Congenital sideroblastic anaemia successfully treated using allogeneic stem cell transplantation

Case report: An infant boy with X-linked sideroblastic anaemia successfully treated by umbilical cord blood haematopoietic stem cell transplantation

X-linked sideroblastic anaemia (XLSA) is an inherited disorder caused by mutations in genes encoding proteins involved in the biosynthesis of haem. The pathogenic gene, as well as the pathogenesis and diagnosis of XLSA, have been fully elucidated in previous studies. However, only a few new advances have been made in managing XLSA in recent years, and blood transfusion remains the primary treatment. We report a case of umbilical cord blood haematopoietic stem cell transplantation in a male infant diagnosed with XLSA who was born with asphyxia due to severe anaemia. Early hepatic vein occlusion occurred after transplantation. However, this complication was rapidly controlled after active treatment, and the child’s quality of life improved significantly. Haematopoietic stem cell transplantation is a promising alternative treatment for XLSA.

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.

Clinical characterization and hematopoietic stem cell transplant outcomes for congenital sideroblastic anemia caused by a novel pathogenic variant in SLC25A38

BACKGROUND

Congenital sideroblastic anemia (CSA) constitutes an uncommon category of inherited anemia often associated with pathologic iron accumulation. Pathogenic variants in several genes have been identified as causative for CSA. Autosomal recessive pathogenic variants in the mitochondrial glycine transporter SLC25A38 have been implicated in a subset of patients with CSA.

PROCEDURE

We describe seven individuals of Canadian Cree descent with a known or inferred homozygous novel founder missense variant in SLC25A38 (c.560G>A, p.Arg187Gln).

RESULTS

All individuals presented as young children (median age 6 months) with severe microcytic, hypochromic anemia associated with pretransfusion iron overload, requiring red cell transfusion support and iron chelation. Six individuals received pyridoxine supplementation; two demonstrating transient partial responses. Three individuals underwent allogeneic hematopoietic stem cell transplantation (HSCT). One individual with significant iron loading died in the posttransplant period due to complications of sepsis. The other two individuals remain transfusion-free following HSCT.

CONCLUSIONS

Despite a common genetic etiology, phenotypic variability was noted in this cohort. A transient response to pyridoxine was noted in two individuals but should not be considered a long-term therapeutic strategy. HSCT was curative when performed before significant iron loading occurred. Early identification of CSA and timely HSCT can result in excellent long-term outcomes.

Graft failure after reduced-intensity stem cell transplantation for congenital sideroblastic anemia

Congenital sideroblastic anemia (CSA) is a rare hereditary disease causing disorders of hemoglobin synthesis. Severe, progressive congenital sideroblastic anemia becomes transfusion dependent and results in iron overload. In such cases, patients must undergo stem cell transplantation (SCT) before critical organ dysfunction occurs. However, there has been no consensus on the criteria for SCT for congenital sideroblastic anemia. A 17-year-old Japanese boy was newly diagnosed with congenital sideroblastic anemia manifesting dyspnea on effort. His gene analysis revealed ALAS2 R170L. He gradually become dependent on RBC transfusion. Vitamin B6 (pyridoxal, 30 mg/day) therapy and high-dose alpha-linoleic acid supplementation (150 mg/day) had not been effective. We treated the patient with reduced-intensity SCT from a human leukocyte antigen (HLA) alle 8/8-identical unrelated female donor. The preparation regimen applied consisted of cyclophosphamide, fludarabine, total body irradiation (2 Gy), and anti-thymocyte globulin. We experienced secondary graft failure, nevertheless we used enough immunosuppression. Here we discuss the optimal transplantation regimen for an adult-onset congenital sideroblastic anemia patient with transfusion dependency and mild hemosiderosis. We consider a positive indication for SCT in younger (< 20-year-old) patients with congenital sideroblastic anemia with transfusion dependency. Each case should be individually considered for their suitability for SCT depending on the feasibility and the clinical condition of the patient.

Reduced-toxicity allogeneic hematopoietic stem cell transplantation in congenital sideroblastic anemia

The case of an infant girl with severe congenital sideroblastic anemia associated with a novel molecular defect in mitochondrial transporter SLC25A38 is presented. Her transfusion dependence was fully reversed following allogeneic hematopoietic stem cell transplantation using a modified reduced-intensity conditioning regimen, and she remains healthy 5 years posttransplant.

Transfusion-dependent congenital dyserythropoietic anemia type I successfully treated with allogeneic stem cell transplantation

Until recently, therapy for patients with severe congenital dyserythropoietic anemia (CDA) has been limited to blood transfusions and chelation therapy. Three children with transfusion-dependent CDA type I underwent allogeneic stem cell transplantation (SCT) from matched sibling donors. Conditioning was with cyclophosphamide 50 mg/kg/day for 4 days, busulphan 4 mg/kg/day for 4 days, and antithymocyte globulin (ATG) 30 mg/kg for four doses pre-SCT. All patients engrafted and are alive, and transfusion independent. To our knowledge, this is the first report of successful SCT in the management of CDA type I.