Characterization of the interactions between Codanin-1 and C15Orf41, two proteins implicated in congenital dyserythropoietic anemia type I disease.

BACKGROUND: Congenital dyserythropoietic anemia type I (CDA I), is an autosomal recessive disease with macrocytic anemia in which erythroid precursors in the bone marrow exhibit pathognomonic abnormalities including spongy heterochromatin and chromatin bridges. We have shown previously that the gene mutated in CDA I encodes Codanin-1, a ubiquitously expressed and evolutionarily conserved large protein. Recently, an additional etiologic factor for CDA I was reported, C15Orf41, a predicted nuclease. Mutations in both CDAN1 and C15Orf41 genes results in very similar erythroid phenotype. However, the possible relationships between these two etiologic factors is not clear. RESULTS: We demonstrate here that Codanin-1 and C15Orf41 bind to each other, and that Codanin-1 stabilizes C15Orf41. C15Orf41 protein is mainly nuclear and Codanin-1 overexpression shifts it to the cytoplasm. Phylogenetic analyses demonstrated that even though Codanin-1 is an essential protein in mammals, it was lost from several diverse and unrelated animal taxa. Interestingly, C15Orf41 was eliminated in the exact same animal taxa. This is an extreme case of the Phylogenetic Profiling phenomenon, which strongly suggests common pathways for these two proteins. Lastly, as the 3D structure is more conserved through evolution than the protein sequence, we have used the Phyre2 alignment program to find structurally homologous proteins. We found that Codanin-1 is highly similar to CNOT1, a conserved protein which serves as a scaffold for proteins involved in mRNA stability and transcriptional control. CONCLUSIONS: The physical interaction and the stabilization of C15Orf41 by Codanin-1, combined with the phylogenetic co-existence and co-loss of these two proteins during evolution, suggest that the major function of the presumptive scaffold protein, Codanin-1, is to regulate C15Orf41 activities. The similarity between Codanin-1 and CNOT1 suggest that Codanin-1 is involved in RNA metabolism and activity, and opens up a new avenue for the study of the molecular pathways affected in CDAI.

Treatment of transfusion-dependent congenital dyserythropoietic anemia Type I patients with pegylated interferon alpha-2a.

OBJECTIVE: Pegylated IFN-α2a has been reported in two case reports as being efficacious in treating CDA-I patients. This study aims to assess its efficacy on a series of CDA-I patients. METHODS: Study sample consisted of seven CDA type 1 transfusion-dependent patients. They received pegylated interferon alpha-2a at an initial dose of 90-180 µg once a week, tapered according to clinical response and side effects. Good response was defined as Hb ≥ 10 g/dL for ≥3 months, partial response was defined as 7 ≤ Hb<10 g/dL for ≥3 months, and no response was defined as HB < 7 g/dL for over 3 months on treatment. Time to response was defined as the time needed to achieve hemoglobin levels ≥ 10 g/dL without transfusion. Patients were evaluated periodically by abdominal ultrasounds to rule out liver adenomas. RESULTS: Five patients (71%) had a good response to treatment. One patient stopped treatment due to side effects. One patient had partial response. One patient, with more severe phenotype and poor compliance, had poor response to treatment. No abnormal findings were found in ultrasound examination. No effect on serum ferritin level could be established. CONCLUSION: Pegylated interferon α2a therapy is efficacious in CDA-I patients with a reasonable safety profile.

A complex comprising C15ORF41 and Codanin-1: the products of two genes mutated in congenital dyserythropoietic anaemia type I (CDA-I).

Congenital dyserythropoietic anaemia (CDA) type I is a rare blood disorder characterised by moderate to severe macrocytic anaemia and hepatomegaly, with spongy heterochromatin and inter-nuclear bridges seen in bone marrow erythroblasts. The vast majority of cases of CDA type I are caused by mutations in the CDAN1 gene. The product of CDAN1 is Codanin-1, which interacts the histone chaperone ASF1 in the cytoplasm. Codanin-1 is a negative regulator of chromatin replication, sequestering ASF1 in the cytoplasm, restraining histone deposition and thereby limiting DNA replication. The remainder of CDA-I cases are caused by mutations in the C15ORF41 gene, but very little is known about the product of this gene. Here, we report that C15ORF41 forms a tight, near-stoichiometric complex with Codanin1 in human cells, interacting with the C-terminal region of Codanin-1. We present the characterisation of the C15ORF41-Codanin-1 complex in humans in cells and in vitro, and demonstrate that Codanin-1 appears to sequester C15ORF41 in the cytoplasm as previously shown for ASF1. The findings in this study have major implications for understanding the functions of C15ORF41 and Codanin-1, and the aetiology of CDA-I.

Chronic Recurrent Multifocal Osteomyelitis and Related Diseases-Update on Pathogenesis.

PURPOSE OF REVIEW: We focus on recent advances in the understanding of the genetic, molecular, immunologic, and environmental factors implicated in the pathogenesis of autoinflammatory bone diseases including the syndromic and non-syndromic forms of chronic recurrent multifocal osteomyelitis (CRMO). RECENT FINDINGS: Evidence implicating the IL-1 pathway in the pathogenesis of the Mendelian forms of CRMO is growing. LIPIN2 can regulate the NLRP3 inflammasome by affecting P2X7 receptor activation, and intracellular cholesterol can modulate P2X7R currents. Work in a mouse model of CRMO demonstrates that dietary manipulation can alter the microbiome and protect these mice from the development of sterile osteomyelitis in vivo. Although the genetic and immunologic basis of non-syndromic CRMO remains only partially understood, the IL-1 pathway is central to the pathogenesis in the syndromic autoinflammatory bone disorders. Recent work implicates lipids and the microbiome in sterile osteomyelitis.

An Unusual Hydrops Fetalis Associated with Compound Heterozygosity for Krüppel-like Factor 1 mutations.

Hydrops fetalis is commonly due to Hb Bart's (γ4) disease in South East Asia. Here, we report an unusual case of hydrops fetalis due to congenital dyserythropoietic anemia (CDA) associated with compound heterozygosity for Krüppel-like factor 1 (KLF1) gene mutations. Fetal cardiomegaly was first detected on routine mid-trimester scan in a pregnant woman with normal mean corpuscular volume (MCV) and Rhesus positive status. The fetus subsequently developed hydrops fetalis, and cordocentesis showed severe fetal anemia with a hemoglobin (Hb) level of 3.4 g/dL. Common causes of fetal anemia including Hb Bart's disease, parvovirus infection, and red cell antibodies were excluded. In view of the marked increase in erythroblasts at various stages of erythropoiesis, the diagnosis of CDA was suspected. We screened the couple for previously reported KLF1 gene mutations, showing that the mother was heterozygous for the c.525_526insCGGCGCC, p.Gly176Argfs*179 mutation, and her husband heterozygous for c.1012C>A, p.Pro338Thr mutation. The fetus was a compound heterozygote for these two KLF1 mutations. After counseling, repeated intrauterine transfusions were given at 27, 29, and 34 weeks' gestation; the hydrops fetalis was resolved. The baby was delivered at 34 weeks' gestation and required monthly blood transfusions but was otherwise thriving. Bone marrow aspiration at 10 months of age showed the features of ineffective erythropoiesis, compatible with CDA. In conclusion, hydrops fetalis can rarely be due to CDA associated with a compound heterozygous mutation for KLF1 gene mutations, and be managed by repeated intrauterine transfusions. Our present report adds to the wide clinical spectrum of KLF1 mutations.

Autoinflammatory bone disorders: update on immunologic abnormalities and clues about possible triggers.

PURPOSE OF REVIEW: To provide an update on the genetics and immunologic basis of autoinflammatory bone disorders including chronic recurrent multifocal osteomyelitis including the monogenic forms of the disease. RECENT FINDINGS: Ongoing research in murine, canine and human models of sterile bone inflammation has solidified the hypothesis that sterile bone inflammation can be genetically driven. Mutations in Pstpip2, LPIN2 and IL1RN have been identified in monogenic autoinflammatory bone disorders that have allowed more detailed dissection of the immunologic defects that can produce sterile osteomyelitis. Recent studies in murine chronic multifocal osteomyelitis, deficiency of the interleukin-1 receptor antagonist (DIRA), Majeed syndrome and SAPHO syndrome reveal abnormalities in innate immune system function. IL-1 pathway dysregulation is present in several of these disorders and blocking IL-1 therapeutically has resulted in control of disease in DIRA, Majeed syndrome and in some cases of SAPHO and CRMO. Basic research demonstrates the importance of the innate immune system in disease pathogenesis and offers clues about potential disease triggers. SUMMARY: Research and clinical data produced over the last several years support the important role of innate immunity in sterile osteomyelitis. Based on what has been learned in the monogenic autoinflammatory bone disorders, IL-1 is emerging as an important pathway in the development of sterile bone inflammation.

Congenital dyserythropoietic anemia type III (CDA III) is caused by a mutation in kinesin family member, KIF23.

Haplotype analysis and targeted next-generation resequencing allowed us to identify a mutation in the KIF23 gene and to show its association with an autosomal dominant form of congenital dyserythropoietic anemia type III (CDA III). The region at 15q23 where CDA III was mapped in a large Swedish family was targeted by array-based sequence capture in a female diagnosed with CDA III and her healthy sister. Prioritization of all detected sequence changes revealed 10 variants unique for the CDA III patient. Among those variants, a novel mutation c.2747C>G (p.P916R) was found in KIF23, which encodes mitotic kinesin-like protein 1 (MKLP1). This variant segregates with CDA III in the Swedish and American families but was not found in 356 control individuals. RNA expression of the 2 known splice isoforms of KIF23 as well as a novel one lacking the exons 17 and 18 was detected in a broad range of human tissues. RNA interference-based knock-down and rescue experiments demonstrated that the p.P916R mutation causes cytokinesis failure in HeLa cells, consistent with appearance of large multinucleated erythroblasts in CDA III patients. We conclude that CDA III is caused by a mutation in KIF23/MKLP1, a conserved mitotic kinesin crucial for cytokinesis.

Clinical care of children with sterile bone inflammation.

PURPOSE OF REVIEW: To review the current literature of sterile bone inflammation in childhood and to evaluate the evidence for clinical care including diagnostic methods and treatment. RECENT FINDINGS: Chronic noninfectious osteomyelitis includes several different entities marked by sterile bone inflammation associated with histologic evidence of a predominant neutrophil infiltration in the absence of autoantibodies and autoreactive T cells, some of which are associated with a genetic mutation. Whole body MRI is helpful in detecting asymptomatic lesions. Initial treatment with NSAIDs is usually sufficient to control symptoms as the bone heals. However, if the lesions persist and do not respond to first-line treatment, or involve the spine or hip, treatment with bisphosphonate will usually lead to a resolution of symptoms. Rarely, treatment with anti-TNF agents is required. SUMMARY: This review summarizes recent information on diagnosis, treatment and prognosis of disorders involving sterile bone inflammation in childhood. It also addresses the evolving differential diagnosis for autoinflammatory disorders that include sterile bone inflammation and presents a treatment algorithm for management.

Elevated growth differentiation factor 15 expression in patients with congenital dyserythropoietic anemia type I.

Congenital dyserythropoietic anemia (CDA) is a rare group of red blood cell disorders characterized by ineffective erythropoiesis and increased iron absorption. To determine whether growth differentation factor 15 (GDF15) hyper-expression is associated with the ineffective erythropoiesis and iron-loading complications of CDA type I (CDA I), GDF15 levels and other markers of erythropoiesis and iron overload were studied in blood from 17 CDA I patients. Significantly higher levels of GDF15 were detected among the CDA I patients (10 239 +/- 3049 pg/mL) compared with healthy volunteers (269 +/- 238 pg/mL). In addition, GDF15 correlated significantly with several erythropoietic and iron parameters including Hepcidin-25, Ferritin, and Hepcidin-25/Ferritin ratios. These novel results suggest that CDA I patients express very high levels of serum GDF15, and that GDF15 contributes to the inappropriate suppression of hepcidin with subsequent secondary hemochromatosis.

Dyserythropoiesis in 105 patients with visceral leishmaniasis.

Hematologists in the developing world are increasingly involved in diagnosing parasitic diseases that involve the bone marrow. With a worldwide annual incidence of half a million cases and 12 million infected people, visceral leishmaniasis is one such serious disease. It mainly affects malnourishedand economically underprivileged children. Recently, this disease has been seen in acquired immunodeficiency syndrome patients and in travelers to endemic areas. Over an 18-year period, 442 marrow examination requests were received by our department, and 105 cases of visceral leishmaniasis were diagnosed from findings of Leishman-Donovan bodies. Prominent nuclear dyserythropoiesis was shown in 17 patients, 14 of whom had the frank type that is uniquely seen in congenital dyserythropoietic anemia type II. Most of these cases showed an extremely low degree of marrow parasitemia. This degree of nuclear dyserythropoiesis was not found in the majority of the marrows in which parasites were more easily detected. There is a direct and negative correlationbetween frank nuclear dyserythropoiesis and marrow parasitemia. Extended microscopical examination is recommended for the detection of Leishman-Donovan bodies in cases of suspected visceral leishmaniasis when frank dyserythropoiesis is a prominent feature. It is possible that both frank nuclear dyserythropoiesis and marrow parasitemia are etiologically under the influence of a common chemokine or cytokine.

Piebaldism associated with congenital dyserythropoietic anemia type II (HEMPAS).

Congenital dyserythropoietic anemias (CDAs) are a group of relatively rare inherited anemias. They are characterized by ineffective erythropoiesis and classified as three major groups and a number of variants. CDA type II, also known as hereditary erythroblastic multinuclearity with a positive acidified serum test (HEMPAS), is the most frequent one. A number of associations with CDA II have been reported, although each described only one or a few patients. Here we presented a piebald woman with vaginal atresia who was tested for anemia and diagnosed as CDA type II. Piebaldism and anemia association were previously described in the mouse. Our case was the first that shows the features of both piebaldism and CDA in the same patient. This association may suggest a stem cell defect to cause both hematopoietic and cutaneous manifestations.

Diseases of aberrant glycosylation.

Recently a defective glycosylation of glycoconjugates has been implicated in the pathogenesis of a number of heritable or acquired diseases of humans. Herein I discuss them under the name of diseases of aberrant glycosylation. These are: congenital dyserythropoietic anemia type II, carbohydrate-deficient glycoprotein syndrome, I-cell disease, galactosemia in subjects on galactose-free diet, variants of leukocyte adhesion deficiency, and of Ehlers-Danlos syndrome, paroxysmal nocturnal hemoglobinuria, and Tn syndrome. Regarding the present views on the function of glycoconjugates it is probably significant that in most instances defective or missing glycoproteins (or proteoglycans) but not glycosphingolipids, are probably involved in the pathogenesis of these diseases.

Identification of a novel simian parvovirus in cynomolgus monkeys with severe anemia. A paradigm of human B19 parvovirus infection.

Although human B19 parvovirus infection has been clearly associated with a number of distinct syndromes (including severe anemia, abortion, and arthritis), detailed knowledge of its pathogenesis has been hindered by the lack of a suitable animal model. We have identified a novel simian parvovirus in cynomolgus monkeys with severe anemia. Sequencing of a 723-bp fragment of cloned viral DNA extracted from serum revealed that the simian parvovirus has 65% homology at the DNA level with the human B19 parvovirus but little homology with other known parvoviruses. Light microscopic examination of bone marrow from infected animals showed intranuclear inclusion bodies, and ultrastructural studies showed viral arrays characteristic of parvoviruses. Another striking feature was the presence of marked dyserythropoiesis in cells of the erythroid lineage, raising the possibility that B19 parvovirus infection may underlie related dyserythropoietic syndromes in human beings. Affected animals had concurrent infection with the immunosuppressive type D simian retrovirus, analogous to HIV patients who develop severe anemia because of infection with B19 parvovirus. The remarkable similarities between the simian and B19 parvoviruses suggest that experimentally infected cynomolgus monkeys may serve as a useful animal model of human B19 infection.

[Morphological studies of erythrocytes in congenital dyserythropoietic anemia type II]. / Badania morfologiczne erytrocytów we wrodzonej anemii dyserytropoetycznej typ II.

The etiology of congenital dyserythropoietic anemia (CDA) type II is unknown. The diagnosis is based on morphologic and immunologic criteria. We present three girls with well documented CDA II who were followed for 5-8 years. The anemia was mild, progressive body iron overload was found. In none of the girls splenectomy was indicated. Morphologic features of ++erythrocytes and bone marrow erythroid cells were studied by means of light and electron microscopy. Up to 45% of erythrocytes showed invaginations with endocytic cisterns and shape abnormalities (echinocytes, anisocytosis, microcytosis). Typical abnormalities of the external surface of RBC membrane: invaginations, depressions, pits and plaques were shown in the scanning electron microscopic studies. Our studies indicate that the morphological features of erythrocyte in our patients may be consequence of the biochemical changes in the membranes and may contribute to the shortened life span of erythrocytes in patients with CDA II.