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.

A case of congenital dyserythropoietic anemia type IV.

Congenital dyserythropoietic anemias (CDAs) are displayed by ineffective erythropoiesis. The wide variety of phenotypes observed in CDA patients makes differential diagnosis difficult; identification of the genetic variants is crucial in clinical management. We report the fifth case of a patient with unclassified CDAs, after genetic study, with CDA type IV.

Sideroblastic anemia: functional study of two novel missense mutations in ALAS2.

BACKGROUND: X-linked sideroblastic anemia (XLSA) is a disorder characterized by decreased heme synthesis and mitochondrial iron overload with ringed sideroblasts in bone marrow. XLSA is caused by mutations in the erythroid-specific gene coding 5-aminolevulinate synthase (ALAS2). Anemia in XLSA is extremely variable, characteristically microcytic and hypochromic with poikilocytosis, and the red blood cell distribution width is increased and prominent dimorphism of the red cell population. Anemia in XLSA patients responds variably to supplementation with pyridoxine. METHODS AND RESULTS: We report four patients with XLSA and three mutations in ALAS2: c.611G>A (p.Arg204Gln), c.1218G>T (p.Leu406Phe) and c.1499A>G (p.Tyr500Cys). The in silico predictions of three ALAS2 mutations and the functional consequences of two ALAS2 mutations were assessed. We performed in silico analysis of these mutations using ten different softwares, and all of them predicted that the p.Tyr500Cys mutation was deleterious. The in vitro prokaryotic expression showed that the p.Leu406Phe and p.Tyr500Cys mutations reduced the ALAS2 specific activity (SA) to 14% and 7% of the control value, respectively. CONCLUSION: In view of the results obtained in this study, a clear relationship between genotype and phenotype cannot be established; clinical variability or severity of anemia may be influenced by allelic variants in other genes or transcription factors and environmental conditions.

Red blood cell disorders in recently arrived African immigrants to Gran Canaria, Spain.

BACKGROUND: In the last decade immigration to Europe has increased, with Africa being the source of a large number of immigrants. In addition to infections, this group has other less known health problems, such as erythrocyte abnormalities. METHODS: The objectives of this study were: the systematic evaluation of red cell abnormalities in 200 newly arrived asymptomatic African immigrants on the Canaries; the systematic evaluation of haemoglobinopathies and their characterization in this population; and the relationship of red blood cell disorders and parasitic infections. RESULTS: Of the studied immigrants 53 (26.5%) had red cell disorders according to their CBC parameters (Hb and/or MCV). In 48 people (24.0%) one or more etiologic diagnoses were made. Specifically, in order of frequency, a total of 26 structural haemoglobinopathies, 14 α-thalassemias, 2 ß-thalassemias and 14 iron deficiencies were diagnosed. There was a statistically significant association between the presence of anemia, microcytosis, structural haemoglobinopathies or α thalassemia and sub-Saharan origin. However, no statistically significant association between the abovementioned parameters and eosinophilia or helminthic infection was observed. CONCLUSIONS: These results suggest that, even in the presence of normal Hb and MCV values, including haemoglobinopathies in the initial screening of newly arrived sub-Saharan immigrants would be very useful.

Induction of apoptosis in leukemic cell lines treated with captopril, trandolapril and losartan: a new role in the treatment of leukaemia for these agents.

Renin-angiotensin system (RAS) in the bone marrow is related to proliferation and cellular differentiation. We investigated the effect of ACE inhibitors (ACEI) captopril (>1mM) and trandolapril (>0.05 mM) and losartan (0.2 mM) on K562 cell line and K562 transfected with c-myc, bcl-x and bcl-2 (KmycB, Kbclx and Kbcl2 respectively). RAS components, proliferation, apoptosis and c-myc expression were analyzed. ACEI and losartan inhibited cell growth, decreased c-myc expression and increased apoptosis. These effects seem to be associated to angiotensin II-induced Smad activation. This work offers a new possible line of treatment for some acute myeloid leukemias and a new area of clinical research.

[Molecular characterization of heterozygous beta-thalassemia in Lanzarote, Spain]. / Caracterización molecular de la betatalasemia en Lanzarote.

BACKGROUND AND OBJECTIVE: The aim of this study was to determine the molecular defects of heterozygous beta thalassaemia and to ascertain their distribution in Lanzarote. PATIENTS AND METHOD: Molecular characterization was achieved by real time polymerase chain reaction (RT-PCR LightCycler, Roche), PCR-ARMS (PCR-amplification reaction mutations system) and DNA sequencing on an automated DNA sequencer. RESULTS: Two hundred forty-three heterozygous beta thalassaemia carriers were included between July 1991 and February 2007. RT-PCR detected the molecular defect in 81% of the beta thalassaemia chromosomes analyzed [113 codon CD 39 (C --> T); 41 IVS-1-nt-110 (G --> A), 25 IVS 1-nt-1 (G --> A) and 19 IVS 1-nt-6 (T --> C)]. The remaining 12 molecular defects included the deletion 619 bp (7.8%) and the mutations -28 (A --> G), IVS1-nt-2 (T --> G), CD 41/42 (-TTCT), CD 8/9 (+G), CD 51 (-C), CD 22 (G --> T) and CD 24 (T --> A), CD 67 (-TG) and the novel mutation CD 20/21-TGGA. CONCLUSIONS: The distribution of the mutations is similar to that found in the Mediterranean area. The increasing migratory flow received in the Canary Islands may explain the emergence of new mutations not reported before in our area.