Congenital dyserythropoietic anemia type I presenting as persistent pulmonary hypertension of the newborn

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.

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.

Successful management of transfusion-dependent congenital dyserythropoietic anemia type 1b with interferon alfa-2a

The congenital dyserythropoietic anemias (CDAs) are a group of rare inherited blood disorders characterized by ineffective erythropoiesis as the principal cause of anemia. We present a child with CDA 1b-the rarest and least well-described type-due to a mutation in the C15orf41 gene. The patient presented with severe in utero and neonatal manifestations, typical peripheral limb anomalies as well as rarely reported cardiac manifestations, visual impairment, short stature, and hip dysplasia. Anemia was complicated by iron overload and pronounced extra medullary erythropoiesis leading to skull deformities. The patient responded to treatment with pegylated interferon alfa-2a.

Hematological disorders and pulmonary hypertension

Pulmonary hypertension (PH), a serious disorder with a high morbidity and mortality rate, is known to occur in a number of unrelated systemic diseases. Several hematological disorders such as sickle cell disease, thalassemia and myeloproliferative diseases develop PH which worsens the prognosis. Associated oxidant injury and vascular inflammation cause endothelial damage and dysfunction. Pulmonary vascular endothelial damage/dysfunction is an early event in PH resulting in the loss of vascular reactivity, activation of proliferative and antiapoptotic pathways leading to vascular remodeling, elevated pulmonary artery pressure, right ventricular hypertrophy and premature death. Hemolysis observed in hematological disorders leads to free hemoglobin which rapidly scavenges nitric oxide (NO), limiting its bioavailability, and leading to endothelial dysfunction. In addition, hemolysis releases arginase into the circulation which converts L-arginine to ornithine, thus bypassing NO production. Furthermore, treatments for hematological disorders such as immunosuppressive therapy, splenectomy, bone marrow transplantation, and radiation have been shown to contribute to the development of PH. Recent studies have shown deregulated iron homeostasis in patients with cardiopulmonary diseases including pulmonary arterial hypertension (PAH). Several studies have reported low iron levels in patients with idiopathic PAH, and iron deficiency is an important risk factor. This article reviews PH associated with hematological disorders and its mechanism; and iron homeostasis and its relevance to PH.

Fetal Anemia With Persistent Pulmonary Hypertension: A Report of 3 Cases

Fetal anemia may cause tissue hypoxia and hence has the potential to predispose to persistent pulmonary hypertension of the newborn (PPHN). Review articles and textbooks do not include severe anemia as a cause of PPHN. We report 3 cases of fetal anemia complicated by severe PPHN.

Persistent pulmonary hypertension of the newborn associated with severe congenital anemia of various etiologies

Among the many associated features of persistent pulmonary hypertension of the neonate (PPHN), severe congenital anemia has been described only occasionally and is not included in the list of conditions that may cause PPHN in the neonate. We describe the clinical course of a group of 12 full-term neonates with PPHN and congenital anemia due to congenital dyserythropoietic anemia (7/12), α thalasemia (1/12), Diamond-Blackfan (1/12), and epsilon gamma delta beta thalassemia (3/12). The association of congenital anemia and PPHN is more common than previously thought; it can exist with various etiologies and severity of anemia. Congenital anemia has not been described until now as a cause or risk factor for PPHN; it should be considered as such alone or in combination with other known causes to be recognized early and treated appropriately to improve outcome. In families with known cases of congenital anemia due to the above-mentioned diagnosis, closer prenatal follow-up should be offered to anticipate possible fetal distress and/or fetal anemia and PPHN after birth.

Congenital dyserythropoietic anemia type I presenting as persistent pulmonary hypertension with pigeon chest deformity

Congenital dyserythropoietic anemia (CDA) type-1 is a rare genetic disorder of ineffective erythropoiesis, which manifests in macrocytic anemia. We report a CDA1 patient who as a newborn presented with macrocytic anemia and persistent pulmonary hypertension of the newborn (PPHN) requiring mechanical ventilation. Post-infancy, the patient developed acral dysmorphism and pectus excavatum the latter rarely found in CDA1. Patient is a compound heterozygote for a known maternal-derived missense-mutation (c.1796A > G/p.Asn589Ser) and a novel paternal-derived deletion-mutation (c.1104_1106del/Phe365del) in CDAN1. This report highlights the importance of recognizing PPHN as a presenting symptom of CDA1 and expands the repertoire of the accompanying mutations and axial skeletal malformations.

Close to unraveling the secrets of congenital dyserythropoietic anemia types I and II

The congenital dyserythropoietic anemias are rare recessive disorders characterized by erythroblast multinuclearity, ineffective erythropoiesis, anemia and iron overload. In this perspective article, Drs. Iolascon and Delaunay examine genetic and clinical aspects of these inherited disorders.

Pulmonary Hypertension in Sickle Cell Disease: Mechanisms, Diagnosis, and Management

Pulmonary hypertension affects nearly one-third of adults with sickle cell disease and is related to hemolysis. Although pulmonary pressures are not as high as in other forms of pulmonary hypertension, sickle cell patients poorly tolerate even moderate elevations of pulmonary pressures, because this complication predicts short survival. Tricuspid regurgitant jet velocity measured noninvasively by echocardiography is an adequate tool to screen for pulmonary hypertension. Because patients with pulmonary hypertension are older and often severely affected by other vaso-occlusive complications, optimizing their treatment with hydroxyurea or transfusions is important. Newer agents such as sildenafil and bosentan have demonstrated efficacy in other forms of pulmonary hypertension, and future clinical trials may prove them helpful in sickle cell patients.

Clinical and laboratory manifestations of congenital dyserythropoietic anemia type I in a cohort of French children

Congenital dyserythropoietic anemia type I (CDA I) is a rare disorder of erythropoiesis. The objective of this study was to describe the clinical and laboratory manifestations, the diagnosis procedure, the therapeutic approaches and outcome in CDA I. The 12 patients included belong to the retrospective French Multicenter Study. Clinical and biologic data were compiled. Biologic tests included light and, in some cases, electron microscopy, ektacytometry, and red cell membrane protein electrophoresis. Neonatal manifestations (anemia, early jaundice, and/or splenomegaly) and bone abnormalities were present in 11 of the 12 and 6 of the 12 patients, respectively. CDA I was initially misdiagnosed in four children. By the time of diagnosis, anemia with reticulocytosis lower than expected in a hemolytic anemia was present in all patients. Bone marrow electron microscopy examination revealed characteristic findings in all nine children. Red cell membrane protein 4.1 was reduced in all five children. At least one transfusion was required in 11 of the 12 children. Interferon alpha2 corrected anemia in the three children who received monthly transfusions. CDA I is commonly misdiagnosed in children. It should be sought in patients with unexplained chronic anemia, especially when associated with neonatal manifestations, jaundice, splenomegaly, subnormal or low reticulocytosis, and congenital bone malformations.

A comprehensive study of the neonatal manifestations of congenital dyserythropoietic anemia type I

Congenital dyserythropoietic anemia (CDA) type I is an inherited disorder characterized by macrocytic anemia with pathognomonic morphologic ultrastructural features of the erythroid precursors. The authors recently cloned the CDAN1 gene and identified one founder missense mutation in all of their Bedouin patients. In a previous study, the authors found that the majority of their 31 Bedouin patients had anemia and jaundice during the first month of life and required blood transfusions; some had persistent pulmonary hypertension. In the present retrospective evaluation of 70 Bedouin patients with CDA type I, the authors more than doubled the number. Forty-five (64%) patients were symptomatic in the neonatal period, 29 (65%) had hepatomegaly, 24 (53%) had early jaundice, 11 (27%) were born small for gestational age, 7 (15%) had persistent pulmonary hypertension, and 6 (13%) had direct hyperbilirubinemia and another 6 (13%) had transient thrombocytopenia. Thirty-six of the symptomatic neonates (80%) required at least one blood transfusion. These results confirm the authors' previous findings and add neonatal manifestations not previously described, particularly hyperbilirubinemia and thrombocytopenia. Early diagnosis of CDA type I may be beneficial in light of the potential efficacy of alpha-interferon in avoiding transfusions in some patients.

Congenital dyserythropoietic anemia, type 1, in a polynesian patient: response to interferon alpha2b

The authors attempted to assess the utility of interferon alpha2b treatment in a Polynesian girl with a relatively severe form of congenital dyserythropoietic anemia, type 1. The diagnosis was established using routine hematologic and biochemical tests, light and electron microscopy, and electrophoresis of red cell membrane proteins. Response to the treatment was monitored using the blood count and reticulocyte count. The patient was age 14 when interferon treatment was started. Previously, she had been partially dependent on transfusions, and gallstones and iron overload had developed. The dose of interferon alpha2b was initially 3 x 10 units three times a week for 1 year and 3 x 10 units twice a week thereafter. On this treatment, hemoglobin and reticulocytes increased and transfusions became unnecessary. In keeping with a few previous reports, interferon alpha2b proved to be effective in congenital dyserythropoietic anemia, type 1. The patient became transfusion-independent. More cases need to be studied to optimize the dosage of interferon alpha2b and determine how long the treatment can be tolerated.

Male siblings with dyserythropoiesis, microcephaly and intrauterine growth retardation

Male siblings with intrauterine growth retardation, hydrops, mild liver dysfunction, chronic diarrhoea, failure to thrive and microcephaly are reported. In both patients, the intrauterine growth retardation was detected in the second trimester of pregnancy. Relatively severe early onset neonatal jaundice, microcytosis, anisocytosis and abnormal iron metabolism were also seen. Bone marrow examination in the second sibling showed marked ringed sideroblasts and multilobulated erythroblasts in late developmental stages. The brain was very small with enlarged cerebrospinal fluid space, a reduced number of gyri and a thin cortex. The clinical and laboratory findings in these patients appear to be unique.