ABSTRACT
Overall survival of patients classified according to the European LeukemiaNet 2020 classification. Chronic phase (CP), accelerated phase (AP), blast crisis (BC), low risk (LR), intermediate risk (IR), high risk (HR).
Subject(s)
Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Blast Crisis/drug therapy , Protein Kinase Inhibitors/therapeutic useABSTRACT
BACKGROUND: Unmet medical needs remain in patients with red blood cell transfusion-dependent (RBC-TD) lower-risk myelodysplastic syndromes (LR-MDS) who are not responding to or are ineligible for erythropoiesis-stimulating agents (ESAs). Imetelstat, a competitive telomerase inhibitor, showed promising results in a phase 2 trial. We aimed to compare the RBC transfusion independence (RBC-TI) rate with imetelstat versus placebo in patients with RBC-TD LR-MDS. METHODS: In phase 3 of IMerge, a double-blind, placebo-controlled trial conducted in 118 sites including university hospitals, cancer centres, and outpatient clinics in 17 countries, patients (aged ≥18 years) with ESA-relapsed, ESA-refractory, or ESA-ineligible LR-MDS (low or intermediate-1 risk disease as per International Prognostic Scoring System [IPSS] criteria) were randomly assigned via a computer-generated schedule (2:1) to receive imetelstat 7·5 mg/kg or placebo, administered as a 2-h intravenous infusion, every 4 weeks until disease progression, unacceptable toxic effects, or withdrawal of consent. Randomisation was stratified by previous RBC transfusion burden and IPSS risk group. Patients, investigators, and those analysing the data were masked to group assignment. The primary endpoint was 8-week RBC-TI, defined as the proportion of patients without RBC transfusions for at least 8 consecutive weeks starting on the day of randomisation until subsequent anti-cancer therapy, if any. Primary efficacy analyses were performed in the intention-to-treat population, and safety analyses were conducted in patients who received at least one dose of trial medication or placebo. This trial is registered with ClinicalTrials.gov (NCT02598661; substudy active and recruiting). FINDINGS: Between Sept 11, 2019, and Oct 13, 2021, 178 patients were enrolled and randomly assigned (118 to imetelstat and 60 to placebo). 111 (62%) were male and 67 (38%) were female. 91 (77%) of 118 patients had discontinued treatment by data cutoff in the imetelstat group versus 45 (75%) in the placebo group; a further one patient in the placebo group did not receive treatment. Median follow-up was 19·5 months (IQR 12·0-23·4) in the imetelstat group and 17·5 months (12·1-22·7) in the placebo group. In the imetelstat group, 47 (40% [95% CI 30·9-49·3]) patients had an RBC-TI of at least 8 weeks versus nine (15% [7·1-26·6]) in the placebo group (rate difference 25% [9·9 to 36·9]; p=0·0008). Overall, 107 (91%) of 118 patients receiving imetelstat and 28 (47%) of 59 patients receiving placebo had grade 3-4 treatment-emergent adverse events. The most common treatment-emergent grade 3-4 adverse events in patients taking imetelstat were neutropenia (80 [68%] patients who received imetelstat vs two [3%] who received placebo) and thrombocytopenia (73 [62%] vs five [8%]). No treatment-related deaths were reported. INTERPRETATION: Imetelstat offers a novel mechanism of action with durable transfusion independence (approximately 1 year) and disease-modifying activity for heavily transfused patients with LR-MDS who are not responding to or are ineligible for ESAs. FUNDING: Janssen Research & Development before April 18, 2019, and Geron Corporation thereafter.
Subject(s)
Myelodysplastic Syndromes , Oligonucleotides , Thrombocytopenia , Humans , Male , Female , Adolescent , Adult , Treatment Outcome , Erythropoiesis , Myelodysplastic Syndromes/drug therapy , Thrombocytopenia/drug therapy , Double-Blind Method , Antineoplastic Combined Chemotherapy ProtocolsABSTRACT
Membrane transporters are important determinants of drug bioavailability. Their expression and activity affect the intracellular drug concentration in leukemic cells impacting response to therapy. Pharmacogenomics represents genetic markers that reflect allele arrangement of genes encoding drug transporters associated with treatment response. In previous work, we identified SNP rs460089 located in the promotor of SLC22A4 gene encoding imatinib transporter OCTN1 as influential on response of patients with chronic myeloid leukemia treated with imatinib. Patients with rs460089-GC pharmacogenotype had significantly superior response to first-line imatinib treatment compared to patients with rs460089-GG. This study investigated whether pharmacogenotypes of rs460089 are associated with sustainability of treatment-free remission (TFR) in patients from the EUROpean Stop Kinase Inhibitor (EURO-SKI) trial. In the learning sample, 176 patients showed a significantly higher 6-month probability of molecular relapse free survival (MRFS) in patients with GC genotype (73%, 95% CI: 60-82%) compared to patients with GG (51%, 95% CI: 41-61%). Also over time, patients with GC genotype had significantly higher MRFS probabilities compared with patients with GG (HR: 0.474, 95% CI: 0.280-0.802, p = 0.0054). Both results were validated with data on 93 patients from the Polish STOP imatinib study. In multiple regression models, in addition to the investigated genotype, duration of TKI therapy (EURO-SKI trial) and duration of deep molecular response (Polish study) were identified as independent prognostic factors. The SNP rs460089 was found as an independent predictor of TFR.
Subject(s)
Antineoplastic Agents , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Humans , Imatinib Mesylate/therapeutic use , Prognosis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Antineoplastic Agents/adverse effects , Protein Kinase Inhibitors/therapeutic use , Membrane Transport Proteins/therapeutic use , Treatment OutcomeABSTRACT
GATA2 deficiency was first identified in 2011 and have been reported over 500 individuals with GATA2 mutations. The onset of symptoms ranges from early childhood to late adulthood but very often the diagnosis is made between adolescence and early adulthood. These patients can be relatively asymptomatic or have life threatening diseaseas (myelodysplastic syndrome, acute leukemia). We describe case of 30-years old women with GATA2 novel mutation who present by primary lymphedema, myelodysplastic changes in bone marrow, monocytopenia and history of several recurrent infections (bacterial, mycobacterial). The case illustrates the diagnostic difficulties in identifying GATA2 deficiencies.
ABSTRACT
The heterogeneous nature of myelodysplastic syndrome (MDS) brings a very variable prognosis of patients with the need for individualized treatment. The prognosis and treatment depend on the conventional determination of IPSS (International Prognostic Scoring System) and its revised form IPSS-R, which divides patients into lower and higher risk groups. Treatment of patients with lower risk of MDS include the improvement of cytopenia, especially anemia. The goal of treatment in patients with higher risk of MDS is delaying disease progression and improve patient survival. The only curative method for therapy of MDS is allogeneic hematopoietic stem cell transplantation (HSCT), howewer it is rarely applicable due to the age and comorbidities of patients.
Subject(s)
Hematopoietic Stem Cell Transplantation , Myelodysplastic Syndromes , Disease Progression , Humans , Prognosis , RiskABSTRACT
To evaluate long-term real-life results of dasatinib therapy among chronic phase chronic myeloid leukemia patients resistant or intolerant to imatinib, we retrospectively analyzed data of 118 patients treated in centers participating in the database INFINITY. With median follow-up of 37 months, estimated 5-year cumulative incidences of complete cytogenetic and major molecular responses were 78% and 68%, respectively. The estimated 5-year probability of overall survival (OS) and event-free survival (EFS) were 86% and 83%, respectively. Both OS and EFS were significantly improved among patients with BCR-ABL1 transcript level ≤10% at 3 months. Dasatinib toxicity was tolerable however persistent in almost half our patients, even after years of therapy. Pleural effusion occurred in 29% of patients and was responsible for 30% of dasatinib discontinuations. Our results confirmed very good efficacy and acceptable toxicity of dasatinib in second line setting and support the evidence and importance of high-quality real-life CML patient management.
Subject(s)
Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Leukemia, Myeloid, Chronic-Phase , Dasatinib/adverse effects , Humans , Imatinib Mesylate/adverse effects , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myeloid, Chronic-Phase/drug therapy , Leukemia, Myeloid, Chronic-Phase/genetics , Protein Kinase Inhibitors/adverse effects , Retrospective Studies , Treatment OutcomeSubject(s)
Antineoplastic Agents , Cardiovascular Diseases , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/etiology , Heart Disease Risk Factors , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Imatinib Mesylate/adverse effects , Lipids , Prospective Studies , Protein Kinase Inhibitors , Pyrimidines , Risk FactorsABSTRACT
We retrospectively evaluated the role of age and dosage in 372 CML patients (170 women, 202 men) treated with first-line imatinib (IMA) from the records of the CAMELIA registry. The median follow-up of the patients was 82.3 (18.0-177.3) months. The treatment results of 80 elderly patients aged over 65 years at diagnosis were compared in analysis "A" with those of 292 younger patients and in analysis "B" with those of 90 patients younger than 40 and 202 patients aged 40-64. The elderly patients had statistically adverse values of the Sokal, ELTS, and ECOG scores and Charlson comorbidity index in both analyses (p from = 0.012 to ≤ 0.001). Despite a more frequent use of a daily dose lower than 400 mg - in 31 elderly patients (38.8%) than in 45 younger ones (15.4%) (p < 0.001), there were no statistically significant differences in the achievement of optimal haematological, cytogenetic, and molecular responses according to the ELN criteria in both the analyses, A and B. The comparisons of overall survival with CML-related death (OSCML) and event-free survival (EFS) were insignificant inanalysis A (p = 0.07 and 0.396, respectively) but progression-free survival (PFS) differed significantly (p = 0.007). In analysis B OSCML and PFS differed significantly (p = 0.027 and 0.003) but EFS was similar (p = 0.351). Elderly patients with a sustained dose of IMA of 400 mg/day have insignificantly better OS, PFS, and EFS compared to patients treated with a lower dosage of IMA. The results in the treatment of the elderly CML patients were comparable with those of the younger ones in terms of the probabilities of the achievement of optimal ELN responses. However, the results for the survival probabilities were influenced by age and the IMA dosage.
Subject(s)
Antineoplastic Agents/therapeutic use , Imatinib Mesylate/therapeutic use , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Registries/statistics & numerical data , Adult , Age Factors , Aged , Aged, 80 and over , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Middle Aged , Prognosis , Retrospective Studies , Survival RateABSTRACT
INTRODUCTION: Imatinib mesylate is the drug of choice for patients with chronic myeloid leukemia (CML). Imatinib pharmacokinetics is affected by a number of transport proteins and enzymes. MATERIAL AND METHODS: In the present study we evaluated the association of eight polymorphisms in the seven genes CYP3A5*3 (rs776746), CYP3A4*1 (rs2740574), CYP2C9*3 (rs1057910), SLC22A1 (rs683369), ABCB1 (rs1045642, rs1128503), ABCG2 (rs2231142) and ABCC2 (rs717620) with imatinib plasma level and achieving an optimal clinical response in 112 CML patients (53 men and 59 women). RESULTS: No association was found between the examined polymorphisms in rs776746, rs2740574, rs1057910, rs683369, rs1045642, rs1128503, rs2231142, rs717620 and the achieved imatinib plasma level. The influence of rs776746 (CYP3A5*3) on the achievement of a complete cytogenetic response (CCyR) at 6 months was borderline non-significant (p = 0.06). Furthermore, no association was demonstrated between rs776746 polymorphisms and the achievement of a major molecular response (MMR) at 12 or 18 months. Polymorphisms rs776746, rs2740574, rs1057910, rs683369, rs1045642, rs1128503, rs2231142, rs717620 showed no impact on the optimal therapeutic response. CONCLUSIONS: Despite the results of some other studies, no other polymorphism we analyzed was associated with imatinib plasma level or clinical response. The treatment outcomes cannot be predicted using the candidate gene approach and treatment decisions cannot be made according to the polymorphisms investigated in this study.
Subject(s)
Antineoplastic Agents/adverse effects , Glucose Intolerance/chemically induced , Insulin Resistance , Protein Kinase Inhibitors/adverse effects , Pyrimidines/adverse effects , Anthropometry , Dasatinib/adverse effects , Glucose Intolerance/physiopathology , Humans , Hyperinsulinism/chemically induced , Hyperinsulinism/physiopathology , Imatinib Mesylate/adverse effects , Insulin/blood , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Male , Prospective StudiesABSTRACT
BACKGROUND: Through high-throughput next-generation sequencing of promoters of solute carrier and ATP-binding cassette genes, which encode drug transporters, we aimed to identify SNPs associated with the response to imatinib administered for first-line treatment of patients with chronic myeloid leukemia. METHODS: In silico analysis using publicly available databases was done to select the SLC and ABC genes and their promoters for the next-generation sequencing. SNPs associated with the imatinib response were identified using Fisher's exact probability tests and subjected to the linkage disequilibrium analyses with regulatory loci of concerned genes. We analyzed cumulative achievement of major molecular response and probability of event free survival in relation to identified SNP genotypes in 129 CML patients and performed multivariate analysis for determination of genotypes as independent predictors of outcome. Gene expression analysis of eight cell lines naturally carrying different genotypes was performed to outline an impact of genotypes on the gene expression. RESULTS: We observed significant differences in the frequencies of the rs460089-GC and rs460089-GG (SLC22A4) genotypes among rs2631365-TC (SLC22A5) genotype carriers that were associated with optimal and non-optimal responses, respectively. Loci rs460089 and rs2631365 were in highly significant linkage disequilibrium with 12 regulatory loci in introns of SLC22A4 and SLC22A5 encoding imatinib transporters. Genotype association analysis with the response to imatinib indicated that rs460089-GC carriers had a significantly higher probability of achieving a stable major molecular response (BCR-ABL1 transcript level below or equal to 0.1% in the international scale). In contrast, the rs460089-GG represented a risk factor for imatinib failure, which was significantly higher in rs460089-GG_rs2631365-TC carriers. CONCLUSIONS: This exploratory study depicted potentially important genetic markers predicting outcome of imatinib treatment, which may be helpful for tailoring therapy in clinical practice.
Subject(s)
Antineoplastic Agents/administration & dosage , Imatinib Mesylate/administration & dosage , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Organic Cation Transport Proteins/genetics , Polymorphism, Single Nucleotide , Solute Carrier Family 22 Member 5/genetics , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Female , Genotype , High-Throughput Nucleotide Sequencing/methods , Humans , Imatinib Mesylate/therapeutic use , K562 Cells , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Linkage Disequilibrium , Male , Mutation Rate , Promoter Regions, Genetic , Sequence Analysis, DNA/methods , Symporters , Treatment OutcomeABSTRACT
BACKGROUND: A combination of low-dose thalidomide and corticosteroids is a treatment option for anaemic patients with primary myelofibrosis (PMF) who are not eligible for allogeneic hematopoietic stem cell transplantation. METHODS: We describe the outcomes of 13 patients with PMF treated with thalidomide 50 mg daily in combination with prednisone 0.5 mg/kg daily. Treatment responses were seen in 10/13 (77%) patients with a median onset of therapeutic effect at 4 weeks (range 3-7 weeks) after treatment initiation. Improvements of anaemia and thrombocytopenia and reduction in splenomegaly were observed in 70%, 38%, and 30% of patients, respectively. Four of six initially transfusion-dependent patients became transfusion independent following the therapy. The median duration of treatment response was 18 months (range 3-35 months). The treatment was well tolerated, with only one patient discontinuing therapy due to toxicity. Responders included both patients with and without JAK2 V617F, and included patients with both newly diagnosed and longstanding PMF. CONCLUSIONS: Our retrospective analysis confirmed that the therapy with low-doses thalidomide with prednisone in patients with PMF achieves significant response rate in anaemia with low treatment toxicity.
Subject(s)
Anemia, Aplastic/drug therapy , Prednisone/administration & dosage , Primary Myelofibrosis/drug therapy , Thalidomide/administration & dosage , Aged , Aged, 80 and over , Anemia, Aplastic/blood , Dose-Response Relationship, Drug , Drug Therapy, Combination , Female , Humans , Male , Middle Aged , Platelet Count , Primary Myelofibrosis/bloodABSTRACT
INTRODUCTION: Treatment of chronic myeloid leukemia (CML) with tyrosine kinase inhibitors (TKI) has significantly changed the survival of patients of all age categories. In our work, we have tried retrospectively to analyze a therapeutic response and toxicity of imatinib according to age of patients ( 60 years vs > 60 years). Patients have started treatment with imatinib in 2001-2013 in our department. The duration of treatment was at least 18 months. PATIENTS AND METHODS: The whole group contains 103 patients (52 women, 51 men) with a median age at diagnosis of CML 55 years (range 19-88 years). The first group includes 68 the younger patients (31 women, 37 men) with a median age at diagnosis 43 years (range 19-59 years) and the second group 35 the elderly patients (21 women, 14 men) with a median age at diagnosis 70 years (range 61-86 years). Median imatinib dose in both groups was the same - 400 mg per day (range 200-600 mg). RESULTS: In the elderly patients we observed higher rates of hematological toxicities (p = 0.0059). After 12 months treatment, a complete cytogenetic response (CCyR) was achieved in 90 % of younger patients and in 74 % of the elderly patients, respectively. Major molecular response (MMR) at 18 months treatment was achieved in 79 % of the younger group and in 63 % of the elderly group. CONCLUSION: The results represent in both groups very good therapeutic response independent of age of patients at the time of CML diagnosis.
Subject(s)
Imatinib Mesylate/therapeutic use , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Adult , Age Factors , Aged , Aged, 80 and over , Female , Humans , Imatinib Mesylate/adverse effects , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis , Male , Middle Aged , Remission Induction , Retrospective Studies , Treatment Outcome , Young AdultABSTRACT
Myelodysplastic syndrome (MDS) is a common hematological disease in patients over sixty. Despite intensive research, the therapy of this heterogeneous blood disease is complicated. In recent years, two new therapeutic approaches have been proposed: immunomodulation and demethylation therapy. Immunomodulation therapy with lenalidomide represents a meaningful advance in the treatment of anemic patients, specifically those with 5q- aberrations. As much as 60-70% of patients respond and achieve transfusion independence. We present the initial lenalidomide experience of the Czech MDS group. We analyze Czech MDS register data of 34 (31 female; 3 male; median age 69 years) chronically transfused low risk MDS patients with 5q- aberration treated by lenalidomide. Twenty-seven (79.4%) patients were diagnosed with 5q- syndrome, 5 patients with refractory anemia with multilineage dysplasia, 1 patient with refractory anemia with excess of blasts 1, and 1 patient with myelodysplastic/myeloproliferative unclassified. Response, as represented by achieving complete transfusion independence, was achieved in 91% of patients. A true 5q- syndrome diagnosis in most our patients may be responsible for such a high response rate. Complete cytogenetic response was reached in 15% of patients and partial cytogenetic response in 67%, within a median time of 12 months. TP53 mutation was detected in 15% (3 from 18 tested) and 2 of these patients progressed to higher grade MDS. The majority of patients tolerated lenalidomide very well. Based on this albeit small study, we present our findings of high lenalidomide efficacy as well as the basic principles and problems of lenalidomide therapy.
Subject(s)
Chromosome Deletion , Chromosomes, Human, Pair 5 , Myelodysplastic Syndromes/drug therapy , Thalidomide/analogs & derivatives , Adult , Aged , Aged, 80 and over , Female , Humans , Immunologic Factors/therapeutic use , Lenalidomide , Male , Middle Aged , Myelodysplastic Syndromes/genetics , Thalidomide/therapeutic useABSTRACT
This multicentre study focused on monitoring imatinib mesylate (IMA) trough plasma (Ctrough ) and intracellular (IMA Cintrac ) concentrations in 228 chronic myelogenous leukaemia patients. The median of measured IMA Ctrough in our patient group was 905.8 ng ml (range: 27.7-4628.1 ng/ml). We found a correlation between IMA Ctrough and alpha 1-acid glycoprotein plasma concentrations (rS = 0.42; p < 0.001). All other analysed parameters revealed only weak (gender, dose of IMA per kg) or not significant (age, albumin, creatinine plasma concentration or body mass index) impact on measured IMA Ctrough. The IMA Ctrough decreased during the first 6 months and significantly increased later during treatment. The IMA Ctrough at the first month of therapy did not differ between patients with and without an optimal response at the 12th (p = 0.724) and 18th month (p = 0.135) of therapy. There were no significant differences in medians of IMA Ctrough between both groups measured during the first year of treatment. The IMA Cintrac during the first month were not different between patients with and without an optimal response at the 6th (p = 0.273) and the 12th month (p = 0.193) of therapy. Our data obtained from real life clinical practice did not find a benefit of routine and regular IMA Ctrough nor IMA Cintrac therapeutic drug monitoring in chronic myelogenous leukaemia patients or for subsequent adjustments of the IMA dose based on these results. Moreover, actual alpha 1-acid glycoprotein plasma concentration should be used for proper interpretation of IMA Ctrough results.
Subject(s)
Antineoplastic Agents/blood , Antineoplastic Agents/therapeutic use , Benzamides/blood , Benzamides/therapeutic use , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/blood , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Piperazines/blood , Piperazines/therapeutic use , Pyrimidines/blood , Pyrimidines/therapeutic use , Adult , Aged , Aged, 80 and over , Antineoplastic Agents/pharmacokinetics , Benzamides/pharmacokinetics , Female , Humans , Imatinib Mesylate , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Male , Middle Aged , Piperazines/pharmacokinetics , Pyrimidines/pharmacokinetics , Treatment Outcome , Young AdultABSTRACT
One hundred thirteen patients with myelodysplastic syndromes (MDS) with <10% of bone marrow blasts received either deferiprone in a daily dose of 40-90 mg/kg (48 patients) or deferasirox in a daily dose of 10-40 mg/kg (65 patients). Median duration of treatment was 10,9 months for deferiprone and 13,7 months for deferasirox. A substantial reduction of iron stores evaluated as a decrease in serum ferritin of more than 50% of pretreatment level was achieved in 18 patients in deferasirox group (27.7%) but not in any patient treated with deferiprone, The incidence of adverse effects (mostly gastrointestinal symptoms) was similar after administration of both the drugs. The symptoms of deferasirox toxicity were mild and mostly transient and no drug related myelosuppresive effect was observed in contrast to deferiprone where agranulocytosis occurred in 4% of patients and the treatment had to be discontinued due to side effects in 20% of patients. The results confirmed the usefulness of deferasirox as an effective and safe iron chelator in MDS patients and indication of deferiprone as an alternative treatment only in patients with mild or moderate iron overload clearly not indicated for deferasirox.
Subject(s)
Benzoates/therapeutic use , Iron Chelating Agents/therapeutic use , Iron Overload/drug therapy , Iron Overload/etiology , Myelodysplastic Syndromes/therapy , Pyridones/therapeutic use , Transfusion Reaction , Triazoles/therapeutic use , Adult , Aged , Aged, 80 and over , Chelation Therapy/adverse effects , Chelation Therapy/statistics & numerical data , Deferasirox , Deferiprone , Female , Ferritins/blood , Humans , Iron Overload/epidemiology , Male , Middle Aged , Myelodysplastic Syndromes/blood , Myelodysplastic Syndromes/complications , Myelodysplastic Syndromes/epidemiologySubject(s)
Chromosome Aberrations , Chromosomes, Human, Pair 5 , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/genetics , Thrombocytopenia/diagnosis , Thrombocytopenia/genetics , Adult , Aged , Aged, 80 and over , Biomarkers/analysis , Blood Platelets/pathology , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Myelodysplastic Syndromes/complications , Myelodysplastic Syndromes/mortality , Platelet Count , Prognosis , Severity of Illness Index , Thrombocytopenia/complications , Thrombocytopenia/mortalityABSTRACT
BACKGROUND/AIMS: Congenital sideroblastic anemias (SA) are characterized by the presence of ringed sideroblasts in the bone marrow. The most common form is X-linked SA, which results from mutations in erythroid-specific δ-aminolevulinate synthase (ALAS2), the first enzyme in heme biosynthesis. In addition, autosomal recessive mutations in the erythroid-specific mitochondrial transporter SLC25A38 and glutaredoxin 5 (GLRX5) have recently been identified in SA patients with isolated erythroid phenotype. MATERIALS AND METHODS: We studied 5 young males with congenital SA from the Czech Republic. Mutation analysis was performed on the complete coding regions of 3 candidate genes (ALAS2, SLC25A38 and GLRX5), and the enzyme activity of ALAS2 was measured by a continuous spectrophotometric assay. RESULTS: We found the previously published R452H and R452C ALAS2 mutations in 3 patients. A novel K156E substitution in ALAS2 was discovered in 1 pyridoxine-responsive patient. The functional study showed that this substitution severely decreases ALAS2 enzyme activity. In 1 pyridoxine-refractory patient, no mutations were detected in ALAS2, SLC25A38 or GLRX5. CONCLUSION: Our report extends the list of known ALAS2 mutations, with the addition of a novel K156E substitution that is responsive to pyridoxine treatment and contributes to the general knowledge of congenital SA cases characterized worldwide.