New Cases and Mutations in SEC23B Gene Causing Congenital Dyserythropoietic Anemia Type II

Hereditary anemias; Ineffective erythropoiesis; Rare blood diseaseAnèmies hereditàries; Eritropoesi ineficaç; Malaltia rara de la sangAnemias hereditarias; Eritropoyesis ineficaz; Enfermedad rara de la sangreCongenital dyserythropoietic anemia type II (CDA II) is an inherited autosomal recessive blood disorder which belongs to the wide group of ineffective erythropoiesis conditions. It is characterized by mild to severe normocytic anemia, jaundice, and splenomegaly owing to the hemolytic component. This often leads to liver iron overload and gallstones. CDA II is caused by biallelic mutations in the SEC23B gene. In this study, we report 9 new CDA II cases and identify 16 pathogenic variants, 6 of which are novel. The newly reported variants in SEC23B include three missenses (p.Thr445Arg, p.Tyr579Cys, and p.Arg701His), one frameshift (p.Asp693GlyfsTer2), and two splicing variants (c.1512-2A>G, and the complex intronic variant c.1512-3delinsTT linked to c.1512-16_1512-7delACTCTGGAAT in the same allele). Computational analyses of the missense variants indicated a loss of key residue interactions within the beta sheet and the helical and gelsolin domains, respectively. Analysis of SEC23B protein levels done in patient-derived lymphoblastoid cell lines (LCLs) showed a significant decrease in SEC23B protein expression, in the absence of SEC23A compensation. Reduced SEC23B mRNA expression was only detected in two probands carrying nonsense and frameshift variants; the remaining patients showed either higher gene expression levels or no expression changes at all. The skipping of exons 13 and 14 in the newly reported complex variant c.1512-3delinsTT/c.1512-16_1512-7delACTCTGGAAT results in a shorter protein isoform, as assessed by RT-PCR followed by Sanger sequencing. In this work, we summarize a comprehensive spectrum of SEC23B variants, describe nine new CDA II cases accounting for six previously unreported variants, and discuss innovative therapeutic approaches for CDA II.This work was supported by NEOTEC grant SNEO-20191246 from Spanish CDTI to C.T., RETOS COLABORACION grant RTC2019-007074-1 from: MCIN/AEI/10.13039/501100011033 from Spanish Ministry of Science and Innovation (MICINN) to C.T. and M.S.; ARETHA grant PID2021-122436OB-I00 funded by MCIN/AEI/10.13039/501100011033 to M.S.; RTI-2018-101735-B-I100 from MCIN/AEI/10.13039/501100011033/ERDF “A way to make Europe” from the Spanish Ministry of Science and Innovation (MICINN) to M.S. M.M.M. is supported by a Marie Curie Fellowship from the European Commission under Horizon 2020 Framework Program Project: 894737. G.H. is supported by funds provided by the APU and ADISCON patient associations. L.R.-C. holds an FI-AGAUR predoctoral fellowship (2020FI-B00038) from Generalitat de Catalunya. X.F.-C. is partially supported by funds provided by the grant RTI-2018-101735-B-I100 from MCIN/AEI/10.13039/501100011033/ERDF “A way to make Europe”. V.V. was supported by funds provided by APU and ADISCON patient associations and UIC postdoctoral scholarship; she is currently supported by funds provided by RETOS COLABORACION grant RTC2019-007074-1 from MCIN/AEI/10.13039/501100011033 from Spanish Ministry of Science and Innovation (MICINN)

Incidental finding of rare hemoglobin: hemoglobin Bari in northeast Spain

Hemoglobin BariHemoglobina BariHemoglobina BariObjectives Cation exchange high-performance liquid chromatography (HPLC) is one of the techniques available for determining glycated hemoglobin (HbA1c) and also the method of choice for structural hemoglobinopathies screening. The objective of this case is to show how in a routine HbA1c test it is possible to incidentally find a hemoglobinopathy. Case presentation In a routine blood analysis, an abnormal value for the hemoglobin A2 (HbA2) was obtained during the study of HbA1c with HPLC on the ADAMS™ A1c HA-8180T. After suspecting it could be due to the presence of a hemoglobinopathy, the study of possible variants was expanded using electrophoresis and HPLC on the Hydrasys and Variant II analysers, respectively. Since it could not be identified by these conventional methods, a genetic study was also carried out using Sanger sequencing. The patient presented a low HbA2 (1.3 %) and a 24.9 % variant with a retention time of 1.95 min, compatible with alpha-globin chain variant. In the genetic study, the pathogenic variant c.138C>G was detected in the HbA 2 gene in heterozygosis, which resulted in the expression of the structural hemoglobinopathy known as hemoglobin Bari. Conclusions The initial screening for structural hemoglobinopathies allows its identification or suspicion especially when it was performed with HbA1c analysis, requiring subsequent confirmation and diagnosis by other techniques

International sentinel site surveillance of patients with transfusional hemosiderosis treated with deferasirox in actual practice setting

Funding: This study was funded by Novartis Pharma AGObjective:The study evaluates the long-term deferasirox treatment of adult and pediatricpatients with chronic transfusional iron overload in clinical practice.Methods:In this non-interventional study, patients were observed for up to 3 years frominitiation of deferasirox treatment both prospectively and retrospectively for up to 1 yearprior to enrollment. The primary end points were the proportion of patients with≥1 notableincrease in serum creatinine (SCr), and≥1 notable increase in alanine aminotransferase (ALT).Results:Overall, 120 patients were enrolled and 51 completed the study, with a limited 3-yeardropout rate of 12.5% due to adverse events (AEs). Increase in SCr > 33% above baseline and theage-adjusted ULN (upper limit of normal) was observed in 14 patients (95%CI, 7.1-19.2). The ALTlevels >5 × ULN was observed in 1 patient. Most frequent AEs reported during treatment withdeferasirox include gastrointestinal disturbances.Conclusions:The long-term treatment with deferasirox was manageable in most transfusion-dependent patients with no unexpected safetyfindings. Regular monitoring and an adjusteddeferasirox dosing strategy per local labels allowed continued iron chelation treatment andcontrol of transfusional iron in the majority of patients on study

Hallazgo incidental de una hemoglobina rara: hemoglobina Bari en el noreste de España

Hemoglobina BariHemoglobina Barihemoglobin BariObjetivos La cromatografía líquida de alta resolución (HPLC) es una de las técnicas empleadas para determinar la hemoglobina glicosilada (HbA1c) y el método de elección para el cribado de hemoglobinopatías estructurales. El objetivo de este caso es mostrar cómo en un análisis de rutina de HbA1c es posible encontrar incidentalmente una hemoglobinopatía. Caso clínico En un análisis clínico rutinario, se observó un valor anormal de hemoglobina A2 (HbA2) en el análisis de HbA1c mediante HPLC, realizado con el analizador ADAMS™ A1c HA-8180T. Ante la sospecha de la presencia de una hemoglobinopatía, se amplió el estudio a posibles variantes mediante electroforesis y HPLC, empleando los analizadores Hydrasys y Variant II, respectivamente. Dado que no se pudo identificar con ninguno de los métodos tradicionales, se realizó también un estudio genético mediante secuenciación Sanger. El paciente presentaba niveles bajos de HbA2 (1.3%) y una variante del 24,9% con un tiempo de retención de 1.95 minutos, compatible con una variante de la cadena de alfa-globina. En el estudio genético, se detectó la variante patogénica c.138C>G en el gen HBA2 en heterocigosis, causando la expresión de la hemoglobinopatía conocida como hemoglobina Bari. Conclusiones El cribado inicial de hemoglobinopatías estructurales permite su identificación o suscita sospecha de su presencia, especialmente cuando se realiza junto al análisis de HbA1c, requiriendo posterior confirmación y diagnóstico con otras técnicas

Haemoglobinopathies and other rare anemias in Spain: ten years of a nationwide registry (REHem-AR)

Hemoglobinopathies; Nationwide registry; Rare anaemiasHemoglobinopatías; Registro nacional; Anemias rarasHemoglobinopaties; Registre nacional; Anèmies raresREHem-AR was created in 2013. The progressive implementation of neonatal screening for haemoglobinopathies in Spanish autonomous communities where the registry had not been implemented, as well as the addition of new centres during this period, has considerably increased the sample of patients covered. In this study, we update our previous publication in this area, after a follow-up of more than 5 years. An observational, descriptive, multicentre and ambispective study of adult and paediatric patients with haemoglobinopathies and rare anaemias registered in REHem was performed. The data are from a cross-sectional analysis performed on 1 June, 2023. The study population comprised 1,756 patients, of whom 1,317 had SCD, 214 had thalassaemia and 224 were diagnosed with another condition. Slightly more than one third of SCD patients (37%) were diagnosed based on neonatal bloodspot screening, and the mean age at diagnosis was 2.5 years; 71% of thalassaemia patients were diagnosed based on the presence of anaemia. Vaso-occlusive crisis and acute chest syndrome continue to be the most frequent complications in SCD. HSCT was performed in 83 patients with SCD and in 50 patients with thalassaemia. Since the previous publication, REHem-AR has grown in size by more than 500 cases. SCD and TM are less frequent in Spain than in other European countries, although the data show that rare anaemias are frequent within rare diseases. REHem-AR constitutes an important structure for following the natural history of rare anaemias and enables us to calculate investment needs for current and future treatments.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. JM.M.S employment contract has been partially funded by a research grant from Novartis

Combining microfluidics with machine learning algorithms for RBC classification in rare hereditary hemolytic anemia

Combining microfuidics technology with machine learning represents an innovative approach to conduct massive quantitative cell behavior study and implement smart decision-making systems in support of clinical diagnostics. The spleen plays a key-role in rare hereditary hemolytic anemia (RHHA), being the organ responsible for the premature removal of defective red blood cells (RBCs). The goal is to adapt the physiological spleen fltering strategy for in vitro study and monitoring of blood diseases through RBCs shape analysis. Then, a microfuidic device mimicking the slits of the spleen red pulp area and video data analysis are combined for the characterization of RBCs in RHHA. This microfuidic unit is designed to evaluate RBC deformability by maintaining them fxed in planar orientation, allowing the visual inspection of RBC's capacity to restore their original shape after crossing microconstrictions. Then, two cooperative learning approaches are used for the analysis: the majority voting scheme, in which the most voted label for all the cell images is the class assigned to the entire video; and the maximum sum of scores to decide the maximally scored class to assign. The proposed platform shows the capability to discriminate healthy controls and patients with an average efciency of 91%, but also to distinguish between RHHA subtypes, with an efciency of 82%

Usefulness of NGS for Diagnosis of Dominant Beta-Thalassemia and Unstable Hemoglobinopathies in Five Clinical Cases

Seqüenciació de nova generació; Trastorns d’anèmia rars; Hemoglobinopaties inestablesNext generation sequencing; Rare anemia disorders; Unstable hemoglobinopathiesSecuenciación de nueva generación; Trastornos raros de la anemia; Hemoglobinopatías inestablesUnstable hemoglobinopathies (UHs) are rare anemia disorders (RADs) characterized by abnormal hemoglobin (Hb) variants with decreased stability. UHs are therefore easily precipitating, causing hemolysis and, in some cases, leading to dominant beta-thalassemia (dBTHAL). The clinical picture of UHs is highly heterogeneous, inheritance pattern is dominant, instead of recessive as in more prevalent major Hb syndromes, and may occur de novo. Most cases of UHs are not detected by conventional testing, therefore diagnosis requires a high index of suspicion of the treating physician. Here, we highlight the importance of next generation sequencing (NGS) methodologies for the diagnosis of patients with dBTHAL and other less severe UH variants. We present five unrelated clinical cases referred with chronic hemolytic anemia, three of them with severe blood transfusion dependent anemia. Targeted NGS analysis was performed in three cases while whole exome sequencing (WES) analysis was performed in two cases. Five different UH variants were identified correlating with patients’ clinical manifestations. Four variants were related to the beta-globin gene (Hb Bristol—Alesha, Hb Debrousse, Hb Zunyi, and the novel Hb Mokum) meanwhile one case was caused by a mutation in the alpha-globin gene leading to Hb Evans. Inclusion of alpha and beta-globin genes in routine NGS approaches for RADs has to be considered to improve diagnosis’ efficiency of RAD due to UHs. Reducing misdiagnoses and underdiagnoses of UH variants, especially of the severe forms leading to dBTHAL would also facilitate the early start of intensive or curative treatments for these patients.This study was supported by funding from the authors’ institutions and the European Commission H2020-MSCA-ITN-2019, Grant Agreement N860436, “EVIDENCE.

Incidental finding of rare hemoglobin: hemoglobin Bari in northeast Spain

Cation exchange high-performance liquid chromatography (HPLC) is one of the techniques available for determining glycated hemoglobin (HbA1c) and also the method of choice for structural hemoglobinopathies screening. The objective of this case is to show how in a routine HbA1c test it is possible to incidentally find a hemoglobinopathy