Deficiency of Adenosine Deaminase 2.

Adenosine deaminase 2 (ADA2) deficiency is an autosomal recessively inherited autoinflammatory disorder caused by loss-of-function mutations in the ADA2 gene. Although the pathogenesis involves triggering of a proinflammatory cascade due to increased production of inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and the process of neutrophil extracellular traps formation (NETosis) dysregulation resulting from an excess accumulation of extracellular adenosine, the pathogenetic mechanism still needs further clarification, due to the broad clinical spectrum. In addition to the initially described vasculitis-related symptoms, hematologic, immunologic, and autoinflammatory symptoms are now well-recognized. The diagnosis is made by demonstration of pathogenic variants of ADA2 with biallelic loss of function and identification of low plasma ADA2 catalytic activity. Currently, TNF alpha inhibitors are the treatment of choice for controlling vasculitis manifestations and preventing strokes. In patients presenting with severe hematologic findings, TNF alpha inhibitors are not the treatment of choice, and hematopoietic stem cell transplantation has been shown to be successful in selected cases. Recombinant ADA2 protein and gene therapy are promising treatment modalities for the future. In conclusion, ADA2 has a broad phenotype and should be considered in the differential diagnosis in different clinical situations. In this review, we aimed to summarize the disease manifestations of ADA2 deficiency and available treatment options.

Associated Congenital Abnormalities and Physical Phenotype in Patients with Diamond-Blackfan Anemia May Be Overlooked.

Diamond-Blackfan anemia (DBA) is a rare and inherited form of erythroid aplasia, characterized by severe macrocytic anemia, congenital malformations, and predisposition to cancer. The purpose of this study is to determine the congenital abnormalities and dysmorphological features of DBA patients in a cross-sectional manner. The study group included patients who had diagnosis of DBA between 1983 and 2017. Dysmorphological examinations of the patients were performed by an experienced dysmorphologist and also echocardiography and abdominal ultrasonography were performed in order to figure out cardiac and urogenital abnormalities. A total of 45 patients were examined in this study. Dysmorphological examination, echocardiography, and abdominal ultrasonography revealed the rate of congenital abnormalities as high as 88.7%. In consideration of the congenital abnormalities, the most common findings were craniofacial, followed by skeletal abnormalities. The rate of anomalies was found higher in our series of patients than that have been previously reported, most probably due to the evaluations being performed by a dysmorphologist in our cohort and not only depending on patient records or hematologists' physical examination.

Dominant Beta Thalassemia: A Very Rare Cause of Thalassemia in a Mediterranean Country.

Beta thalassemia is one of the monogenic disorders characterized by decreased production of ß-globin chains and various types of mutations have been reported to cause thalassemia phenotype. On the other hand, rare mutations also affect and diversify the disease spectrum. Herein, we present an anemic patient from Turkey diagnosed with dominant ß thalassemia due to a heterozygous mutation in exon 3 of the HBB gene.

The Outcome of Modified St. Jude Total XV Protocol in Turkish Children with Newly Diagnosed Acute Lymphoblastic Leukemia: A Single-Center Retrospective Analysis.

Objective: This study examines the prognostic factors and outcomes of Turkish children with newly diagnosed acute lymphoblastic leukemia (ALL) who were treated with Modified St. Jude Total XV Protocol, which was modified by adding high-dose methylprednisolone (HDMP) before induction in the original protocol. Materials and Methods: A cohort of 183 newly diagnosed ALL patients aged 1-18 years received Modified St. Jude Total XV Therapy between January 1, 2008 and January 30, 2016. HDMP was administered for 7 days, with randomized doses at 10 or 20 mg/kg/d, tapered during the subsequent 7 days to 5 and 10 mg/kg/d, followed by 2 mg/kg/d for 2 weeks. Absolute blast count in peripheral blood and minimal residual disease (MRD) in bone marrow were assesses at the end of the initial HDMP treatment (Day 7). MRD in the bone marrow was measured on day 15 and at the end of the induction period. These patients were followed until July 15, 2019. Results: The five-year event-free (EFS) and overall survival (OAS) rates for all patients were 85.6±2.6% and 89.2±2.3%, respectively. The steroid good responder rate (<1 000/mm3 absolute blast count in peripheral blood on Day 7) was 88%, with 97% of children achieving complete remission post-induction. No significant differences were observed between the two groups in survival rate and infection frequency. EFS and OAS correlated with initial leukocyte count, age 10-18 years at diagnosis, CD20 positivity at diagnosis, and gram-negative bacterial infection during remission induction. Conclusion: The notable response rates on day 7 and 15, along with encouraging EFS and OAS outcomes with Modified St. Jude Total XV in childhood ALL patients underscore the early and high response effect of HDMP. Short-term HDMP can be initiated at the onset of induction, administered at 10 mg/kg/day for the initial 7 days, aiming to minimize potential side effects.

Efficacy of T cell assays for the diagnosis of primary defects in cytotoxic lymphocyte exocytosis.

Primary hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder associated with autosomal recessive variants in genes required for perforin-mediated lymphocyte cytotoxicity. A rapid diagnosis is crucial for successful treatment. Although defective cytotoxic T lymphocyte (CTL) function causes pathogenesis, quantification of natural killer (NK) cell exocytosis triggered by K562 target cells currently represents a standard diagnostic procedure for primary HLH. We have prospectively evaluated different lymphocyte exocytosis assays in 213 patients referred for evaluation for suspected HLH and related hyperinflammatory syndromes. A total of 138 patients received a molecular diagnosis consistent with primary HLH. Compared to routine K562 cell-based assays, assessment of Fc receptor-triggered NK-cell and T cell receptor-triggered CTL exocytosis displayed higher sensitivity and improved specificity for the diagnosis of primary HLH, with these assays combined providing a sensitivity of 100% and specificity of 98.3%. By comparison, NK-cell exocytosis following K562 target cell stimulation displayed a higher inter-individual variability, in part explained by differences in NK-cell differentiation or large functional reductions following shipment. We thus recommend combined analysis of T cell receptor-triggered CTL and Fc receptor-triggered NK-cell exocytosis for the diagnosis of patients with suspected familial HLH or atypical manifestations of congenital defects in lymphocyte exocytosis.

Recommendations for diagnosis, treatment, and prevention of iron deficiency and iron deficiency anemia.

Iron is an essential nutrient and a constituent of ferroproteins and enzymes crucial for human life. Generally, nonmenstruating individuals preserve iron very efficiently, losing less than 0.1% of their body iron content each day, an amount that is replaced through dietary iron absorption. Most of the iron is in the hemoglobin (Hb) of red blood cells (RBCs); thus, blood loss is the most common cause of acute iron depletion and anemia worldwide, and reduced hemoglobin synthesis and anemia are the most common consequences of low plasma iron concentrations. The term iron deficiency (ID) refers to the reduction of total body iron stores due to impaired nutrition, reduced absorption secondary to gastrointestinal conditions, increased blood loss, and increased needs as in pregnancy. Iron deficiency anemia (IDA) is defined as low Hb or hematocrit associated with microcytic and hypochromic erythrocytes and low RBC count due to iron deficiency. IDA most commonly affects women of reproductive age, the developing fetus, children, patients with chronic and inflammatory diseases, and the elderly. IDA is the most frequent hematological disorder in children, with an incidence in industrialized countries of 20.1% between 0 and 4 years of age and 5.9% between 5 and 14 years (39% and 48.1% in developing countries). The diagnosis, management, and treatment of patients with ID and IDA change depending on age and gender and during pregnancy. We herein summarize what is known about the diagnosis, treatment, and prevention of ID and IDA and formulate a specific set of recommendations on this topic.

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.

Unveiling the genetic landscape of suspected congenital dyserythropoietic anemia type I: A retrospective cohort study of 36 patients.

Congenital Dyserythropoietic Anemia type I (CDA I) is a rare hereditary condition characterized by macrocytic/normocytic anemia, splenomegaly, iron overload, and distinct abnormalities during late erythropoiesis, particularly internuclear bridges between erythroblasts. Diagnosis of CDA I remains challenging due to its rarity, clinical heterogeneity, and overlapping phenotype with other rare hereditary anemias. In this case series, we present 36 patients with suspected CDA I. A molecular diagnosis was successfully established in 89% of cases, identifying 16 patients with CDA I through the presence of 18 causative variants in the CDAN1 or CDIN1 genes. Transcriptomic analysis of CDIN1 variants revealed impaired erythroid differentiation and disruptions in transcription, cell proliferation, and histone regulation. Conversely, 16 individuals received a different diagnosis, primarily pyruvate kinase deficiency. Comparisons between CDA I and non-CDA I patients revealed no significant differences in erythroblast morphological features. However, hemoglobin levels and red blood cell count differed between the two groups, with non-CDA I subjects being more severely affected. Notably, most patients with severe anemia belonged to the non-CDA I group (82% non-CDA I vs. 18% CDA I), with a subsequent absolute prevalence of transfusion dependency among non-CDA I patients (100% vs. 41.7%). All patients exhibited reduced bone marrow responsiveness to anemia, with a more pronounced effect observed in non-CDA I patients. Erythropoietin levels were significantly higher in non-CDA I patients compared to CDA I patients. However, evaluations of erythroferrone, soluble transferrin receptor, and hepcidin revealed no significant differences in plasma concentration between the two groups.

Identification of the molecular etiology in rare congenital hemolytic anemias using next-generation sequencing with exome-based copy number variant analysis.

OBJECTIVES: In congenital hemolytic anemias (CHA), it is not always possible to determine the specific diagnosis by evaluating clinical findings and conventional laboratory tests. The aim of this study is to evaluate the utility of next-generation sequencing (NGS) and clinical-exome-based copy number variant (CNV) analysis in patients with CHA. METHODS: One hundred and forty-three CHA cases from 115 unrelated families referred for molecular analysis were enrolled in the study. Molecular analysis was performed using two different clinical exome panels in 130 patients, and whole-exome sequencing in nine patients. Exome-based CNV calling was incorporated into the traditional single-nucleotide variant and small insertion/deletion analysis pipeline for NGS data in 92 cases. In four patients from the same family, the PK Gypsy variant was investigated using long-range polymerase chain reaction. RESULTS: Molecular diagnosis was established in 86% of the study group. The most frequently mutated genes were SPTB (31.7%) and PKLR (28.5%). CNV analysis of 92 cases revealed that three patients had different sizes of large deletions in the SPTB and six patients had a deletion in the PKLR. CONCLUSIONS: In this study, NGS provided a high molecular diagnostic rate in cases with rare CHA. Analysis of the CNVs contributed to the diagnostic success.

Iron Deficiency Anemia in Infancy, Childhood, and Adolescence.

Iron deficiency is the most common nutrient deficiency in the world. Epidemiological data indi- cate that iron deficiency is more prevalent in infants, in preschool-children, and in adolescents. Etiologies of iron deficiency in children include inadequate dietary iron intake, which is the most common cause, as well as increased iron requirements, bleeding, and intestinal iron absorption disorders. Iron deficiency can lead to symptoms related to anemia, may interfere with neuro- development and may cause skin, hair, nail, and gastrointestinal problems. This review focuses on the causes, signs, symptoms, diagnosis and management of iron deficiency in infancy, child- hood, and adolescence.

Multiparametric analysis of etoposide exposed mesenchymal stem cells and Fanconi anemia cells: implications in development of secondary myeloid malignancy.

Secondary acute myeloid leukemia (sAML) may develop following a prior therapy or may evolve from an antecedent hematological disorder such as Fanconi Anemia (FA). Pathophysiology of leukemic evolution is not clear. Etoposide (Eto) is a chemotherapeutic agent implicated in development of sAML. FA is an inherited bone marrow (BM) failure disease characterized by genomic instability and xenobiotic susceptibility. Here, we hypothesized that alterations in the BM niche may play a critical/driver role in development of sAML in both conditions. Expression of selected genes involved in xenobiotic metabolism, DNA double-strand break response, endoplasmic reticulum (ER) stress, heat shock response and cell cycle regulation were determined in BM mesenchymal stem cells (MSCs) of healthy controls and FA patients at steady state and upon exposure to Eto at different concentrations and in recurrent doses. Expression of CYPA1, p53, CCNB1, Dicer1, CXCL12, FLT3L and TGF-Beta genes were significantly downregulated in FA-MSCs compared with healthy controls. Eto exposure induced significant alterations in healthy BM-MSCs with increased expression of CYP1A1, GAD34, ATF4, NUPR1, CXCL12, KLF4, CCNB1 and nuclear localization of Dicer1. Interestingly, FA-MSCs did not show significant alterations in these genes upon Eto exposure. As opposed to healthy MSCs DICER1 gene expression and intracellular localization was not altered on FA BM-MSCs after Eto treatment. These results showed that Eto is a highly potent molecule and has pleiotropic effects on BM-MSCs, FA cells show altered expression profile compared to healthy controls and Eto exposure on FA cells shows differential profile than healthy controls.

A rare case of Klippel-Trenaunay syndrome presenting with chronic myeloid leukemia.

BACKGROUND: Klippel-Trenaunay syndrome (KTS) is an overgrowth syndrome associated with capillary/venous/ lymphatic malformations with limb hypertrophy and cancer risk. Various cancers, mostly Wilms tumor, have been reported in patients with KTS, but not leukemia. Chronic myeloid leukemia (CML) is also a rare disease in children, where there is no known disease or syndrome to predispose to CML. CASE: We report a case of CML incidentally diagnosed in a child with KTS when he was bleeding from surgery of the left groin for vascular malformation. CONCLUSIONS: This case reflects the variety of cancer types that may accompany KTS and provides information about CML prognosis in such patients.

Proteome alterations in erythrocytes with PIEZO1 gain-of-function mutations.

Gain-of-function mutations in PIEZO1 cause dehydrated hereditary stomatocytosis (DHS) or hereditary xerocytosis, an autosomal dominant hemolytic anemia characterized by high reticulocyte count, a tendency to macrocytosis, and mild jaundice, as well as by other variably penetrant clinical features, such as perinatal edema, severe thromboembolic complications after splenectomy, and hepatic iron overload. PIEZO1 mutations in DHS lead to slowed inactivation kinetics of the ion channel and/or facilitation of channel opening in response to physiological stimuli. To characterize the alterations of red blood cell proteome in patients with mutated PIEZO1, we used a differential approach to compare the proteome of patients with DHS (16 patients from 13 unrelated ancestries) vs healthy individuals. We identified new components in the regulation of the complex landscape of erythrocytes ion and volume balance mediated by PIEZO1. Specifically, the main impaired processes in patients with DHS were ion homeostasis, transmembrane transport, regulation of vesicle-mediated transport, and the proteasomal catabolic process. Functional assays demonstrated coexpression of PIEZO1 and band 3 when PIEZO1 was activated. Moreover, the alteration of the vesicle-mediated transport was functionally demonstrated by an increased vesiculation rate in patients with DHS compared with healthy controls. This finding also provides an explanation of the pathogenetic mechanism underlying the increased thrombotic rate observed in these patients. Finally, the newly identified proteins, involved in the intracellular signaling pathways altered by PIEZO1 mutations, could be used in the future as potential druggable targets in DHS.

Assessment of biochemical bone markers of osteoporosis in children with thalassemia major.

BACKGROUND: Beta thalassemia major (ß-TM) is a common cause of skeletal morbidity and is associated with increased bone fracture risk, particularly in inadequately transfused children. The aim of this study was to investigate some potential biochemical markers as possible early predictors of BMD variations in children with ß-TM. METHODS: The study included 38 children with ß-TM and 40 sex-age matched controls. All patients were subjected to BMD assessment by dual-energy X-ray absorptiometry (DEXA). Serum beta-crosslaps (beta-CTx), osteoprotegerin (OPG), receptor activator of nuclear factor-kappa B ligand (RANKL), urinary deoxypyridinoline (DPD) and ferritin levels were compared between the groups. RESULTS: Serum OPG levels were significantly lower in thalassemic children than in controls. The mean ratio of RANKL/OPG was significantly higher in the thalassemic patients than in the control group. Osteoporosis was detected in 10 (3 female and 7 male) of 38 patients (26.3%) according to the femur Z score and in 6 of them (4 male and 2 female) (15.8%) according to the spine Z score. CONCLUSIONS: Serum OPG concentrations can be used as a biochemical marker in screening patients with beta-thalassemia major for the development of osteoporosis.

HEATR3 variants impair nuclear import of uL18 (RPL5) and drive Diamond-Blackfan anemia.

The congenital bone marrow failure syndrome Diamond-Blackfan anemia (DBA) is typically associated with variants in ribosomal protein (RP) genes impairing erythroid cell development. Here we report multiple individuals with biallelic HEATR3 variants exhibiting bone marrow failure, short stature, facial and acromelic dysmorphic features, and intellectual disability. These variants destabilize a protein whose yeast homolog is known to synchronize the nuclear import of RPs uL5 (RPL11) and uL18 (RPL5), which are both critical for producing ribosomal subunits and for stabilizing the p53 tumor suppressor when ribosome biogenesis is compromised. Expression of HEATR3 variants or repression of HEATR3 expression in primary cells, cell lines of various origins, and yeast models impairs growth, differentiation, pre-ribosomal RNA processing, and ribosomal subunit formation reminiscent of DBA models of large subunit RP gene variants. Consistent with a role of HEATR3 in RP import, HEATR3-depleted cells or patient-derived fibroblasts display reduced nuclear accumulation of uL18. Hematopoietic progenitor cells expressing HEATR3 variants or small-hairpin RNAs knocking down HEATR3 synthesis reveal abnormal acceleration of erythrocyte maturation coupled to severe proliferation defects that are independent of p53 activation. Our study uncovers a new pathophysiological mechanism leading to DBA driven by biallelic HEATR3 variants and the destabilization of a nuclear import protein important for ribosome biogenesis.

A randomized, placebo-controlled, double-blind trial of canakinumab in children and young adults with sickle cell anemia.

Excessive intravascular release of lysed cellular contents from damaged red blood cells (RBCs) in patients with sickle cell anemia (SCA) can activate the inflammasome, a multiprotein oligomer promoting maturation and secretion of proinflammatory cytokines, including interleukin-1ß (IL-1ß). We hypothesized that IL-1ß blockade by canakinumab in patients with SCA would reduce markers of inflammation and clinical disease activity. In this randomized, double-blind, multicenter phase 2a study, patients aged 8 to 20 years with SCA (HbSS or HbSß0-thalassemia), history of acute pain episodes, and elevated high-sensitivity C-reactive protein >1.0 mg/L at screening were randomized 1:1 to received 6 monthly treatments with 300 mg subcutaneous canakinumab or placebo. Measured outcomes at baseline and weeks 4, 8, 12, 16, 20, and 24 included electronic patient-reported outcomes, hospitalization rate, and adverse events (AEs) and serious AEs (SAEs). All but 1 of the 49 enrolled patients were receiving stable background hydroxyurea therapy. Although the primary objective (prespecified reduction of pain) was not met, compared with patients in the placebo arm, patients treated with canakinumab had reductions in markers of inflammation, occurrence of SCA-related AEs and SAEs, and number and duration of hospitalizations as well as trends for improvement in pain intensity, fatigue, and absences from school or work. Post hoc analysis revealed treatment effects on weight, restricted to pediatric patients. Canakinumab was well tolerated with no treatment-related SAEs and no new safety signal. These findings demonstrate that the inflammation associated with SCA can be reduced by selective IL-1ß blockade by canakinumab with potential for therapeutic benefits. This trial was registered at www.clinicaltrials.gov as #NCT02961218.

Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency: Report on 30 Patients.

PURPOSE: Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-α) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2. METHODS: We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS). RESULTS: Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT. CONCLUSION: HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency. CLINICAL IMPLICATIONS: HCT is a definitive cure for DADA2 with > 95% survival.