Hemoglobin最新文献

The commonly used methods for HbA1c measurement are cation-exchange high performance chromatography (CE-HPLC), immunologic method, capillary electrophoresis and boronate affinity HPLC. Hb-variants can reduce the reliability of HbA1c measurements. We aimed to emphasize the importance of step-by-step solutions to the difficulties encountered in HbA1c measurement methods due to Hb-variants. We also aimed to evaluate the advantages and disadvantages of different methods used in HbA1c analysis with the example of the Hb-Iraq-Halabja variant detected for the first time in Türkiye. HbA1c level could not be measured by CE-HPLC (Adams HA-8180V analyzer, Arkray, Japan) and a peak-tailing signal was detected indicating an abnormality between stable HbA1c and HbA0 peaks (concurrent glucose level was 8.55mmol/L). In the second step, HbA1c was able to be measured by immunologic method and boronate affinity method and were found to be 5.87% and 5.90%, respectively (estimated average glucose equivalent 6.66mmol/L). In the last step, genetic analysis was performed due to suspicion of Hb variant and the very rare Hb Iraq-Halabja variant was detected. After genetic verification, HbA1c test was repeated with a different CE-HPLC (HLC-723 G11, T osoh, Tokyo, Japan) and a peak indicating variant Hb was detected between stable HbA1c and HbA0. A remarkable finding was that, unlike the previous CE-HPLC (Arkray) result, HbA1c could be measured as 3.20%. In the concurrent measurement performed on the boronate affinity HPLC (Premier Hb9210, Trinity Biotech, County Wicklow, Ireland), HbA1c result was found to be 5.40% (concurrent glucose 5.22 mmol/L). In addition, concurrent fructosamine serum value was found to be 210 μmol/L (estimated mean glucose equivalent 4.88 mmol/L). The patient's laboratory tests were generally within normal limits, and iron deficiency, hemolytic anemia, and B12-folate deficiency were excluded. The glucose bounding area of hemoglobin is generally preserved and is not affected by common Hb-variants. Boronate affinity and immunologic method (these two methods target glucose bounding areas) that give HbA1c results consistent with the patient's fasting blood glucose and fructosamine results. However, the CE-HPLC method has been observed to either fail to measure HbA1c or to measure falsely low HbA1c due to overlapping peaks of Hb variants.

Backgound: Induction of fetal hemoglobin (HbF; α2γ2) production can alleviate the clinical severity of sickle cell disease (SCD) and β-thalassemia. KLF1 SNPs (e.g. rs2072597) correlate with elevated fetal hemoglobin levels in HPFH patients. Some studies suggest that KLF1 may indirectly suppress γ-globin expression by regulating the KLF1-dependent transcriptional repressor BCL11A or directly activate γ-globin. This study aims to investigate the effect of KLF1 on the γ-globin gene.

Material/methods: KLF1 was downregulated in K562 cells via RNAi, with optimized shRNA delivered by lentivirus. Additionally, an in vitro erythropoiesis model using β-thalassemia major-derived mononuclear cells (MNCs) assessed γ-globin expression. γ-globin levels were quantified by RT-qPCR and Western blot (K562) or RT-qPCR alone (erythroblasts).

Results: Knockdown of KLF1 in K562 cells significantly suppressed γ-globin expression and elevated the γ/α globin mRNA ratio in human erythrocytes, concurrent with disrupted erythroid maturation. KLF2 expression was upregulated under KLF1-deficient conditions.

Conclusions: KLF1 exhibits dual, context-dependent regulation of globin genes, acting as both activator and repressor. These findings suggest that pharmacological targeting of KLF1 may not be an optimal therapeutic strategy for β-hemoglobinopathies.

HBA2: c.70G > A (Hb Chad) and HBA1: c.84G > T (Hb Hekinan II) are extremely rare α-globin chain variants, while HBB: c.-78A > G is a relatively common mutation in β-thalassemia. This study aims to identify potential hemoglobin variants in a 12-year-old Chinese boy (proband) and evaluate the presence of thalassemia trait in his parents. We used an automated blood cell analyzer to obtain hematological data, capillary zone electrophoresis to analyze hemoglobin, and sequencing of α-globin and β-globin genes for molecular characterization. The proband exhibited typical thalassemia traits, with hemoglobin electrophoresis suggesting a complex α- and β-chain hemoglobinopathy. Genetic testing revealed that the proband was a double heterozygote for HBA2: c.70G > A (Hb Chad) and HBB: c.-78A > G, while the proband's mother was a compound heterozygote for HBA2: c.70G > A (Hb Chad) and HBA1: c.84G > T (Hb Hekinan II). This study reports for the first time two novel cases of hemoglobinopathy in a Chinese family, involving HBA2: c.70G > A (Hb Chad)/HBB: c.-78A > G and HBA2: c.70G > A (Hb Chad)/HBA1: c.84G > T (Hb Hekinan II).

Here we report a hemoglobin (Hb) variant, initially detected by matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS). A 29-year-old woman who presented to our hospital for a medical examination showed a remarkable discrepancy between her fasting plasma glucose level (5.07 mmol/L) and her HbA_1c value (3.61%), as determined by capillary electrophoresis (CE). Hemoglobin analysis by MALDI TOF MS revealed an abnormal globin with a mass of 15853 Da. Sanger sequencing identified a novel missense mutation in exon 112 of the β-globin chain [CD 112(G14) Cys > Ser (TGT > TCT); HBB:c.338G > C]. In reference to the birthplace of the proband, this variant was named Hb Jiangxi.

A 31-year-old pregnant African woman presents to our unit following hemoglobin-HPLC analysis, which reveals a slightly elevated HbF fraction (4.2%). Molecular analysis of the α and β-globin genes did not detect any mutations. To further investigate her persistent fetal hemoglobin (HPFH), we performed Sanger sequencing of the γ-globin promoter. This analysis uncovered two unknow point mutations: HBG1: c.-305 A > G and HBG2: c.-309 A > G. Notably, the mutation in the ^Aγ-globin promoter lies within the AGGAA binding site of the C2H2 zinc finger transcription factor IZKF1. This mutation may account for the patient's HPFH and highlights the importance of analyzing all promoter binding sites in genome editing-based therapies for β-thalassemia.

MCS-R regulatory elements are very important for the synthesis of α-globin. Deletion of the major α-globin regulatory elements compounded with deletion of α-globin genes can cause Hb Bart's (c4) hydrops fetalis, which is the severe form of α-thalassemia. In this report, a 19-year-old female at the 16th week of gestation came to our center due to abnormal fetal cardiothoracic ratio and thickened placental depth. The electrophoresis result of fetal umbilical cord blood revealed the level of Hb Bart's band to be 87.6%, which suggested the fetus was Hb Bart's hydrops fetalis. Next generation sequencing screen using targeted capture was used to detect the genotype of the fetus to be -SEA deletion, βA/βA. Multiplex ligation-dependent probe amplification (MLPA) is very useful to detect copy number variation (deletions/duplications), the result of which suggested the existence of -SEA deletion compounded with the novel large deletion of the major α-globin regulatory element (MCS-R2, R1, R3 and R4). Using the self-designed MLPA probe, the deletion should extend from the telomere downstream and the downstream breakpoint was between 143702 and 144291(GRch38/hg18). The novel deletion was also observed in the fetus' father and grandfather who had mild anemia. Of cases with the MCS deletion compounded with α⁰-thalassemia, this was the earliest time when the fetus presented fetal edema. Our study gave more evidence for genetic counseling for MCS deletion.

Thalassemia is one of the most prevalent genetic disorders. Blood transfusion, as the main treatment, harbors diverse side effects, including alloimmunization to RBC antigens, exacerbating hemolysis, and blood requirements. The role of miR155, as a regulator of the immune system, was investigated to divulge its role in the production of alloantibodies in thalassemia patients. The antibody screening technique was used to identify TDT patients with alloimmunization against erythrocyte antigens. PBMC were isolated from selected TDT patients and matched controls using the Ficoll-Paque method, and then miRNA was extracted from cells by the TRIzol reagent. Finally, the relative expression of miR155 was measured using the stem-loop RT-PCR technique. One hundred fifty-eight patients with TDT were screened for the presence of alloantibodies, of whom 14 patients were identified to develop alloimmunization against RBC antigens. There was no statistically significant difference between TDT patients with or without alloantibodies (15 age and sex matched non-immunized patients) in terms of the frequencies of splenectomy, vaccination against hepatitis B, blood types, RHD positivity, and various complications. The expression of miR155 was significantly higher in patients with alloantibodies (mean fold change: 4.74 ± 2.76) compared to non-immunized TDT patients (mean fold change: 1.8 ± 0.68, P = 0.002). Our findings indicated that miR155 overexpression can be involved in modulating immune responses and triggering the production of alloantibodies in TDT patients. More studies are required in this field to further elucidate the role of miR155 in alloimmunization of these patients and other conditions associated with this problem.

Heterozygous β-thalassemia is typically asymptomatic, but when accompanied by α-globin gene multiplication, patients may exhibit clinical symptoms. We present two rare cases of heterozygous β-thalassemia where segmental duplications on chr16p13.3 led to increased α-globin gene copies, resulting in a thalassemia intermedia phenotype. One patient exhibited a novel de-novo duplication spanning 2.57 MB, while the other had a 173.8 KB duplication at the chr16p13.3 locus. These two cases are presented to underscore the significance of thorough and systematic evaluation in diagnosing rare forms of thalassemia accurately. Our study also compiles all reported cases of heterozygous β-thalassemia with large segmental duplications on chr16p13.3, leading to an excess of α-globin genes. A total of ten studies have been published in the literature so far. Importantly, the 2.57 MB segmental duplication identified in our study is a novel variant not previously documented in the literature.