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Red Cells with High Oxygen Affinity Hemoglobins
Published in Ronald L. Nagel, Genetically Abnormal Red Cells, 2019
This chapter is dedicated to the description of a class of hemoglobin variants that are characterized by an important functional abnormality: their affinity for oxygen is higher than normal. This condition determines that in turn, the red cells of the carriers also have a high affinity for oxygen. According to the intensity of the defect, and probably the genetic makeup of the patient, this high-affinity status of the red cell can be expressed by clinically identifiable erythrocytosis, which involves an increase in the red cell mass beyond the normal range.
Rheology of Polycythemias T. C. Pearson
Published in Gordon D. O. Lowe, Clinical Blood Rheology, 2019
A number of hemoglobin variants with high oxygen affinity have now been described. Characteristically, the oxygen dissociation curve is markedly left-shifted. It is difficult to evaluate the vascular occlusive risk in these patients because the number of individuals affected is small, but the impression is of a lower risk than in patients with PPP. Individual patients with either myocardial ischemia or myocardial infarction have been reported, however.35,36 In the majority of patients with high oxygen affinity hemoglobins, Hb, and PCV values, although elevated, are not very high.37 In a large family in which 20 individuals had Hb Malmö, however, PCV values ranged from 0.46 to 0.65, with 5 individuals having PCV values equal to or above 0.58. Some of these latter patients complained of lightheadedness and fatigue. Two others died suddenly at an early age, but the limitation of assuming that this was related solely to the high PCV due to the hemoglobinopathy is that hypercholesterolemia also occured in some members of the family.37 In a family with Hb Yakima, only one member had a stroke and this individual did not show the presence of the mutant Hb.38
Genetic disorders
Published in Laeth Sari Nasir, Arwa K Abdul-Haq, Caring for Arab Patients, 2018
A recent introduction to the CTGA database is the ability to classify genetic disorders according to their incidence rates in the Arab world. Noteworthy are two groups of disorders: genetic disorders that are highly prevalent and occur at annual incidences (> 100 cases per 100 000 live births). This group encompasses all hemoglobin disorders (thalassemias, sickle cell disease and hemoglobin variants), glucose-6-phosphate dehydrogenase deficiency, Down syndrome, breast cancer, diabetes, anencephaly, Graves disease, Caffey disease, Takayasu arteritis, polycystic kidneys, and other ailments.many other disorders do occur in the Arab world at higher incidence rates when compared to data from the rest of the world. For example: tetralogy of fallot, familial Mediterranean fever, deafness, Noonan syndrome and ankylosing spondylitis. Many of these disorders have been extensively researched and reported in the literature, reflecting their widespread presence in Arab populations. The overwhelming distribution of these diseases in Arabs is best explained by the exposure of Arab countries to common environmental factors that encouraged natural selection for these disorders such as malaria in the case of hemoglobinopathies, and dietary traditions in the case of glucose-6-phosphate dehydrogenase deficiency.
Hb Q-Thailand heterozygosity unlinked with the (–α4.2/) α+-thalassemia deletion allele identified by long-read SMRT sequencing: hematological and molecular analyses
Published in Hematology, 2023
Danqing Qin, Jicheng Wang, Cuize Yao, Xiuqin Bao, Jie Liang, Li Du
Hemoglobinopathies, including thalassemia and hemoglobin variants, are widespread in Asia, especially in Southeast Asia and southern China. Hemoglobin variants are a group of hereditary hemoglobin diseases caused by mutations in globin genes that lead to structural changes in the hemoglobin molecule. To date, more than 1400 hemoglobin variants have been listed in the comprehensive hemoglobin variant database (http://globin.cse.psu.edu./hbvar/menu.html) [1,2]. Among those variants, Hb Q-Thailand [α74(EF3)Asp→His], caused by a missense mutation (GAC > CAC) at codon 74 of the α1-globin gene (HBA1) on chromosome 16p, has occasionally been reported. As one of the most common hemoglobin variants in southern China, Hb Q-Thailand is characterized by an association with a leftward single α2-globin gene (HBA2) deletion (–α4.2/) allele, and to date, no evidence of a single Hb Q-Thailand heterozygote unlinked with the (–α4.2/) allele has been accurately documented [3,4].
Effect of α+ Thalassemia on the Severity of Plasmodium falciparum Malaria in Different Sickle Cell Genotypes in Indian Adults: A Hospital-Based Study
Published in Hemoglobin, 2023
Prasanta Purohit, Pradeep Kumar Mohanty, Jogeswar Panigrahi, Kishalaya Das, Siris Patel
Comparison of complete blood count parameters revealed that there was a significant increase in the total hemoglobin level (p = 0.002) and decreased level of MCV, MCH, and MCHC in patients with α+ thalassemia compared to normal α-globin genotype. Though there was an increased trend in RBC level in patients with α+ thalassemia, it did not reach statistical significance (p ≤ 0.056). The values of WBC, hematocrit and platelet count were at par in all three α-globin genotypes. Comparison of various biochemical parameters showed no significant difference except serum bilirubin total and bilirubin direct, which were decreased in α+ thalassemia groups. LDH value was decreased with decreasing α-globin gene number. Among the hemoglobin variants (HbA0, HbF, and HbA2), HbA2 was only significantly decreased (p < 0.0001) in α+ thalassemia groups. The comparison of hematological and biochemical parameters among the three α-globin genotypes in patients with HbAA genotype is shown in Table 3.
The first Chinese case of unstable Hemoglobin Santa Ana detected by capillary electrophoresis: a case report and literature review
Published in Hematology, 2022
Li Du, Danqing Qin, Jicheng Wang, Cuize Yao, Juan Zhu, Hao Guo, Tenglong Yuan, Jie Liang, Aihua Yin
Hemoglobin variants comprise a group of hereditary hemoglobin diseases caused by mutations in globin genes that lead to structural changes in the hemoglobin molecule. Hemoglobin variants with various clinical manifestations. Unstable hemoglobins are important causes of hemolytic anemia, which is rare and often undiagnosed. Hemoglobin Santa Ana, an unstable hemoglobin variant, was first reported in 1968 [1] and was later confirmed to be due to the HBB gene mutation c.266T > C [2]. In hemoglobin Santa Ana, the amino acid leucine at the 88th position of the normal β-globin chain is replaced by proline, which disturbs not only the heme contact but also the integrity of the F helix [3]. Several patients with hemoglobin Santa Ana have been described, but detection by capillary electrophoresis (CE) has never been reported [1–6]. The clinical manifestations of cases are very similar, including hemolytic anemia, jaundice, brown urine and splenomegaly.