Hemoglobin最新文献

Hemoglobin (Hb) Chile, a variant of Hb M, is produced by a point mutation of CTG→ATG on codon 29 (legacy codon 28) of the Hb β locus gene, which results in an amino acid substitution of Leu→Met. It has been identified in two families worldwide and is inherited in an autosomal dominant manner. Here, we report a case of Hb Chile in which a de novo mutation was detected in the proband. A 17-year-old male presented to the outpatient clinic with a pale appearance. There was cyanosis on his lips and fingers. Blood tests indicated the existence of hemolysis, but complete blood counts revealed no anemia. Peripheral arterial oxygen saturation on pulse oximetry was 80% on room air and did not improve with oxygen supplementation. The level of methemoglobin was 15.4%. Targeted next-generation sequencing identified a heterozygous NM_000518.4(HBB):c.85C > A mutation, indicating Hb Chile. The Hb Chile mutation, on the other hand, was not discovered in his parents, implying that it arose as a result of a de novo mutation. This case highlights the necessity of suspecting Hb gene mutations in patients with unexplained chronic methemoglobinemia, even if there is no family history.

Hemoglobin (Hb) Malay is a common β hemoglobinopathy in Malaysia caused by A > G mutation in codon 19 leading to β+-thalassemia phenotype. However, screening for Hb Malay is challenging as it is undetectable by routine capillary electrophoresis (CE) or high-performance liquid chromatograpy (HPLC) methods. This study aimed to determine the Hb Malay phenotypes. The study was done on 521 cases with presumed β thalassemia from UKMMC and Hospital Selayang as well as confirmed Hb Malay cases from Hospital Sultanah Bahiyah, Kedah in over a 5-year period. Hb analysis using CE or HPLC followed by multiplex amplification refractory mutation system polymerase chain reaction and DNA sequencing were performed. Significant differences in mean values of haematological parameters among Hb Malay carriers against β thalassemia carriers were determined using one-way ANOVA and ROC analysis. A total of 482/521 cases of β globin mutations were identified. Among these, 54 Hb Malay cases were identified whereby 21 Hb Malay cases were from UKMMC and Hospital Selayang whilst 33 Hb Malay cases were from Hospital Sultanah Bahiyah, Kedah. Fifty-two were Hb Malay carriers whereas two cases were compound heterozygotes. The mean hemoglobin, mean cell volume, mean cell hemoglobin, and HbA of Hb Malay carriers were significantly higher than β° thalassemia carriers. The HbA₂ range of Hb Malay carriers was wider (3.5-5.5%) with median value of 3.9%. A new HbA₂ cutoff value ≤4.6% (AUC 0.717, p < 0.001) was proposed. Compound heterozygous Hb Malay/IVS1-5(G > C) showed transfusion-dependent thalassemia phenotype. Hb Malay carriers have different red cell and electrophoretic parameters than classical β° thalassemia carriers with wider HbA₂ range. HbA₂ of ≤4.6% should prompt a molecular confirmation for Hb Malay carrier status.

In order to document the prevalence, clinical features, hematology and outcome of the aplastic crisis in homozygous sickle cell disease (HbSS), a cohort study has been conducted from birth. Newborn screening of 100 000 deliveries at the main government maternity hospital, Kingston, Jamaica between 1973 and 1981 detected 311 cases of HbSS who have been followed at the Medical Research Council Laboratories at the University of the West Indies, Kingston, Jamaica. Clinically defined aplastic crises occurred in 118 (38%) patients at a median age of 7.5 years (range 0.5-23.0 years). All but one event seroconverted to parvovirus B19, the exception being a 9.3 year male with classic aplasia but subsequent IgG did not exceed 3 IU. Defined by zero reticulocyte counts, 94 patients presented with a median hemoglobin of 3.7 g/dL (range 18-87 g/L) representing a median fall from steady state levels of 3.8 g/dL. Clear epidemic peaks occurred at 1979-1980, 1984-1986, and 1990-1993 and the admission rate and use of blood cultures fell with each epidemic, reflecting increased familiarity with the complication. Symptoms were usually nonspecific and all but 7 were transfused. No patient had a recurrence and two died from aplasia (one with remote rural residence and the other following an incorrect diagnosis). Of those seroconverting to parvovirus B19, 68% manifested aplasia and 24% had no hematologic change. Correctly diagnosed and managed, the aplastic crisis is essentially benign. (230 words).

Graft rejection and Graft-versus-host disease (GVHD) are some of the significant factors resulting in morbidity and mortality following allogeneic hematopoietic cell transplantation. Prophylaxis for GVHD using T-cell depleting agents is helpful in reducing the transplant-related mortality and graft rejection. Both tATG and fATG exhibit varied amounts of antibody specificities and perform distinct immunomodulatory effects, regardless of their capacity to deplete T-lymphocytes. We conducted this single-center, retrospective study at our center to compare both formulations. Twenty-six patients were included in the study, 13 in each cohort. The median age at diagnosis of β-thalassemia was 5 months (range, 3-12 months) in the tATG group and 6 months (range, 3-9 months) in the f-ATG group, respectively. Acute GVHD was observed in 1 (7.7) and 2(15.4) in the tATG and fATG group, respectively. No cases of chronic GVHD were observed in either group. There was no difference in the mixed chimerism observed at 6 months in both groups, tATG (n = 5, 38.5%) and fATG (n = 6, 46.15). There was 1 (7.6) rejection at day +72 observed in the tATG group, whereas no rejection was observed in the fATG group. At a mean follow-up duration of 288 days since transplant, there were no deaths in either of the groups. In conclusion, both ATG preparations showed equivalent effectiveness in preventing rejections and GVHD. However, further larger studies are required to establish the long-term efficacy and safety of both formulations in ASCT.

Hb Youngstown [HBB:c.305A > C] is a rare unstable hemoglobin caused by the substitution of glutamic acid with alanine at codon 101 of the Beta globin chain. It causes hemolytic anemia in the heterozygous state. This is a case of a six-year-old Chinese-Javanese girl with heterozygous Hb Youngstown and clinical features of chronic hemolysis and iron overload. Hb Youngstown appears at the S window near to 4.6 minutes on high-performance liquid chromatography (HPLC) and can form a hybrid tetramer on alkaline gel electrophoresis seen as two distinct bands cathodal to A and close to F. For the first time, Hb Youngstown is captured with capillary electrophoresis (CE) and shown to be eluted at zone 8. Clinical presentation and Hb analysis results of this heterozygous Hb Youngstown overlap with heterozygous Hb Rush. They can only be differentiated at molecular level by Beta globin gene sequencing or intact mass spectrometry.

Hemoglobin (Hb) H disease presents a wide range of clinical phenotypes, from asymptomatic to severe forms, depending on significant genetic heterogeneity. This is the first report of clinical and hematological features of the nondeletional HbH disease caused by --^CR/α^CSα. A baby was born to a father and a mother with --^CR and α^CSα carriers, respectively. She had severe symptomatic hypochromic microcytic anemia at 2 months of age with Hb 7.8 g/dL, packed cell volume (PCV) 0.27 L/L, mean corpuscular volume (MCV) 64.3 fL, and mean corpuscular Hb (MCH) 18.3 pg. The Hb analysis using capillary electrophoresis (CE) showed Hb Bart's, HbH, and Hb CS peaks at 17.1%, 2.2%, and 1.6%, respectively. A better understanding of a patient's clinical and hematological features with --^CR/α^CSα is useful for hemoglobinopathy counseling for the national thalassemia controlling program.

We report the molecular and hematological identifications of two novel δ-globin gene mutations found in Guangxi Zhuang Autonomous Region, China. Capillary electrophoresis of the proband showed 1.3% Hb A₂, accompanied by a minor unknown peak (0.7%) within the Z1 zone. High-performance liquid chromatography also revealed the presence of 1.5% Hb A₂ and a 0.6% unknown peak. Routine genetic testing (Gap-PCR and reverse dot-blot hybridization) for common α-thalassemia was performed, and no mutations were observed. Sanger sequencing identified a heterozygous mutation for GAC > AAC at codon 79 (HBD:c.238G > A) and G > A at polyA + 70 (HBD:c.*200G > A) of the δ-globin gene. This variant was named Hb A₂-Guangxi [δ79 (EF3) Asp→Asn, HBD:c.238G > A] after the geographic origin of the proband.

Due to the significant morbidity and mortality of hemoglobinopathies, curative options have long been pursued. The overall goal of gene therapy is to modify a patient's own hematopoietic stem cells to overcome the deleterious effects of the underlying genetic defect by gene addition, gene editing, or gene silencing. Gene addition incorporates genes with superior function than the abnormal gene; gene editing takes advantage of molecular tools such as zinc finger proteins, Transcription Activator-Like Effector Nucleases and Clustered Regularly Interspaced Short Palindromic Repeats coupled with Cas9 proteins (CRISPR-Cas9) which allow for sequence-specific breaks in DNA that disrupt gene function; and gene silencing suppresses gene expression by interference with mRNA transcription/protein translation or epigenetic modification. The majority of gene therapy strategies for hemoglobinopathies have targeted erythroid-specific BCL11A, a major regulator of fetal hemoglobin repression at the gamma-globin locus, in the normal fetal-to-adult hemoglobin switch that occurs shortly after birth. Other goals have involved the incorporation of anti-sickling globins, such as β^T87Q or βAS3. Landmark clinical trials of gene therapy in transfusion-dependent thalassemia and sickle cell disease have shown remarkable efficacy and acceptable safety and culminated in recent regulatory approvals of gene therapy for both diseases in Europe and the United States.

Hemoglobin Strasbourg is a rare high oxygen affinity hemoglobin variant which leads to secondary erythrocytosis. This variant is caused by a HBB gene mutation c.71T > A resulting in an amino acid exchange on position 23 of the β globin chain (p.Val23Asp.). The influence of Hb Strasbourg on HbA1c measurement has not been studied to date. For patients with hemoglobin variants it is important to know whether possible interferences exist with the measurement of HbA1c. We therefore investigated the influence of Hb Strasbourg on HbA1c measurement with two different HPLC (high-performance liquid chromatography) systems and one turbidimetric immunoassay in two non-diabetic brothers who are heterozygous carriers of Hb Strasbourg. The examined tests are all used in routine diagnostics. In the case of Hb Strasbourg, the HbA1c measured by HPLC showed lower results than those obtained by the immunoassay. We conclude that HbA1c is underestimated when measured with these methods as glycated Hb Strasbourg is most likely not co-eluting with HbA1c in HPLC.

We reported a rare β-thalassemia patient, a 41-year-old Chinese male with small cell hypopigmentation anemia, jaundice and splenomegaly as the main clinical symptoms. By using Next-Generation Sequencing (NGS), we identified a novel de novo HBB mutation(c.358_365dup, p.Phe123Alafs*39) which resulted in an abnormally prolonged β-globin chain comprising 159 amino acid residues. The secondary and three-dimensional structures of the β-globin predicted that the novel prolonged β-globin chain has a considerable risk of instability in the hemoglobin, and leads to clinical phenotype. This study contributes to the enrichment of the genetic pathogenic mutation database for thalassemia and underscores the significance of NGS in the screening of mutations for thalassemia families.