Successful treatment of an infant with CDA type II by intrauterine transfusions and postnatal stem cell transplantation

The congenital dyserythropoieitic anemias: genetics and pathophysiology

PURPOSE OF REVIEW

The congenital dyserythropoietic anemias (CDA) are hereditary disorders characterized by ineffective erythropoiesis. This review evaluates newly developed CDA disease models, the latest advances in understanding the pathogenesis of the CDAs, and recently identified CDA genes.

RECENT FINDINGS

Mice exhibiting features of CDAI were recently generated, demonstrating that Codanin-1 (encoded by Cdan1) is essential for primitive erythropoiesis. Additionally, Codanin-1 was found to physically interact with CDIN1, suggesting that mutations in CDAN1 and CDIN1 result in CDAI via a common mechanism. Recent advances in CDAII (which results from SEC23B mutations) have also been made. SEC23B was found to functionally overlap with its paralogous protein, SEC23A, likely explaining the absence of CDAII in SEC23B-deficient mice. In contrast, mice with erythroid-specific deletion of 3 or 4 of the Sec23 alleles exhibited features of CDAII. Increased SEC23A expression rescued the CDAII erythroid defect, suggesting a novel therapeutic strategy for the disease. Additional recent advances included the identification of new CDA genes, RACGAP1 and VPS4A, in CDAIII and a syndromic CDA type, respectively.

SUMMARY

Establishing cellular and animal models of CDA is expected to result in improved understanding of the pathogenesis of these disorders, which may ultimately lead to the development of new therapies.

Hematopoietic Stem Cell Transplantation in Congenital Dyserythropetic Anemia Type II: A Case Report and Review of the Literature

Currently, there is no guideline for the treatment of patients with congenital dyserythropoietic anemia (CDA) type II. One approach is to follow-up patients with transfusions, on the basis of individually determined target hemoglobin levels, and iron chelation according to the thalassemia guidelines. In some transfusion-dependent CDA II patients, splenectomy reduces the number of transfusions; however, the only known curative option for CDA II patients is hematopoietic stem cell transplantation (HSCT). Only a few published case reports of allogeneic HSCT in CDA II patients are available. Here, we review the literature and add our data of a CDA II patient who developed transfusion dependence and was cured with HSCT.

Transfusion independence after repeated haploidentical hematopoietic cell transplants in a patient with congenital dyserythropoietic anemia type II and hemosiderosis

Matched related or unrelated donor allogeneic HCT has occasionally been applied in patients with severe CDA type II and proven to be curative. We report on the first patient with CDA to undergo haploidentical bone marrow transplantation with PT-CY. A 12-year-old boy with severe hemosiderosis, and a, consequently, disturbed BM microenvironment, developed recurrent graft failures and required salvage with two additional haploidentical HCTs. He achieved complete donor chimerism and transfusion independence after the third HCT. Our case underscores the risks associated with performing haploidentical HCT in older pediatric patients with CDA and severe chronic iron overload.

[New mutation site of SEC23B gene in type Ⅱ congenital erythrocythememia anemia: one case report and literatures review]

Objective: To enrich the gene mutation sites and accumulate treatment experience of congenital dyserythropoietic anemia (CDA) type Ⅱ by reporting one case of CDA patient with new mutation site of SEC23B and was successfully treated by homozygous allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: The mutation within SEC23B gene in a child case with the reduced hemoglobin for more than 3 months, and his family were analyzed in combination with literatures review. Results: A 3-day 5-month female child was admitted due to "decreasing hemoglobin for more than 3 months" , blood routine test showed HGB 44 g/L, positive for acid hemolysis test (Ham test) . Bone marrow showed that the proportion of erythroid line was 69%, mainly middle and late juvenile erythrocytes, binuclear and odd nucleated erythrocytes could be observed, and nuclear fragmentation and nuclear budding could be seen occasionally in nucleated erythrocytes, transmission electron microscopy disclosed that bone marrow harbored the typical double-layer membrane structure of nuclear erythrocytes. There were two unreported new mutation sites in the SEC23B gene, including 1504 G>C/wt and c. 2254-2255 insert A/wt. The two mutations were derived from the father and mother of the child respectively. At the late stage, the child was successfully treated with allo-HSCT, the original mutation turned negative. Conclusion: This study reported the mutation type of SEC23B gene insertion for the first time in China. Allo-HSCT could be utilized as a treatment for CDA.

Clinical and genetic features of congenital dyserythropoietic anemia (CDA)

INTRODUCTION

Congenital dyserythropoietic anemias (CDA) are characterized by hyporegenerative anemia with inadequate reticulocyte values, ineffective erythropoiesis, and hemolysis. Distinctive morphology of bone marrow erythroblasts and identification of causative genes allow classification into 4 types caused by variants in CDAN1, c15orf41, SEC23B, KIF23, and KLF1 genes.

OBJECTIVE

Identify pathogenic variants in CDA patients.

METHODS

Massive parallel sequencing with a targeted gene panel, Sanger sequencing, Comparative Genome Hybridization (CGH), and in silico predictive analysis of pathogenicity.

RESULTS

Pathogenic variants were found in 21 of 53 patients studied from 44 unrelated families. Six variants were found in CDAN1: two reported, p.Arg714Trp and p.Arg725Trp and, four novel, p.Arg623Trp, p.Arg946Trp, p.Phe1125Ser and p.Ser1227Gly. Twelve variants were found in SEC23B: seven reported, p.Arg14Trp, p.Glu109Lys, p.Arg217Ter, c.835-2A>G, p.Arg535Ter, p.Arg550Ter and p.Arg718Ter and, five novel, p.Val164Leu, p.Arg190Gln, p.Gln521Ter, p.Arg546Trp, and p.Arg611Gln. The variant p.Glu325Lys in KLF1 was found in one patient and p.Tyr365Cys in ALAS2 in an other. Moreover, we identified genomic rearrangements by CGH in some SEC23B-monoallelic patients.

CONCLUSIONS

New technologies for genetic studies will help to find variants in other genes, in addition to those known, that contribute to or modulate the CDA phenotype or support the correct diagnosis.

Successful Allogeneic Hematopoietic Stem Cell Transplantation of a Patient Suffering from Type II Congenital Dyserythropoietic Anemia A Rare Case Report from Western India

The most frequent form of congenital dyserythropoiesis (CDA) is congenital dyserythropoietic anemia II (CDA II). CDA II is a rare genetic anemia in humans, inherited in an autosomally recessive mode, characterized by hepatosplenomegaly normocytic anemia and hemolytic jaundice. Patients are usually transfusion-independent except in severe type. We are here reporting a case of severe transfusion-dependent type II congenital dyserythropoietic anemia in a 5-year-old patient who has undergone allogeneic hematopoietic stem cell transplantation (HSCT) at our bone marrow transplantation centre. Patient has had up until now more than 14 mL/kg/month of packed cell volume (PCV), which he required every 15 to 20 days to maintain his hemoglobin of 10 gm/dL and hematocrit of 30%. His pre-HSCT serum ferritin was 1500 ng/mL and he was on iron chelating therapy. Donor was HLA identical sibling (younger brother). The preparative regimen used was busulfan, cyclophosphamide, and antithymocyte globulin (Thymoglobulin). Cyclosporine and short-term methotrexate were used for graft versus host disease (GVHD) prophylaxis. Engraftment of donor cells was quick and the posttransplant course was uneventful. The patient is presently alive and doing well and he has been transfusion-independent for the past 33 months after HSCT.

Retrospective cohort study of 205 cases with congenital dyserythropoietic anemia type II: definition of clinical and molecular spectrum and identification of new diagnostic scores

Congenital Dyserythropoietic Anemia II (CDA II) is a rare hyporegenerative anemia of variable degree, whose causative gene is SEC23B. More than 60 causative mutations in 142 independent pedigrees have been described so far. However, the prevalence of the CDA II is probably underestimated, since its clinical spectrum was not yet well-defined and thus it is often misdiagnosed with more frequent clinically-related anemias. This study represents the first meta-analysis on clinical and molecular spectrum of CDA II from the largest cohort of cases ever described. We characterized 41 new cases and 18 mutations not yet associated to CDA II, thus expanding the global series to 205 cases (172 unrelated) and the total number of causative variants to 84. The 68.3% of patients are included in our International Registry of CDA II (Napoli, Italy). A genotype-phenotype correlation in three genotypic groups of patients was assessed. To quantify the degree of severity in each patient, a method based on ranking score was performed. We introduced a clinical index to easily discriminate patients with a well-compensated hemolytic anemia from those with ineffective erythropoiesis. Finally, the worldwide geographical distribution of SEC23B alleles highlighted the presence of multiple founder effects in different areas of the world.

Successful hematopoietic stem cell transplantation in a patient with congenital dyserythropoietic anemia type II

CDA are a group of inherited, rare diseases that are characterized by dyserythropoiesis and ineffective erythropoiesis associated with transfusion dependency in approximately 10% of cases. For these latter patients, the only curative treatment is HSCT. There are very limited data on HSCT experience in this rare disease. Herein, we report a five-yr six-month-old girl with compound heterozygous mutations in SEC23B gene, who was diagnosed to have CDA type II and underwent successful HSCT from her matched sibling donor.