Melike Sezgin Evim

Background: Inherited platelet disorders (IPDs) are a heterogeneous group of diseases characterized by thrombocytopenia and/or platelet functional abnormalities. This study aimed to identify novel candidate genes associated with hereditary thrombocytopenia using whole‐exome sequencing (WES). Methods: WES was performed in 40 patients with suspected IPDs. Functional characterization included segregation analysis, platelet‐based immunoblotting, and in silico structural modeling. Results: Rare variants in known IPD‐associated genes were identified in 32 patients (80%). Reanalysis of unresolved cases identified a novel homozygous ITGA10 (NM_003637.5) variant (c.2248C>T; p.Leu750Phe) in a 5‐year‐old female with severe thrombocytopenia. ITGA10 encodes the α10 subunit of the α10β1 integrin complex and is located within the recurrent 1q21.1 microdeletion region associated with thrombocytopenia‐absent radius syndrome. Immunoblotting studies demonstrated mildly reduced ITGA10 expression, an additional ∼80 kDa ITGA10‐related band, markedly reduced ITGB1 expression, and absence of β‐actin expression in platelet lysates despite wild‐type ACTB and ITGB1 genotypes. In silico structural analysis predicted reduced protein stability and impaired conformational flexibility associated with the p.Leu750Phe substitution. Conclusions: These findings support ITGA10 as a novel candidate gene for inherited thrombocytopenia and suggest that disruption of the ITGA10–ITGB1 integrin complex may contribute to abnormal platelet homeostasis and cytoskeletal organization. Further functional studies and additional patients will be important to clarify the biological mechanisms and establish the role of ITGA10 in inherited thrombocytopenia.

Ph-like ALL, a high-risk subgroup of B-cell ALL, is associated with a poor prognosis. The genetic diversity observed across different ethnicities underscores the importance of population-specific studies to gain a deeper understanding of its genetic drivers and clinical outcomes. This study aims to characterize the Ph-like ALL group in Turkish pediatric B-ALL patients and evaluate our custom-developed gene panel for subgroup identification. To identify the Ph-like subgroup, RNA was isolated from 35 bone marrow samples, and targeted mRNA expression analysis was performed by RT-qPCR using a custom-designed panel consisting of 96 genes. Additionally, the Archer FusionPlex ALL Panel (ArcherDX, Boulder, CO) was employed for further evaluation of patients demonstrating the highest similarity rates. This study employed a gene panel designed to differentiate Turkish Ph-like ALL patients within the Ph-negative group, identifying two Ph-like cases (6%). The panel demonstrated 96.9% sensitivity and 93.9% specificity in detecting Ph-like ALL, highlighting its effectiveness in differential diagnosis. In the Ph-like cases, alterations in PAX5 (rs143723948, rs879020782) and IKZF1 (rs6975767) were observed. Both cases shared a novel EPOR variant (rs1312770718), with no known clinical impact. Additionally, a novel variantin the PTPN11 gene was interpreted as “Possibly Damaging”. This study introduces a gene profiling-based diagnostic approach for the Ph-like subgroup of pediatric B-ALL in Turkish patients. The integration of targeted tyrosine kinase inhibitors into treatment protocols, guided by the diagnostic algorithm, aims to improve prognosis and survival, advancing personalized management of Ph-like ALL.

Background: GNE mutations are rare pathologic conditions that can cause severe thrombocytopenia and bleeding tendency from the neonatal period. The clinical presentation of patients with GNE mutations varies from mild skin and mucosal bleeding to life-threatening bleeding. Case Presentation: This study reported two siblings with hereditary thrombocytopenia. The 2 patients exhibited severe thrombocytopenia (platelet [PLT] count: A [p.Gly559Arg]) was detected in GNE . One sibling was unresponsive to the platelet receptor agonists eltrombopag and romiplostim. Meanwhile, the other sibling was unresponsive to eltrombopag but was responsive to romiplostim. Conclusion: The first-line treatment of patients with GNE mutations is PLT transfusion. However, the management of patients with severe thrombocytopenia and frequent bleeding is challenging. Thrombopoietin receptor agonists are administered to these patients to mitigate the risk of alloimmunization and PLT transfusion refractoriness. However, the observed responses may differ even in siblings carrying the same mutation. This differential response may be related to bone marrow megakaryocyte reserves and hepatocyte Aswell-Morell receptor levels.

Background: In patients with acute lymphoblastic leukemia (ALL), the risk of thromboembolism increases due to hemostatic changes secondary to the primary disease and due to treatment‐related factors. In this multicenter study, we aimed to research the frequency of central nervous system (CNS) thrombosis occurring during treatment, hereditary and acquired risk factors, clinical and laboratory features of patients with thrombosis, treatment approaches, and thrombosis‐related mortality and morbidity rates in pediatric ALL patients.Procedure: Pediatric patients who developed CNS thrombosis during ALL treatment from 2010 to 2021 were analyzed retrospectively in 25 different Pediatric Hematology Oncology centers in Türkiye. The demographic characteristics of the patients, symptoms associated with thrombosis, the stage of the leukemia treatment during thrombosis, the anticoagulant therapy applied for thrombosis, and the final status of the patients recorded through electronic medical records were determined.Results: Data from 70 patients with CNS thrombosis during treatment, out of 3968 pediatric patients with ALL, were reviewed. The incidence of CNS thrombosis was 1.8% (venous: 1.5 %; arterial: 0.03%). Among patients with CNS thrombosis, 47 had the event in the first 2 months. Low molecular weight heparin (LMWH) was the most commonly used treatment with a median of 6 months (min–max: 3–28 months). No treatment‐related complications occurred. Chronic thrombosis findings occurred in four patients (6%). In five (7%) patients who developed cerebral vein thrombosis, neurological sequelae (epilepsy and neurological deficit) remained. One patient died related to thrombosis, and the mortality rate was 1.4%.Conclusion: Cerebral venous thrombosis and, less frequently, cerebral arterial thrombosis may develop in patients with ALL. The incidence of CNS thrombosis is higher during induction therapy than during other courses of treatment. Therefore, patients receiving induction therapy should be monitored carefully for clinical findings suggestive of CNS thrombosis.

Background: Data on the outcome and risk factors of pediatric patients with SARS-CoV-2 infection (COVID-19) following hematopoietic stem cell transplantation (HSCT) are limited. Objectives: We aimed to describe risk factors for a severe course and mortality. Method: In this nationwide study, data were collected retrospectively from 28 transplant centers. Results: One hundred ninety-six children [(63.8% male; median age 8.75 (IQR, 4.86-14.30)] who received allogeneic (n: 184, 93.9%) or autologous (n: 12, 6.1%) HSCT were included. The median time from HSCT to SARS-CoV-2 infection was 207.5 days (IQR, 110.2-207.5). The most common clinical manifestation was fever (58.2%), followed by cough (33.7%); 43 cases (21.9%) were asymptomatic. Lower respiratory tract disease (LRTD) and multisystem inflammatory syndrome in children (MIS-C) developed in 58 (29.6%) and 8 (4.1%) patients, respectively. Twenty-six patients (13.3%) required ICU admission. Nine patients died at a median of 17 days (min-max 1-33) after COVID-19 diagnosis, 6 of whom died due to the disease, with a COVID-19 lethality rate of 3.1%. The 6-week overall survival was 95.4% (95% CI 92.5-98.3). Multivariate analysis found that HSCT with a mismatched donor (OR, 8.98, p: 0.039) and LRTD (OR, 61.55, p: 0.001) were independent risk factors for ICU admission; MIS-C (OR, 9.55, p: 0.044) and lymphopenia (OR, 4.01, p: 0.030) at diagnosis were risk factors for mortality. Conclusion: Overall mortality was lower in children than in adult counterparts, and HSCT with a mismatched donor, lymphopenia, LRTD, MIS-C and ICU admission were important risk factors for adverse outcomes.