Natural history of congenital dyserythropoietic anemia type II
Nuffield Division of Clinical Laboratory Sciences, University of Oxford, Oxford, England, United Kingdom Blood
(Impact Factor: 10.45).
08/2001; 98(4):1258-60. DOI: 10.1182/blood.V98.4.1258
Congenital dyserythropoietic anemia type II (CDA-II) is an autosomal recessive disease characterized by anemia, jaundice, splenomegaly, and erythroblast multinuclearity. The natural history of the disease is unknown. The frequency, the relevance of complications, and the use of splenectomy are poorly defined. This study examined 98 patients from unrelated families enrolled in the International Registry of CDA-II. Retrospective data were obtained using an appropriate questionnaire. The mean age at presentation was 5.2 +/- 6.1 years. Anemia was present in 66% and jaundice in 53.4% of cases. The mean age at correct diagnosis was 15.9 +/- 11.8 years. Twenty-three percent of patients for whom data were available developed anemia during the neonatal period, and 10 of these individuals required transfusions. Splenectomy produced an increased hemoglobin (P <.001) and a reduced bilirubin level (P =.007) in comparison with values before splenectomy. Preliminary data indicate that iron overload occurs irrespective of the hemochromatosis genotype. (Blood. 2001;98:1258-1260)
Available from: Marcus Carden
- "The morphological aberrancies of CDA II, which include binucleated and multinucleated RBC precursor cells with membrane irregularities as seen on our patient's diagnostic bone marrow sample, are thought to be secondary to hypoglycosylation of erythrocyte membrane proteins   . Complications that have been reported include splenomegaly , gallstones, jaundice, and pulmonary failure . PAP is a rare disorder involving deposition of lipoproteinaceous material in alveoli and results in a deficit of surfactant clearance by pulmonary macrophages . "
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ABSTRACT: A two-year-old girl with congenital dyserythropoietic anemia (CDA) acutely developed fever, tachypnea, and increased oxygen requirement. Chest X-ray revealed bilateral interstitial infiltrates and mild cardiomegaly. Blood cultures grew no infectious agents, while pulmonary specimens grew cytomegalovirus (CMV). Treatment with intravenous ganciclovir was initiated but without response. Final cytologic preparations of bronchoalveolar lavage (BAL) fluid revealed eosinophilic amorphous material consistent with pulmonary alveolar proteinosis (PAP). CDA and PAP are extremely rare disorders in pediatrics. PAP should be considered in patients with hematological disorders who present with acute interstitial pneumonia, after infectious causes are ruled out.
Available from: Alessandra Iurlo
- "It cannot be excluded that some mutations may fall in the promoter or in the regulatory regions of the gene; moreover, some variants, for example large deletions or mutations that may activate a cryptic splice-site in an intron, are often difficult to identify and may not be detected by the normal panel of primers used for PCR amplification. The occurrence of SEC23B mutations in all patients was to some extent unexpected since it is known that about 10% of CDAII patients are not linked to chromosome 20 [Iolascon et al., 2001]; the lack of such cases in our series is likely to be due to the limited number of families investigated. "
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ABSTRACT: Congenital dyserythropoietic anemia type II (CDAII) is an autosomal recessive disease characterized by ineffective erythropoiesis, hemolysis, erythroblast morphological abnormalities, and hypoglycosylation of some red blood cell (RBC) membrane proteins. Recent studies indicated that CDAII is caused by a defect disturbing Golgi processing in erythroblasts. A linkage analysis located a candidate region on chromosome 20, termed the CDAN2 locus, in the majority of CDAII patients but the aberrant gene has not so far been elucidated. We used a proteomic-genomic approach to identify SEC23B as the candidate gene for CDAII by matching the recently published data on the cytoplasmic proteome of human RBCs with the chromosomic localization of CDAN2 locus. Sequencing analysis of SEC23B gene in 13 CDAII patients from 10 families revealed 12 different mutations: six missense (c.40C>T, c.325G>A, c.1043A>C, c.1489C>T, c.1808C>T, and c.2101C>T), two frameshift (c.428_428delAinsCG and c.1821delT), one splicing (c.689+1G>A), and three nonsense (c.568C>T, c.649C>T, and c.1660C>T). Mutations c.40C>T and c.325G>A were detected in unrelated patients. SEC23B is a member of the Sec23/Sec24 family, a component of the COPII coat protein complex involved in protein transport through membrane vesicles. Abnormalities in this gene are likely to disturb endoplasmic reticulum (ER)-to-Golgi trafficking, affecting different glycosylation pathways and ultimately accounting for the cellular phenotype observed in CDAII.
Available from: wisc.edu
- "Most cases have an Hb between 8 and 11 g/dl. The MCV is usually normal but occasional cases show a slight increase or decrease in MCV (Iolascon et al, 2001a; Heimpel et al, 2003). "
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ABSTRACT: The congenital dyserythropoietic anaemias (CDAs) are a heterogeneous group of diseases in which the anaemia is predominantly caused by dyserythropoiesis and marked ineffective erythropoiesis; three major (types I, II and III) and several minor subgroups have been identified. Additional information on the natural history of these conditions, the beneficial role of splenectomy in CDA type II and efficacy of interferon-alpha in type I have recently been reported. A disease gene has been localised to a chromosomal segment in the three major types and in CDA type I, a disease gene has been identified (CDANI). Mutations have been detected in both familial and sporadic cases but the predicted protein structure gives few clues as to its function. In both type I and II, there are cases unlinked to the identified localisations, suggesting genetic heterogeneity.
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