Comprehensive Genomic Analysis Identifies a Diverse Landscape of Sideroblastic and Nonsideroblastic Iron-Related Anemias with Novel and Pathogenic Variants in an Iron-Deficient Endemic Setting.

Inherited iron metabolism defects are possibly missed or underdiagnosed in iron-deficient endemic settings because of a lack of awareness or a methodical screening approach. Hence, we systematically evaluated anemia cases (2019 to 2021) based on clinical phenotype, normal screening tests (high-performance liquid chromatography, α gene sequencing, erythrocyte sedimentation rate, C-reactive protein, and tissue transglutaminase), and abnormal iron profile by targeted next-generation sequencing (26-gene panel) supplemented with whole-exome sequencing, multiplex ligation probe amplification/mitochondrial DNA sequencing, and chromosomal microarray. Novel variants in ALAS2, STEAP3, and HSPA9 genes were functionally validated. A total of 290 anemia cases were screened, and 41 (14%) enrolled for genomic testing as per inclusion criteria. Comprehensive genomic testing revealed pathogenic variants in 23 of 41 cases (56%). Congenital sideroblastic anemia was the most common diagnosis (14/23; 61%), with pathogenic variations in ALAS2 (n = 6), SLC25A38 (n = 3), HSPA9 (n = 2) and HSCB, SLC19A2, and mitochondrial DNA deletion (n = 1 each). Nonsideroblastic iron defects included STEAP3-related microcytic anemia (2/23; 8.7%) and hypotransferrenemia (1/23; 4.3%). A total of 6 of 22 cases (27%) revealed a non-iron metabolism gene defect on whole-exome sequencing. Eleven novel variants (including variants of uncertain significance) were noted in 13 cases. Genotype-phenotype correlation revealed a significant association of frameshift/nonsense/splice variants with lower presentation age (0.8 months versus 9 years; P < 0.01) compared with missense variants. The systematic evaluation helped uncover an inherited iron defect in 41% (17/41) of cases, suggesting the need for active screening and awareness for these rare diseases in an iron-deficient endemic population.

Spontaneous, simultaneous bilateral osteonecrosis of the femoral heads in a patient with sideroblastic anaemia with B-cell immunodeficiency, periodic fever and developmental delay syndrome.

Sideroblastic anaemia with B-cell immunodeficiency, periodic fever and developmental delay is a recently described, rare syndrome characterised by numerous manifestations underpinned by mutations in transfer RNA nucleotidyltransferase. The pathogenesis arises from mitochondrial dysfunction, with impaired intracellular stress response, deficient metabolism and cellular and systemic inflammation. This yields multiorgan dysfunction and early death in many patients with survivors suffering significant disability and morbidity. New cases, often youths, are still being described, expanding the horizon of recognisable phenotypes. We present a mature patient with spontaneous bilateral hip osteonecrosis that likely arises from the impaired RNA quality control and inflammation caused by this syndrome.

Three siblings with variable degrees of neuromuscular involvement and congenital sideroblastic anemia: A peculiar phenotype and a surprise genotypic explanation.

INTRODUCTION: Congenital sideroblastic anemias (CSAs) are a group of inherited bone-marrow disorders manifesting with erythroid hyperplasia and ineffective erythropoiesis. METHODS: We describe a detailed clinical and genetic characterization of three siblings with CSA. RESULTS: Two of them had limb-girdle myopathy and global developmental delay. The two elder siblings performed allogenic hematopoietic stem-cell transplantation 5 and 3 years prior with stabilization of the hematological features. Exome sequencing in the non-transplanted sibling revealed a novel homozygous nonsense variant in SLC25A38 gene NM_017875.2:c.559C > T; p.(Arg187*) causing autosomal-recessive sideroblastic anemia type-2, and a second homozygous pathogenic previously reported variant in GMPPB gene NM_013334.3:c.458C > T; p.(Thr153Ile) causing autosomal-recessive muscular dystrophy-dystroglycanopathy type B14. With the established diagnosis, hematopoietic stem cell transplantation is now being scheduled for the youngest sibling, and a trial therapy with acetylcholine esterase inhibitors was started for the two neurologically affected patients with partial clinical improvement. CONCLUSION: This family emphasizes the importance of whole-exome sequencing for familial cases with complex phenotypes and vague neurological manifestations.

Allogenic Hematopoietic Stem Cell Transplant in Iranian Patients With Congenital Sideroblastic Anemia: A Single-Center Experience.

Congenital sideroblastic anemia is characterized by anemia and intramitochondrial iron accumulation in erythroid precursors that form ring sideroblasts. The most common recessive forms are caused by sequence variations in the ALAS2 and SLC25A38 genes. In patients with transfusion-dependent and pyridoxine- resistant severe congenital sideroblastic anemia, hematopoietic stem celltransplantis the only curative option. Herein, we described successful implementations of allogeneic hematopoietic stem cell transplant in 4 Iranian children with congenital sideroblastic anemia. The patients had presented with clinical manifestations of anemia early in life, and the diagnoses of congenital sideroblastic anemia were established through blood tests and bone marrow aspiration. Congenital sideroblastic anemia was further confirmed by the identification of pathogenic variants in SLC25A38 in 2 patients. All 4 patients received allogeneic hematopoietic stem cell transplant with myeloablative conditioning regimen that included busulfan, cyclophosphamide, andrabbit antithymocyte globulin. A combination of cyclosporine A and methotrexate or mycophenolate mofetil was used for graft-versus-host disease prophylaxis. Bone marrow and peripheral blood from sibling or related donors with fully matched human leukocyte antigen profiles were applied. The outcomes of hematopoietic stem celltransplantin patients with congenital sideroblastic anemia were favorable. Three patients achieved full donor chimerism (>95%, 98%, and 100%), and the other patient showed mixed chimerism (75%). All patients remained transfusion independent. Hemato- poietic stem celltransplantis a curative treatmentthat can provide long-term survival for patients with congenital sideroblastic anemia, particularly when used in a timely manner. There remain ongoing challenges in various aspects of hematopoietic stem celltransplantin patients with congenital sideroblastic anemia, which remain to be elucidated.

Thalidomide as an Effective Treatment in Sideroblastic Anemia, Immunodeficiency, Periodic Fevers, and Developmental Delay (SIFD).

PURPOSE: Sideroblastic anemia, immunodeficiency, periodic fevers, and developmental delay (SIFD) is an autosomal recessive syndrome caused by biallelic loss-of-function variant of tRNA nucleotidyl transferase 1 (TRNT1). Efficacious methods to treat SIFD are lacking. We identified two novel mutations in TRNT1 and an efficacious and novel therapy for SIFD. METHODS: We retrospectively summarized the clinical records of two patients with SIFD from different families and reviewed all published cases of SIFD. RESULTS: Both patients had periodic fever, developmental delay, rash, microcytic anemia, and B cell lymphopenia with infections. Whole-exome sequencing of patient 1 identified a previously unreported homozygous mutation of TRNT1 (c.706G > A/p.Glu236Lys). He received intravenous immunoglobulin (IVIG) replacement and antibiotics, but died at 1 year of age. Gene testing in patient 2 revealed compound heterozygous mutations (c.907C > G/p.Gln303Glu and c.88A > G/p.Met30Val) in TRNT1, the former of which is a novel mutation. Periodic fever was controlled in the first month after adalimumab therapy and IVIG replacement, but recurred in the second month. Adalimumab was discontinued and replaced with thalidomide, which controlled the periodic fever and normalized inflammatory markers effectively. A retrospective analysis of reported cases revealed 69 patients with SIFD carrying 46 mutations. The male: female ratio was 1: 1, and the mean age of onset was 3.0 months. The most common clinical manifestations in patients with SIFD were microcytic anemia (82.6%), hypogammaglobulinemia/B cell lymphopenia (75.4%), periodic fever (66.7%), and developmental delay (60.0%). In addition to the typical tetralogy, SIFD features several heterogeneous symptoms involving multiple systems. Corticosteroids, immunosuppressants, and anakinra have low efficacy, whereas etanercept suppressed fever and improved anemia in reports. Bone-marrow transplantation can be used to treat severe SIFD, but carries a high risk. In total, 28.2% (20/71) of reported patients died, mainly because of multi-organ failure. Biallelic mutations located in exon1-intron5 lead to more severe phenotypes and higher mortality. Furthermore, 15.5% (11/71) patients survived to adulthood. The symptoms could be resolved spontaneously in five patients. CONCLUSIONS: Thalidomide can control the inflammation of SIFD and represents a new treatment for SIFD.

Clinical and Therapeutic Aspects of Sideroblastic Anaemia with B-Cell Immunodeficiency, Periodic Fever and Developmental Delay (SIFD) Syndrome: a Systematic Review.

BACKGROUND AND PURPOSE: Sideroblastic anaemia with B-cell immunodeficiency, periodic fever and developmental delay (SIFD) syndrome is a novel rare autoinflammatory multisystem disorder. We performed a systematic review of the available clinical and therapeutics aspects of the SIFD syndrome. METHODS: A systematic review according to PRISMA approach, including all articles published before the 30th of July 2021 in Pubmed and EMBASE database, was performed. RESULTS: The search identified 29 publications describing 58 unique patients. To date, 41 unique mutations have been reported. Onset of disease is very early with a median age of 4 months (range 0-252 months). The most frequent manifestations are haematologic such as microcytic anaemia or sideroblastic anaemia (55/58), recurrent fever (52/58), neurologic abnormalities (48/58), immunologic abnormalities in particular a humoral immunodeficiency (48/58), gastrointestinal signs and symptoms (38/58), eye diseases as cataract and retinitis pigmentosa (27/58), failure to thrive (26/58), mucocutaneous involvement (29/58), sensorineural deafness (19/58) and others. To date, 19 patients (35.85%) died because of disease course (16) and complications of hematopoietic cell stems transplantation (3). The use of anti-TNFα and hematopoietic cell stems transplantation (HCST) is dramatically changing the natural history of this disease. CONCLUSIONS: SIFD syndrome is a novel entity to consider in a child presenting with recurrent fever, anaemia, B-cell immunodeficiency and neurodevelopmental delay. To date, therapeutic guidelines are lacking but anti-TNFα treatment and/or HCST are attractive and might modify the clinical course of this syndrome.

Decompensation of cardiorespiratory function and emergence of anemia during pregnancy in a case of mitochondrial myopathy, lactic acidosis, and sideroblastic anemia 2 with compound heterozygous YARS2 pathogenic variants.

Myopathy, lactic acidosis, and sideroblastic anemia 2 (MLASA2) is an autosomal recessive mitochondrial disorder caused by pathogenic variants in YARS2. YARS2 variants confer heterogeneous phenotypes ranging from the full MLASA syndrome to a clinically unaffected state. Symptom onset is most common in the first decade of life but can occur in adulthood and has been reported following intercurrent illness. Early death can result from respiratory muscle weakness and cardiomyopathy. We report a case of MLASA2 with compound heterozygous YARS2 pathogenic variants; a known pathogenic nonsense variant [NM_001040436.3:c.98C>A (p.Ser33Ter)] and a likely pathogenic missense variant not previously associated with disease [NM_001040436.3:c.948G>T (p.Arg316Ser)]. The proband initially presented with a relatively mild phenotype of myopathy and lactic acidosis. During pregnancy, anemia emerged as an additional feature and in the postpartum period she experienced severe decompensation of cardiorespiratory function. This is the first reported case of pregnancy-related complications in a patient with YARS2-related mitochondrial disease. This case highlights the need for caution and careful counseling when considering pregnancy in mitochondrial disease, due to the risk of disease exacerbation and pregnancy complications.

Clinical Application for Diagnosis of Myelodysplatic/Myeloproliferative Neoplasm with Ring Sideroblasts and Thrombocytosis.

BACKGROUND: Myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/ MPN-RS-T) was newly introduced as a full entity in the 2016 revision of the WHO classification. In this study, we investigated the morphologic, laboratory, and clinical features of MDS/MPN-RS-T. METHODS: We reviewed the bone marrow and genetic studies of patients whose diagnoses were coded as "refractory anemia with ring sideroblasts (RARS)" or "MDS/MPN, unclassifiable" between January 2008 and April 2018. RESULTS: A total of 8 cases fulfilled the criteria for a diagnosis of MDS/MPN-RS-T. All of them had no specific symptoms. Half of the cases had less than 450 × 109/L platelet counts by an automated hematology analyzer; however, all platelet counts exceeded 450 × 109/L when performed manually. JAK2 mutation tests were performed in 7 cases, and a heterozygous mutation was detected in 1 case. SF3B1 mutations were present in 3 of the 4 cases tested. CONCLUSIONS: When RARS is suspected in patients without thrombocytopenia, manual platelet counts should be performed. For patients with suspected essential thrombocythemia, RS evaluation through careful observation of an iron-stained slide is crucial. Since the independent evaluation of RS was reflected in the revised classification, the ambiguous disease classification becomes clearer and more consistent.

Sideroblastic anaemia in a patient with sickle cell disease.

Sideroblastic anaemia is a rare condition. We report a unique case of concomitant sideroblastic anaemia in a patient with sickle cell disease with long-standing blood transfusion history. Due to a low prevalence of sideroblastic anaemia, the diagnosis of sideroblastic anaemia is often difficult, especially when coexisting with common types of anaemia, including sickle cell disease. This case highlights the detrimental effects of anchoring bias. Rare causes of refractory anaemia should be considered in patients with haemoglobin disorders as the therapeutic approaches for these conditions are different. High suspicion on the part of the clinician and low threshold for workup of anaemia often aids in the diagnosis of coexisting conditions such as sideroblastic anaemia. Early diagnosis and treatment of sideroblastic anaemia improves patient outcomes and prevents long-term complications.

Bone marrow ring sideroblasts in hematological diseases: an analysis of consecutive 1300 samples in a single institution.

The incidence of MDS-RS in Japan has been recognized as about 5% which is lower than that in European countries. Insufficient use of iron staining tests in Japan has been noted as one conceivable factor contributing to this apparently lower prevalence. To investigate this issue, we analyzed the proportion of ring sideroblasts (RS) in 1300 bone marrow samples from patients with hematological diseases at Kitasato University Hospital, including iron staining of all samples. Sixteen of 96 patients with MDS (16.7%) were diagnosed with MDS-RS, and this accounted for 26.2% of MDS without excess blasts. Some MDS-EB (22.9%) and AML-MRC (13.8%) patients also had ≥ 15% RS. In contrast, RS were rarely found in myeloid neoplasms without dysplasia and non-myeloid diseases: only 1 in 46 (2.2%) patients with AML without dysplasia, 2 in 93 (2.2%) with MPN, and 8 in 984 (0.8%) with non-myeloid diseases had ≥ 5% RS. These results indicate that prevalence of MDS-RS in Japan may be higher than conventionally recognized and that RS are principally restricted to myelodysplastic disorders. Further multicenter studies using consecutive bone marrow samples with iron staining tests will be required to confirm our findings.

Treatment outcomes for patients with myelodysplastic syndrome/myeloproliferative neoplasms with ring sideroblasts and thrombocytosis.

Myelodysplastic syndrome/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T) is characterized by anemia, ring sideroblast erythroid precursors, and persistent thrombocytosis. Case reports suggest lenalidomide may be effective in treating MDS/MPN-RS-T. We evaluated a large series of patients with MDS/MPN-RS-T to compare hematological improvement (HI) response rates among different drug therapies including lenalidomide. We identified 167 patients with MDS/MPN-RS-T. Among the patients tested, 84% had SF3B1 mutations and 43% had JAK2 V617F mutations. The median OS for the cohort was 81 months. Overall, 76 patients (46%) received erythropoiesis-stimulating agents (ESAs), 47 patients (28%) received lenalidomide, and 45 patients (27%) received hypomethylating agents (HMAs). The HI rates were 58%, 53%, and 24%, respectively. The median duration of treatment was 11 months for lenalidomide compared to 6 months for HMAs. Rates of HI improvement were higher in patients with MDS/MPN-RS-T treated with ESAs or lenalidomide, in comparison to those treated with HMAs.

Differentiating iron-loading anemias using a newly developed and analytically validated ELISA for human serum erythroferrone.

Erythroferrone (ERFE), the erythroid regulator of iron metabolism, inhibits hepcidin to increase iron availability for erythropoiesis. ERFE plays a pathological role during ineffective erythropoiesis as occurs in X-linked sideroblastic anemia (XLSA) and ß-thalassemia. Its measurement might serve as an indicator of severity for these diseases. However, for reliable quantification of ERFE analytical characterization is indispensable to determine the assay's limitations and define proper methodology. We developed a sandwich ELISA for human serum ERFE using polyclonal antibodies and report its extensive analytical validation. This new assay showed, for the first time, the differentiation of XLSA and ß-thalassemia major patients from healthy controls (p = 0.03) and from each other (p<0.01), showing the assay provides biological plausible results. Despite poor dilution linearity, parallelism and recovery in patient serum matrix, which indicated presence of a matrix effect and/or different immunoreactivity of the antibodies to the recombinant standard and the endogenous analyte, our assay correlated well with two other existing ERFE ELISAs (both R2 = 0.83). Nevertheless, employment of one optimal dilution of all serum samples is warranted to obtain reliable results. When adequately performed, the assay can be used to further unravel the human erythropoiesis-hepcidin-iron axis in various disorders and assess the added diagnostic value of ERFE.

Two cases of sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay (SIFD) syndrome in Chinese Han children caused by novel compound heterozygous variants of the TRNT1 gene.

Sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay (SIFD) syndrome is a serious autosomal recessive genetic disease. So far, <40 cases have been reported worldwide, and only one case has been reported in China. The main clinical features of SIFD are sideroblastic or microcytic anemia, immune deficiency, and recurrent episodes of inflammation. Here, we describe two unrelated cases of SIFD from China with different clinical manifestations and mild symptoms. Patient 1 was hospitalized at the age of 3.5 years due to persistent joint swelling with imaging of multiple joint effusions. Patient 2 was hospitalized at the age of 12 years due to repeated rashes on both lower limbs and oral ulcers. SIFD was detected using gene testing, which revealed the following compound heterozygous variants in TRNT1 in cases 1 and 2, respectively: c.88A > G/c.363G > T and c.302 T > C/c.1234cC > T. Searches of the HGMD databases revealed that these variants were all novel. Molecular dynamics simulations revealed that the missense variants c.363G > T and c.302 T > C would cause changes in protein structure and thus affect protein function. Finally, through literature reviewing, we found that the mortality in cases of SIFD was approximately 44% (14/32), and about 79% of individuals who died carried the hot-spot mutation c.668 T > C. Moreover, variants in the non-coding region were significantly more common among patients who died than among survivors. Our cases further expand the existing knowledge of the phenotype and variation spectrums of SIFD and suggest that genomic diagnosis is valuable for the hierarchical clinical management of this disease.

Case Report: Expanding Clinical, Immunological and Genetic Findings in Sideroblastic Anemia With Immunodeficiency, Fevers and Development Delay (SIFD) Syndrome.

Since the first description of the syndrome of sideroblastic anemia with immunodeficiency, fevers and development delay (SIFD), clinical pictures lacking both neurological and hematological manifestations have been reported. Moreover, prominent skin involvement, such as with relapsing erythema nodosum, is not a common finding. Up to this moment, no genotype and phenotype correlation could be done, but mild phenotypes seem to be located in the N or C part. B-cell deficiency is a hallmark of SIFD syndrome, and multiple others immunological defects have been reported, but not high levels of double negative T cells. Here we report a Brazilian patient with a novel phenotype of SFID syndrome, carrying multiple immune defects and harboring a novel mutation on TRNT1 gene.

[Rare sideroblastic anemias: about 2 cases, review of the literature and reminder of the main etiologies]. / Anémies sidéroblastiques rares : à propos de 2 cas, revue de la littérature et rappel des principales étiologies.

Sideroblastic anemias in adults are often quickly labeled as myelodysplasias. We report two unfrequent observations of secondary acquired forms. The first one is a 15-year-old girl presented with severe cytopenias. The myelogram revealed the presence of vacuolated myeloid and erythroblastic precursors, with ring sideroblasts. Copper deficiency has been demonstrated in front of the association with collapsed cupremia and ceruleoplasminemia, with normal cupruria. The second case is a 70-year-old man, treated for 1 month with several lines of antibiotics for a skin infection, referred for cytopenias. The myelogram found vacuolated erythroblastic precursors and ring sideroblasts. Linezolid's responsibility has been proposed, with a favorable development after treatment has been stopped. These two observations, which describe unfrequent sideroblastic anemias, point out that this discovery should not lead to the diagnosis of myelodysplasia before having considered the many other etiologies.

Myelodysplastic syndromes with ring sideroblasts (MDS-RS) and MDS/myeloproliferative neoplasm with RS and thrombocytosis (MDS/MPN-RS-T) - "2021 update on diagnosis, risk-stratification, and management".

DISEASE OVERVIEW: Ring sideroblasts (RS) are erythroid precursors with abnormal perinuclear mitochondrial iron accumulation. Two myeloid neoplasms defined by the presence of RS, include myelodysplastic syndromes with RS (MDS-RS) and MDS/myeloproliferative neoplasm with RS and thrombocytosis (MDS/MPN-RS-T). DIAGNOSIS: MDS-RS is a lower risk MDS, with single or multilineage dysplasia (MDS-RS-SLD/MLD), <5% bone marrow (BM) blasts, <1% peripheral blood blasts and ≥15% BM RS (≥5% in the presence of SF3B1 mutations). MDS/MPN-RS-T, now a formal entity in the MDS/MPN overlap syndromes, has diagnostic features of MDS-RS-SLD, along with a platelet count ≥450 × 109 /L and large atypical megakaryocytes. MUTATIONS AND KARYOTYPE: Mutations in SF3B1 are seen in ≥80% of patients with MDS-RS-SLD and MDS/MPN-RS-T, and strongly correlate with the presence of BM RS; MDS/MPN-RS-T patients also demonstrate JAK2V617F (50%), DNMT3A, TET2 and ASXL1 mutations. Cytogenetic abnormalities are uncommon in both. RISK STRATIFICATION: Most patients with MDS-RS-SLD are stratified into lower risk groups by the revised-IPSS. Disease outcome in MDS/MPN-RS-T is better than that of MDS-RS-SLD, but worse than that of essential thrombocythemia (MPN). Both diseases are associated with a low risk of leukemic transformation. TREATMENT: Anemia and iron overload are complications seen in both and are managed similar to lower risk MDS and MPN. Luspatercept, a first-in-class erythroid maturation agent is now approved for the management of anemia in patients with MDS-RS and MDS/MPN-RS-T. Aspirin therapy is reasonable in MDS/MPN-RS-T, especially in the presence of JAK2V617F, but the value of platelet-lowering drugs remains to be defined.