosed with neurofibromatosis type I was to describe the dermatological phenotype and to analyse the characteristics of cafe-au-lait macules and their association with genotype. Pigment intensity and melatonin content of cafe-au-lait macules were measured with a narrowband spectrophotometer. A total of 63 children aged 6 months to 16 years old were studied. Mean melanin content varied, both among patients, and within each patient (p < 0.001). Females had a higher number of cafe-au-lait macules than did males (p = 0.025), and the melanin content of cafe-au-lait macules was lower in females than males (p < 0.001). Patients with protein-truncating variants in the neurofibromatosis type I gene had higher melanin content of cafe-au-lait macules than other types of genetic variants t (55) = 2.196, p = 0.032. Plexiform neurofibromas were also detected in the majority of patients with protein- truncating variants, while juvenile xanthogranulomas were detected equally in patients with protein-truncating and non-protein-truncating variants. In conclusion, cafe-au-lait macules with high melatonin content are associated with patients carrying non-protein-truncating variants. Therefore, measurement of cafe-au-lait macule pigment intensity might provide useful information for initial assessment of patients with neurofibromatosis type I and the severity of their future phenotype.

Evidence that platelets from transfusion-dependent ß-thalassemia patients induce T cell activation.

A hypercoagulable state leading to increased risk for thrombotic events represents one of the most common complications observed in transfusion-dependent ß-thalassemia (TDT) patients. TDT patients have increased frequencies of circulating activated platelets. However, there is no information so far if platelets from TDT patients can activate T cells. In the present study we showed that T cells treated with platelets from TDT patients showed significant increased surface expression of CD69 compared to the T cells treated with platelets from healthy individuals. Patients with splenectomy showed increased T cell activation compared to patients with intact spleen. No T cell activation was observed following incubation with plasma alone, nor with platelets from healthy subjects. The percentages of regulatory T cells (Tregs) were also examined. TDT patients showed statistically significant increased percentages of Tregs compared to healthy controls. Additionally, we observed a positive statistically significant correlation between the percentages of Tregs and the platelet-induced activated T cells in patients who were not treated with aspirin. TDT patients showed increased levels of sP-selectin, suPAR and GDF-15, molecules implicated in platelet activation. We show that platelets from TDT patients can activate T cells in vitro. This activation correlates with markers of platelet activation and increased numbers of Tregs, perhaps in an effort to eliminate immune dysregulation, conceivably secondary to platelet activation.

Telomere biology: from disorders to hematological diseases.

Variations in the length of telomeres and pathogenic variants involved in telomere length maintenance have been correlated with several human diseases. Recent breakthroughs in telomere biology knowledge have contributed to the identification of illnesses named "telomeropathies" and revealed an association between telomere length and disease outcome. This review emphasizes the biology and physiology aspects of telomeres and describes prototype diseases in which telomeres are implicated in their pathophysiology. We also provide information on the role of telomeres in hematological diseases ranging from bone marrow failure syndromes to acute and chronic leukemias.

Outcome of Children and Adolescents With Relapsed/Refractory/Progressive Malignancies Treated With Molecularly Informed Targeted Drugs in the Pediatric Precision Oncology Registry INFORM.

PURPOSE: INFORM is an international pediatric precision oncology registry, prospectively collecting molecular and clinical data of children with recurrent, progressive, or very high-risk malignancies. We have previously identified a subgroup of patients with improved outcomes on the basis of molecular profiling. The present analysis systematically investigates progression-free survival (PFS) and overall survival (OS) of patients receiving matching targeted treatment (MTT) with the most frequently applied drug classes and its correlation with underlying molecular alterations. METHODS: A cohort of 519 patients with relapsed or refractory high-risk malignancies who had completed a follow-up of at least 2 years or shorter in the case of death or loss to follow-up was analyzed. Survival times were compared using the log-rank test. RESULTS: MTT with anaplastic lymphoma kinase (ALK), neurotrophic tyrosine receptor kinase (NTRK), and B-RAF kinase (BRAF) inhibitors showed significantly improved PFS (P = .012) and OS (P = .036) in comparison with conventional treatment or no treatment. However, analysis of the four most commonly applied MTT groups, mitogen-activated protein kinase (MEK- n = 19), cyclin-dependent kinase (CDK- n = 23), other kinase (n = 62), and mammalian-target of rapamycin (mTOR- n = 20) inhibitors, did not reveal differences in PFS or OS compared with conventional treatment or no treatment in patients with similar molecular pathway alterations. We did not observe differences in the type of pathway alterations (eg, copy number alterations, single-nucleotide variants, InDels, gene fusions) addressed by MTT. CONCLUSION: Patients with respective molecular alterations benefit from treatment with ALK, NTRK, and BRAF inhibitors as previously described. No survival benefit was observed with MTT for mutations in the MEK, CDK, other kinase, or mTOR signaling pathways. The noninterventional character of a registry has to be taken into account when interpreting these data and underlines the need for innovative interventional biomarker-driven clinical trials in pediatric oncology.

Profile of Luspatercept in the Treatment of Anemia in Adults with Non-Transfusion-Dependent ß-Thalassemia (NTDT): Design, Development and Potential Place in Therapy.

Over the past decade, evidence has been mounting on the detrimental clinical sequelae of untreated anemia in patients with non-transfusion-dependent ß-thalassemia (NTDT). There are no pharmacologic agents that are specifically approved for the management of anemia in NTDT, and available options such as splenectomy, transfusion therapy, and hydroxyurea each come with their own shortcomings, especially for long-term use. Luspatercept is an erythroid maturation agent that has been evaluated in a Phase 2, randomized trial and showed a significant benefit in raising hemoglobin level by at least 1 g/dL in adults with NTDT and a baseline hemoglobin level ≤10 g/dL. These data led to luspatercept's approval by the European Commission for the treatment of anemia in adults with NTDT and presents the first evidence-based approach for a novel agent that is able to ameliorate anemia in this patient population.

LOGGIC Core BioClinical Data Bank: Added clinical value of RNA-Seq in an international molecular diagnostic registry for pediatric low-grade glioma patients.

BACKGROUND: The international, multicenter registry LOGGIC Core BioClinical Data Bank aims to enhance the understanding of tumor biology in pediatric low-grade glioma (pLGG) and provide clinical and molecular data to support treatment decisions and interventional trial participation. Hence, the question arises whether implementation of RNA sequencing (RNA-Seq) using fresh frozen (FrFr) tumor tissue in addition to gene panel and DNA methylation analysis improves diagnostic accuracy and provides additional clinical benefit. METHODS: Analysis of patients aged 0 to 21 years, enrolled in Germany between April 2019 and February 2021, and for whom FrFr tissue was available. Central reference histopathology, immunohistochemistry, 850k DNA methylation analysis, gene panel sequencing, and RNA-Seq were performed. RESULTS: FrFr tissue was available in 178/379 enrolled cases. RNA-Seq was performed on 125 of these samples. We confirmed KIAA1549::BRAF-fusion (n = 71), BRAF V600E-mutation (n = 12), and alterations in FGFR1 (n = 14) as the most frequent alterations, among other common molecular drivers (n = 12). N = 16 cases (13%) presented rare gene fusions (eg, TPM3::NTRK1, EWSR1::VGLL1, SH3PXD2A::HTRA1, PDGFB::LRP1, GOPC::ROS1). In n = 27 cases (22%), RNA-Seq detected a driver alteration not otherwise identified (22/27 actionable). The rate of driver alteration detection was hereby increased from 75% to 97%. Furthermore, FGFR1 internal tandem duplications (n = 6) were only detected by RNA-Seq using current bioinformatics pipelines, leading to a change in analysis protocols. CONCLUSIONS: The addition of RNA-Seq to current diagnostic methods improves diagnostic accuracy, making precision oncology treatments (MEKi/RAFi/ERKi/NTRKi/FGFRi/ROSi) more accessible. We propose to include RNA-Seq as part of routine diagnostics for all pLGG patients, especially when no common pLGG alteration was identified.