Congenital dyserythropoietic anemia type I: First report from the Congenital Dyserythropoietic Anemia Registry of North America (CDAR).

Congenital dyserythropoietic anemias (CDAs) are characterized by ineffective erythropoiesis and distinctive erythroblast abnormalities; the diagnosis is often missed or delayed due to significant phenotypic heterogeneity. We established the CDA Registry of North America (CDAR) to study the natural history of CDA and create a biorepository to investigate the pathobiology of this heterogeneous disease. Seven of 47 patients enrolled so far in CDAR have CDA-I due to biallelic CDAN1 mutations. They all presented with perinatal anemia and required transfusions during infancy. Anemia spontaneously improved during infancy in three patients; two became transfusion-independent rapidly after starting interferon-α2; and two remain transfusion-dependent at last follow-up at ages 5 and 30 y.o. One of the transfusion-dependent patients underwent splenectomy at 11 y.o due to misdiagnosis and returned to medical attention at 27 y.o with severe hemolytic anemia and pulmonary hypertension. All patients developed iron overload even without transfusions; four were treated with chelation. Genetic testing allowed for more rapid and accurate diagnosis; the median age of confirmed diagnosis in our cohort was 3 y.o compared to 17.3 y.o historically. In conclusion, CDAR provides an organized research network for multidisciplinary clinical and research collaboration to conduct natural history and biologic studies in CDA.

Fetal presentation of congenital dyserythropoietic anemia type 1 with novel compound heterozygous CDAN1 mutations.

The congenital dyserythropoietic anemias are a heterogeneous group of disorders characterized by anemia and ineffective erythropoiesis. Congenital dyserythropoietic anemia type I (CDA1) can present in utero with hydrops fetalis, but more often it presents in childhood or adulthood with moderate macrocytic anemia, jaundice, and progressive iron-overload. CDA1 is inherited in an autosomal recessive manner, with biallelic pathogenic variants in CDAN1 or C15orf41. This case report documents a severe fetal presentation of CDA1 where we identified two novel compound heterozygous mutations in CDAN1 and describes the associated pathologic findings and levels of iron-regulatory proteins hepcidin, erythroferrone, and GDF15.

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.

Morphological features of congenital dyserythropoietic anemia type I: The role of electron microscopy in diagnosis.

INTRODUCTION: Congenital dyserythropoietic anemias are rare blood disorders characterized by congenital anemia and a wide range of morphological and functional abnormalities of erythroid precursors. OBJECTIVES: To analyze the relative frequency of both light microscopic (LM) and electron microscopic (EM) morphological features of erythroblasts in a large group of patients with molecular proven congenital dyserythropoietic anemia type I (CDAI). METHODS: We retrospectively evaluated the LM and EM of bone marrow (BM) erythroblasts in 35 patients with CDAI. Thirty-four patients carried the CDAN1 Arg1042Trp founder mutation and one the p.Pro1130Leu mutation. BM slides of 24 patients were available for LM examination. EM studies were performed in all 35 patients. RESULTS: On LM, marked erythroid hyperplasia, binuclear erythroblasts, and various non-specific dyserythropoietic features were documented in every case; internuclear chromatin bridges were detected in 19 patients (79%). In all, EM of erythroblasts revealed a spongy appearance of heterochromatin, a widening of nuclear pores, and invagination of cytoplasm into the nuclear region. CONCLUSIONS: EM studies revealed high morphological frequency of specific ultrastructural changes in erythroblasts which facilitate prompt diagnosis of CDAI. Due to low specificity of BM LM findings, when BM EM is unavailable diagnostic approach should also include other inherited anemias.

Cdan1 Is Essential for Primitive Erythropoiesis.

Congenital dyserythropoietic anemia type I (CDA I) is an autosomal recessive disease characterized by moderate to severe macrocytic anemia and pathognomonic morphologic abnormalities of the erythroid precursors, including spongy heterochromatin. The disease is mainly caused by mutations in CDAN1 (encoding for Codanin-1). No patients with homozygous null type mutations have been described, and mouse null mutants die during early embryogenesis prior to the initiation of erythropoiesis. The cellular functions of Codanin-1 and the erythroid specificity of the phenotype remain elusive. To investigate the role of Codanin-1 in erythropoiesis, we crossed mice carrying the Cdan1 floxed allele (Cdan fl/fl ) with mice expressing Cre-recombinase under regulation of the erythropoietin receptor promoter (ErGFPcre). The resulting CdanΔEry transgenic embryos died at mid-gestation (E12.5-E13.5) from severe anemia, with very low numbers of circulating erythroblast. Transmission electron microscopy studies of primitive erythroblasts (E9.5) revealed the pathognomonic spongy heterochromatin. The morphology of CdanΔEry primitive erythroblasts demonstrated progressive development of dyserythropoiesis. Annexin V staining showed increases in both early and late-apoptotic erythroblasts compared to controls. Flow cytometry studies using the erythroid-specific cell-surface markers CD71 and Ter119 demonstrated that CdanΔEry erythroid progenitors do not undergo the semi-synchronous maturation characteristic of primitive erythroblasts. Gene expression studies aimed to evaluate the effect of Cdan1 depletion on erythropoiesis revealed a delay of ζ to α globin switch compared to controls. We also found increased expression of Gata2, Pu.1, and Runx1, which are known to inhibit terminal erythroid differentiation. Consistent with this data, our zebrafish model showed increased gata2 expression upon cdan1 knockdown. In summary, we demonstrated for the first time that Cdan1 is required for primitive erythropoiesis, while providing two experimental models for studying the role of Codanin-1 in erythropoiesis and in the pathogenesis of CDA type I.

[Whole exome sequencing analysis of compound heterozygous variants of CDAN1 gene in a Chinese family with non-immune hydrops fetalis].

OBJECTIVE: To study the clinical characteristics and genetic variants in a family with non-immune hydrops fetalis. METHODS: Peripheral blood samples were collected from a pregnant woman with suspected non-immune hydrops fetalis of the fetus for routine blood analysis, Rh typing and TORCH test. Amniotic fluid sample was collected for G-banded chromosomal karyotyping. The genomic DNA of the proband was extracted for analysis of chromosomal abnormalities using copy number variation sequencing. Whole-exome sequencing (Trios-WES) was performed on Illumina NovaSeq 6000 platform and exonic DNA was enriched using Agilent Sure Select XT Human All Exon V6. Sorting intolerant from tolerant (SIFT), I-mutant2, PolyPhen-2 and PROVEAN were used to predict the potential effects of amino acid substitution on protein function and splicing variation. The spatial structure of codanin-1 was modeled and visualized with Alpha Fold 2 and PyMOL 2.3 software, and the variants with potential clinical significance were confirmed by Sanger sequencing. RESULTS: Fetal ultrasound at 17 weeks of gestation showed extensive subcutaneous edema, ascites, pleural effusion, enlarged liver and spleen, thickened placenta and pericardium defect. NGS reveals that proband has carried c.2140C>T, p.R714W, and c.1264_1265delCT, p.L422* compound heterozygous variants of CDAN1 gene, which were found to be pathogenic and inherited from proband's father and mother respectively. CONCLUSION: We identified a novel heterozygous CDAN1 gene mutation causing fetal-onset congenital dyserythropoietic anemia type 1, which triggers non-immune hydrops fetalis.

Identification of CDAN1, C15ORF41 and SEC23B mutations in Chinese patients affected by congenital dyserythropoietic anemia.

Congenital dyserythropoietic anaemias (CDAs) are a group of rare haematological disorders characterized by ineffective erythropoiesis and dyserythropoiesis and reduced numbers of red cells, often with an abnormal morphology. Pathogenic defects in CDAN1, C15ORF41, SEC23B, KIF23, KLF1 and GATA1 genes have been identified in CDAs patients. In this study, we described 13 unrelated Chinese CDAs patients and identified 21 mutations, including 5 novel mutations in CDAN1 gene, and 5 novel mutations in SEC23B gene. Additionally, we predicted the molecular consequence of these missense mutations with Polymorphism Phenotyping v2 (Polyphen), Sorting Intolerant From Tolerant (SIFT), MutPred (http://mutpred1.mutdb.org/) and Protein Variation Effect Analyzer (Provean, http://provean.jcvi.org/seq_submit.php) and analyzed the conservation of the mutated amino acid among proteins from several mammalian species.

New Codanin-1 Gene Mutations in a Italian Patient with Congenital Dyserythropoietic Anemia Type I and Heterozygous Beta-Thalassemia.

Congenital dyserythropoietic anemia type I is an autosomal recessive disorder associated with macrocytic anemia, ineffective erythropoiesis, iron overloading and characterized by abnormal chromatin ultrastructure in erythroblasts such as internuclear chromatin bridges, spongy heterochromatin and invagination of the nuclear membrane. A 58-year-old Causasian man with chronic hemolytic anemia, heterozygous for ß (+) -globin IVS1, nt110 G>A mutation (causing abnormal alpha:beta globin chain ratio) showed clinical, laboratory and hematological features suggesting diagnosis of CDA1. Sequence analysis of CDA-related genes revealed compound heterozygosity for two novel mutations in the CDAN1 gene: a frameshift mutation 3367 del 4 (TTAG) in exon 25 and a missense mutation c.1811 G>T in exon 11 causing an aminoacid change from glycine to valine at codon 565 (G565V). One of the propositus' brothers showed the same gene mutations. As the CDA1 can mimic thalassemia, a frequent misdiagnosis is possible especially in countries where the prevalence of thalassemia is high. A strong clinical suspicion in patients who do not reveal a clear genetic basis for presumed thalassemia may help clinch the correct diagnosis.

Anemia diseritropoyética congénita tipo I: una mirada actualizada de sus bases moleculares, diagnóstico y tratamiento / Congenital dyserythropoietic anemia type I: an updated review about its molecular bases, diagnosis and treatment

Introducción: Las anemias diseritropoyéticas congénitas constituyen un grupo de trastornos hereditarios caracterizados por anemia refractaria, eritropoyesis ineficaz y alteraciones morfológicas de los eritroblastos. La anemia diseritropoyética congénita tipo I es la más frecuente, no obstante, constituye una rara enfermedad con particularidades morfológicas y moleculares. Objetivo: Analizar los aspectos más novedosos en cuanto a la patogenia molecular, el diagnóstico genético y el tratamiento de la anemia diseritropoyética congénita tipo I. Métodos: Se realizó una revisión de la literatura, en inglés y español. Se utilizaron motores de búsqueda como Google académico y Pubmed que permitió el acceso a artículos actualizados del tema. Se hizo un análisis y resumen de la bibliografía revisada. Análisis y síntesis de la información: La anemia diseritropoyética congénita tipo I es una enfermedad hereditaria autosómica recesiva. Se caracteriza por anemia de grado variable, reticulocitopenia, alteraciones morfológicas de la serie roja en la lámina periférica y un número elevado de eritroblastos binucleados conectados por puentes internucleares en el aspirado de médula ósea. Se han identificado múltiples alteraciones moleculares que involucran fundamentalmente a los genes CDAN1 y C15orf41. Las proteínas codificadas por estos genes participan en proceso vitales como el ciclo celular, la reparación del ADN y la transcripción de ARN. Conclusiones: El estudio de las bases moleculares de la anemia diseritropoyética congénita tipo I ha cambiado la perspectiva en el diagnóstico de esta enfermedad. Los protocolos de tratamiento son similares a otras anemias hemolíticas hereditarias aunque se destaca el uso del Interferón-α(AU)

Introduction: Congenital dyserythropoietic anemias belong to a group of hereditary disorders characterized by refractory anemia, ineffective erythropoiesis and morphological alterations of erythroblasts. Congenital dyserythropoietic anemia type I is the most frequent; however, it is a rare disease with morphological and molecular characteristics. Objective: To analyze the most updated aspects regarding molecular pathogenesis, genetic diagnosis and treatment of congenital dyserythropoietic anemia type I. Methods: A review of the literature in English and Spanish was carried out. Search engines such as Google Scholar and Pubmed were used, which allowed access to updated articles on the subject. An analysis and summary of the revised bibliography was carried out. Information analysis and synthesis: Congenital dyserythropoietic anemia type I is an autosomal recessive hereditary disease. It is characterized by anemia of variable degree, reticulocytopenia, morphological alterations of the red series in the peripheral lamina, and high number of binucleated erythroblasts connected by internuclear bridges in the bone marrow aspirate. Multiple molecular alterations have been identified, mainly involving the CDAN1 and C15orf41 genes. The proteins encoded by these genes participate in vital processes, such as the cell cycle, DNA repair, and RNA transcription. Conclusions: The study of the molecular bases of congenital dyserythropoietic anemia type I has changed the perspective concerning the diagnosis of this disease. Treatment protocols are similar to other hereditary hemolytic anemias, although the use of Interferon-α stands out(AU)

Anemia diseritropoyética congénita tipo 1: Presentación de un caso / Type 1 congenital dyserytropoieitc anemia: A case presentation

Las anemias diseritropoyéticas congénitas (ADC) son un grupo de trastornos heridatarios de la hematopoyesis caracterizados por anemia refractaria de severidad variable. Se distinguen 3 tipos fundamentales: 1, 2 y 3. El gen responsable de la ADC-1 (CDAN1) se localiza en el cromosoma 15q15, aunque estudios moleculares recientes evidencian la heterogeneidad de esta enfermedad. Se presenta una paciente de 3 años con diagnóstico de ADC-1 que a los 3 meses de edad comenzó con anemia severa, hiperbilirrubinemia indirecta, reticulocitosis ligera, altos requerimientos transfusionales y alteraciones del desarrollo pondoestatural dado por baja talla. La prueba de Ham fue negativa y en sangre periférica predominó la macrocitosis. En el examen de la médula ósea se observó diseritropoyesis con hiperplasia eritroide, hematopoyesis megaloblástica, precipitados intracitoplasmáticos, núcleos irregulares, cariorrexis, binuclearidad y puentes internucleares. No hubo respuesta al tratamiento con interferón alfa recombinante. La paciente se encuentra con tratamiento quelante con deferroxamina y se ha planteado la posibilidad de un trasplante de células progenitoras hematopoyéticas alogénico no relacionado

The congenital dyserytropoietic anemias (CDT) include a series of hematopoiesis hereditary disorders characterized by a refractory anemia of variable severity. There are three fundamental types: 1, 2 and 3. The gen accounted for CDT-1(CDAN1) is located in 15q15 chromosome, although recent studies demonstrate the heterogeneity of this disease. This is the case of a female patient aged 3 diagnosed with CDT-1who at three months old had a severe anemia, indirect hyperbilirubinemia, slight reticulocytosis, high transfusion requirements and stature disorders due to its low height. Ham’s was negative and in peripheral blood there was macrocytosis predominance. Bin bone marrow examination it was possible to observe dyserytropoiesis with erythroid hyperplasia, megaloblast hematopoiesis, intracytoplasm precipitates, irregular nuclei, karyorresis, binuclearization and internuclear bridges. There wasn’t response to treatment with the recombinant type α interferon. Patient is under chelation treatment with deferoxamine and it was proposed the possibility of no-related allogenic of hematopoietic parent cell