Etuvetidigene autotemcel (WASKYRA™) is an autologous haematopoietic stem cell (HSC)-based gene therapy being developed by Fondazione Telethon for the treatment of Wiskott-Aldrich syndrome (WAS). In December 2025, etuvetidigene autotemcel was approved in the USA for the treatment of paediatric patients aged 6months and older and adults with WAS who have a mutation in the WAS gene for whom HSC transplantation (HSCT) is appropriate and no suitable human leukocyte antigen (HLA)-matched related stem cell donor is available. Etuvetidigene autotemcel was approved in the EU for the same indication in January 2026. This article summarizes the milestones in the development of etuvetidigene autotemcel leading to this first approval for the treatment of WAS.

Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency characterized by eczema, microthrombocytopenia, and recurrent infections. This study evaluates the frequency of clinical manifestations and overall outcomes in WAS patients, comparing those who received hematopoietic stem cell transplantation (HSCT) with those who did not. Thirty-eight boys with a definite diagnosis of WAS were retrospectively evaluated in the Immunology, Asthma, and Allergy Research Institute registry in Tehran from 2006 to 2023. The median ages at symptom onset, diagnosis, and delay to diagnosis were 3.5, 7.5, and 4.5 months, respectively. The clinical presentations include allergies in 38 (100%), infection in 37 (97.4%), hemorrhage in 36 (94.7%), autoimmunity in 14 (36.8%), and malignancies or myelodysplasia syndrome in 3 (7.9%) patients. Although microthrombocytopenia is a hallmark of WAS, 34.4% of our cases had normal platelet size. The WAS gene analysis in 36 of 38 patients identified six novel mutations. Sixteen patients underwent HSCT. Disease-free survival was reported in 10 (62.5%) of them, whereas 6 (37.5%) of them were deceased. The mortality rate in non-transplant patients was 15/22 (68.2%). Most WAS patients experienced atopy, recurrent infections, and bleeding. Moreover, autoimmunity and malignancies have increased relative to the general population. Moreover, the mortality rate is high, especially among those who did not receive HSCT. Keeping in mind that thrombocytopenia alongside eczema and/or infection in a male infant can be the presentation of this fatal disease. Early diagnosis and treatment could be lifesaving and prevent severe morbidities.

Wiskott-Aldrich syndrome (WAS) is a rare x-linked monogenic immunodeficiency disease, caused by the mutation of WAS gene encoding WAS protein (WASp). Previous findings in WAS patients show B cell perturbations in the periphery, characterized by diminished B-cell numbers and phenotype abnormalities, including reduced frequency of classical CD27+ memory B cells (MBCs), accompaniedby an unusual expansion of atypical CD21low MBCs. The mechanism underlying these abnormalities in MBCs developmental pathway has not been completely dissected. In this study, WASp knock-out mice undergone with acute lymphocytic choriomeningitis virus (LCMV) infection was used as a model to investigate the effects of WASp deficiency on the differentiation of MBCs and the possible mechanisms. We found that by day 11 after infection, the proportion of classical IgG2c+ MBCs was dramatically decreased, this was accompanied by a corresponding increase in the proportion of atypical CD21low MBCs. Using single-cell RNA sequencing (scRNA-seq), we also identified WASp deficiency promoted the formation of atypical MBCs during acute viral infection. Remarkably, our study revealed a marked reduction of WASp expression in atypical MBCs. Overall, our data show that WASp is differentially expressed in MBCs subsets, and manipulates the fate of MBCs during acute LCMV infection.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked primary immunodeficiency characterized by microthrombocytopenia, eczema, and recurrent infections. While autoimmune complications are common in WAS, including autoimmune hemolytic anemia, vasculitis, and glomerulonephritis, type 1 diabetes has not been previously described. We report a 37-year-old man with longstanding leukopenia and recurrent infections who was diagnosed with WAS after genetic testing revealed a gain-of-function mutation in the WAS gene. During pre-transplant evaluation for hematopoietic stem cell transplantation, he was incidentally found to have a blood glucose level over 600 mg/dL and an A1c of 12.8%, along with classic symptoms of new-onset diabetes. Antibody testing confirmed autoimmune diabetes with elevated GAD65 and ZnT8 antibodies, and C-peptide of 1.2 ng/mL, with a glucose of 186 mg/dL. He was started on intravenous insulin and later discharged home on a basal-bolus regimen. To our knowledge, this is the first reported case of GAD65 and ZnT8 positive autoimmune diabetes in a patient with WAS. This case expands the spectrum of autoimmune disease associated with WAS and underscores the importance of maintaining a high index of suspicion for atypical autoimmune presentations in patients with WAS.

Wiskott-Aldrich Syndrome (WAS) is a rare X-linked immunodeficiency characterized by microthrombocytopenia, eczema, and recurrent infections. In addition to this classical triad, recent studies have emphasized the roles of immune dysregulation, autoimmunity, chronic inflammation, endothelial dysfunction, and increased susceptibility to infections. These factors contribute to a broader disease spectrum that may involve not only bleeding complications but also, in rare instances, thrombotic events. In this review, we present three siblings from the same family affected by WAS. Two of them were genetically confirmed to carry the c. mutation in the WAS gene; however, they exhibited markedly different clinical phenotypes. One presented severe thrombocytopenia and eczema, while the other developed retinal artery occlusion and thrombotic manifestations. The third sibling, although not genetically tested, died from fulminant sepsis following splenectomy for presumed immune thrombocytopenia, with clinical findings strongly suggestive of undiagnosed WAS. Through these illustrative cases, we explore the pathophysiological mechanisms underlying WAS, focusing on platelet dysfunction, autoimmune phenomena, infection susceptibility, and vascular complications. We also briefly review current treatment options, including hematopoietic stem cell transplantation, gene therapy, and novel immunomodulatory strategies. This case-based review highlights the phenotypic heterogeneity of WAS, the limitations of genotype-based predictions, and the importance of individualized management. A better understanding of the immunologic, infectious, and vascular aspects of the disease may facilitate earlier diagnosis and guide clinical decision-making in this complex disorder.

Introduction IEIs are a heterogeneous group of primarily inherited genetic disorders characterized by impaired immune system function. While most genetic alterations are single nucleotide variants (SNVs), some cases are caused by larger genomic changes such as insertions or deletions that lead to copy number variations (CNVs). To identify potential large deletions in the WAS gene, we developed a molecular strategy combining a novel own design multiplex ligation-dependent probe amplification (MLPA) assay specific to WAS with a droplet digital PCR (ddPCR) assay. Methods Three patients with suspected Wiskott–Aldrich syndrome (WAS) were studied. Initial analysis involved Sanger sequencing. When a CNV was suspected, additional methodologies were incorporated: a WAS-specific MLPA test (covering exons 1, 2, 3, 4, 5, 6, and 8) designed according to the manufacturer’s recommendations and a ddPCR assay targeting designed exons 7, 8, 9, and 12. Results None of the patients showed amplification of individual WAS exons by PCR. MLPA analysis revealed a complete absence of all exons in two patients, while the third patient showed absence of exon 8 by MLPA and absence of exons 7, 8, 9, and 12 by ddPCR. Both methodologies allowed for the analysis of women carriers of this X-linked hereditary pathology, leading to the identification of a carrier. Conclusions These patients clearly demonstrate the importance of having more than one screening strategy for efficient diagnosis and family genetic counseling, mostly in cases where the clinical suspicion is very strong but conventional diagnostic strategies yield negative results. In many IEIs, bioinformatic algorithms in next-generation sequencing studies detect potential CNVs that need to be confirmed. Both MLPA and ddPCR are complementary techniques that would allow for a definitive diagnosis in these cases.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked recessive disorder characterized by microthrombocytopenia, eczema, recurrent infections, and immune dysregulation, affecting approximately 1 in 100,000 live births. While the disorder was historically fatal in early childhood, advances in hematopoietic stem cell transplantation (HSCT), gene therapy, and supportive care have improved survival, though morbidity remains high. Mutations in the WAS gene disrupt the WAS protein (WASp), which is essential for actin cytoskeleton dynamics, thereby impairing immune cell function. Over 466 mutations correlate with disease severity, from severe classic WAS to milder X-linked thrombocytopenia (XLT). Supportive therapies manage symptoms, while HSCT offers a cure for severe cases. Gene therapy has emerged as a promising alternative, with early gamma-retroviral trials showing efficacy but also a risk of leukemogenesis. Third-generation lentiviral vectors with self-inactivating LTRs (long terminal repeats) demonstrate improved safety and immune restoration in clinical trials. This review evaluates the evolution of gene therapy for WAS, from early trials to emerging genome editing approaches, assessing their efficacy, safety, and potential to transform clinical outcomes.

Genomic characteristics of diffuse large B-cell lymphoma associated with Wiskott-Aldrich syndrome

Lentiviral hematopoietic stem and progenitor cell gene therapy for Wiskott-Aldrich Syndrome: Early access experience in Italian patients based on 648/1996 law

The clinical spectrum of X-linked thrombocytopenia (XLT)/ Wiskott-Aldrich syndrome (WAS) is broad, ranging from mild, intermittent thrombocytopenia to the classical severe phenotype characterized by eczema, infections, and thrombocytopenia. Patients with XLT often lack the complete triad but manifest with thrombocytopenia-associated bleeding and are hence misdiagnosed as chronic immune thrombocytopenia (ITP). Moreover, the clinical picture is further complicated by the development of autoimmune cytopenia. Early identification is critical, as definitive treatment with hematopoietic stem cell transplantation (HSCT) can be offered, and unnecessary immunosuppressive therapies, including corticosteroids, can be avoided. In this study, the authors screened a cohort of boys with chronic ITP using flow cytometry-based WASp protein expression analysis, followed by genetic testing. Among 38 patients evaluated, 5 (13.5%) had pathogenic variants in the WAS gene. Clinical features such as X-linked family history, eczema, low mean platelet volume (MPV), or reduced WASp expression in chronic ITP patients with suboptimal response to immunomodulatory drugs should prompt genetic evaluation for WAS.

Ex-vivo gene therapies require scalable, high-quality lentivirus (LV) with excellent transduction efficiency. Achieving this involves a synergistic approach combining efficient vector design and LV process optimization. In our study, we evaluated transfection reagents for generating stable producer cell lines from two Tet-off regulated adherent stable LV packaging PCLs, GPRG and GPRTG, to produce lentivirus (LV) to treat Wiskott Aldrich Syndrome (WAS). Stable producer cell lines expressing the WAS transgene or GFP transgene were generated from GPRG and GPRTG PCLs. The GPRTG producer cell line showed 6-fold higher LV titer and resulted in better transduction of CD34+ cells. Further, we optimized the LV production process in continuous perfusion and recirculation mode and compared three technologies: traditional flatware systems, iCELLis™ Nano and scale-X™ Hydro Univercells adherent bioreactors using GPRTG stable producer cell line. Scale-X™ Hydro outperformed iCELLis™ Nano in LV productivity per surface area (TU/cm2). We successfully scaled up LV production from Scale-X™ Hydro (2.4 m2) to Scale-X™ Carbo (10 m2), producing 1.13E+12 TU per 10 m2 through 7 harvests using the continuous perfusion process. This process produced LV that efficiently transduced CD34+ cells, achieving a vector copy number (VCN) of upto 4 at a Multiplicity of Infection (MOI) of 10. Our study has successfully established a scalable, cost-effective and robust platform for LV production, demonstrating its potential for clinical applications.

Unraveling a novel missense mutation (c.A248C) in Wiskott-Aldrich syndrome gene by whole exome sequencing: Insights from dynamic simulation, molecular docking and in-silico studies.

Wiskott-Aldrich Syndrome (WAS) is a rare and severe X-linked immunodeficiency disorder characterized by microthrombocytopenia, eczema, and increased susceptibility to infections, autoimmunity, and malignancies. This study aims to explore molecular changes in the WAS gene in Brazilian patients and assess their correlation with clinical manifestations and disease severity. Thirty-one patients from 27 families with thrombocytopenia suspected to have WAS or X-linked thrombocytopenia (XLT) were analyzed. Clinical evaluation, cell morphology analysis, and flow cytometry (when feasible) were performed. DNA samples underwent direct sequencing to identify WAS gene mutations. Genomic sequencing identified 17 WAS gene variants, 10 of which were novel, expanding the genetic diversity of the disorder. The most frequent WAS gene variants were primarily frameshift indels that introduced premature stop codons, with five localized in exon 10. While thrombocytopenia and small platelets were prevalent, atypical presentations, including one patient with normal platelet size, were observed. The correlation between genotype and phenotype was complex, as some patients harboring similar mutations demonstrated varying disease severities. Of the 22 confirmed cases, 12 underwent hematopoietic stem cell transplantation (HSCT), while six succumbed to severe disease complications, including opportunistic infections and malignancies. The study underscores the need for early molecular diagnosis and tailored treatments, particularly HSCT, which remains the standard curative therapy. Additionally, the findings emphasize the role of genetic variation in predicting disease severity, underlining the importance of personalized medical approaches for WAS patients.

Long-term outcome in Wiskott-Aldrich syndrome and X-linked thrombocytopenia patients: an observational -prospective multi-center study of the Italian Primary Immune Deficiency Network (IPINET).

Wiskott-Aldrich syndrome (WAS) is a severe X-linked disorder caused by loss-of-function mutations in the WAS gene, responsible for encoding WAS protein (WASP), a key regulator of the actin cytoskeleton in all hematopoietic cells, except red blood cells. The mechanism underlying microthrombocytopenia, a distinctive feature of WAS and a major contributor to mortality, remains not fully elucidated. In this study, using different gene-editing strategies, we corrected mutations in patient-derived WAS-induced pluripotent stem cell (iPSC) lines, generating isogeneic WAS-iPSC lines. These included lines with direct mutation-specific correction and lines incorporating a WASP transgene cassette regulated by the MND or WAS1.6 kb promoter integrated at the safe harbor AAV1 site. Our results demonstrated that direct mutation correction successfully restored WASP levels to the equivalent of the wild-type in iPSC-derived megakaryocytes (MKs). In contrast, the AAV1-targeted strategy using the MND and WAS1.6 promoters yielded a lower level of WASP. Notably, only the mutation-specific correction lines exhibited improvements in proplatelet structures and generated larger-sized platelets. Our findings underscore the crucial roles of WASP during human thrombopoiesis and suggest that therapeutic approaches, such as direct gene correction, which can achieve physiologic levels of WASP in MKs, hold promise for ameliorating platelet defects in individuals with WAS.

Abstract Background: Wiskott–Aldrich syndrome (WAS) is a rare X-linked disorder characterized by immunodeficiency, thrombocytopenia, and eczema, with a risk of autoimmune phenomena. Clinical Description: A 3-year-old boy presented to us with a history of recurrent skin and mucosal bleeds, itchy skin lesions, and recurrent purulent ear discharge. He had been hospitalized for pneumonia and meningitis earlier, having developed left-sided hemiplegia associated with a cerebral infarct. On examination, he was growth retarded with pallor, hepatosplenomegaly, multiple purpuric spots, and infected scalp lesions. In addition, he had spastic hemiparesis in the left side. Management and Outcome: Investigation revealed microcytic hypochromic anemia, eosinophilia, thrombocytopenia, and very high IgE titer (10,433). Coagulation profile was normal. Tuberculosis work-up was negative. The mean platelet volume was low normal (7.3) and bone marrow showed decreased number and size of megakaryocytes. Exome sequencing showed pathogenic mutation of WAS gene in exon 3 hemizygous XLR variant. The patient received weekly intravenous immunoglobulin therapy and cotrimoxazole. The eczema, thrombocytopenia, and infections improved. Later, he developed sudden-onset bilateral loss of vision. Magnetic resonance (MR) imaging brain revealed acute infarct on the left occipital region and gliosis in the right cerebral hemisphere with MR angiography showing middle and posterior cerebral artery thrombosis and narrowing of bilateral distal internal carotid arteries suggestive of moyamoya disease. Immunosuppressive agents and antiplatelets could not be administered, so the child was kept under supportive care. Conclusion: This case makes pediatricians aware of the possibility of cerebrovascular events as a manifestation of autoimmune vasculitis in children with WAS. Optimal treatment for such cases needs research.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked genetic disorder caused by a mutation in the WAS gene that codes for the WASp protein, which is involved in the functioning of the cytoskeleton of non-erythroid haematopoietic cells. This mutation leads to a congenital immunity disorder characterised by immunodeficiency, microthrombocytopenia and eczema. Its incidence is 1 in 250,000 live-born males. Treatment options to date are haematopoietic stem cell transplantation (HSCT) from an HLA-matched donor or gene therapy. The paper described the case of Tommaso, a 5-month-old first-born child with WAS who represented a diagnostic challenge. At onset, the infant did not present with any pathognomonic elements of classic WAS, but a picture of trilinear cytopenia with severe anaemia. Only one single case is described in literature with the same genotype as Tommaso (WAS c.257G>A p. Arg86His) but characterised by a heterogeneous phenotype and different onset symptoms. The specific and timely diagnosis of WAS allowed Tommaso, at only 5 months of age, to undergo gene therapy, thus achieving a real recovery from the syndrome and significantly reducing the risks related to the toxicity of non-targeted therapies to which he would have been exposed in the future. This case teaches how the clinician must remain critical and inquisitive in the diagnostic process, always aiming to reach a specific diagnosis in order to start a targeted therapeutic programme in the shortest time possible.

Multisystem inflammatory syndrome in children (MIS-C) has been reported in patients with inborn errors of immunity (IEI), providing insights into disease pathogenesis. Here, we present the first case of MIS-C in a child affected by Wiskott-Aldrich syndrome (WAS) gene mutation, elucidating underlying predisposing factors and the involved inflammatory pathways. Genetic analysis revealed a frameshift truncating variant in the WAS gene, resulting in WAS protein expression between mild and severe forms, despite a clinical phenotype resembling X-linked thrombocytopenia (XLT). IL-1β secretion by LPS-stimulated peripheral blood mononuclear cells from patient during MIS-C was lower compared to healthy subjects but increased during follow-up. Conversely, the percentage of ASC (apoptosis-associated speck-like protein containing a CARD) specks in the patient's circulating monocytes during the acute phase was higher than in healthy subjects. The type I interferon (IFN) signature during MIS-C was normal, in contrast to the raised IFN signature measured far from the acute event. This case supports the association of IEI with MIS-C, potentially linked to delayed immune responses to SARS-CoV-2. The XLT phenotype underlies a subclinical immunodysregulation involving the NLRP3 inflammasome and the type-I IFN response.

Haploidentical Bone Marrow Transplantation for Wiskott-Aldrich Syndrome

Detailed knowledge of human B-cell development is crucial for the proper interpretation of inborn errors of immunity and malignant diseases. It is of interest to understand the kinetics of protein expression changes during development, but also to properly interpret the major and possibly alternative developmental trajectories. We have investigated human samples from healthy individuals with the aim of describing all B-cell developmental trajectories. We validated a 30-parameter mass cytometry panel and demonstrated the utility of "vaevictis" visualization of B-cell developmental stages. We used the trajectory inference tool "tviblindi" to exhaustively describe all trajectories leading to all developmental ends discovered in the data. Focusing on Natural Effector B cells, we demonstrated the dynamics of expression of nuclear factors (PAX-5, TdT, Ki-67, Bcl-2), cytokine and chemokine receptors (CD127, CXCR4, CXCR5) in relation to the canonical B-cell developmental stage markers. We observed branching of the memory development, where follicular memory formation was marked by CD73 expression. Lastly, we performed an analysis of two example cases of abnormal B-cell development caused by mutations in RAG-1 and Wiskott-Aldrich syndrome gene in patients with primary immunodeficiency. In conclusion, we developed, validated, and presented a comprehensive set of tools for the investigation of B-cell development in the bone marrow compartment.