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Haemoglobinopathies
Hemoglobinopathy is the medical term for a group of inherited blood disorders and diseases that primarily affect red blood cells. They are single-gene disorders and, in most cases, they are inherited as autosomal co-dominant traits. There are two main groups: abnormal structural hemoglobin variants caused by mutations in the hemoglobin genes, and the thalassemias, which are caused by an underproduction of otherwise normal hemoglobin molecules. The main structural hemoglobin variants are HbS, HbE and HbC. The main types of thalassemia are alpha-thalassemia and beta thalassemia. The two conditions may overlap because some conditions which cause abnormalities in hemoglobin proteins also affect their production. Some hemoglobin variants do not cause pathology or anemia, and thus are often not classed as hemoglobinopathies. Hemoglobin structural biology Normal human hemoglobins are tetrameric proteins composed of two pairs of globin chains, each of which contains one alpha-like ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sickle Cell Disease
Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. This leads to a rigid, sickle-like shape under certain circumstances. Problems in sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain (known as a sickle cell crisis), anemia, swelling in the hands and feet, bacterial infections and stroke. Long-term pain may develop as people get older. The average life expectancy in the developed world is 40 to 60 years. Sickle cell disease occurs when a person inherits two abnormal copies of the β-globin gene (''HBB'') that makes haemoglobin, one from each parent. This gene occurs in chromosome 11. Several subtypes exist, depending on the exact mutation in each haemoglobin gene. An attack can be set off by tempera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin Lepore
Hemoglobin Lepore syndrome is typically an asymptomatic hemoglobinopathy, which is caused by an autosomal recessive genetic mutation. The Hb Lepore variant, consisting of two normal alpha globin chains (HBA) and two delta-beta globin fusion chains which occurs due to a "crossover" between the delta (HBD) and beta globin (HBB) gene loci during meiosis and was first identified in the Lepore family, an Italian-American family, in 1958. There are three varieties of Hb Lepore, Washington (Hb Lepore Washington, AKA Hb Lepore Boston or Hb Lepore Washington-Boston), Baltimore (Hb Lepore Baltimore) and Hollandia (Hb Hollandia). All three varieties show similar electrophoretic and chromatographic properties and hematological findings bear close resemblance to those of the beta-thalassemia trait; a blood disorder that reduces the production of the iron-containing protein hemoglobin which carries oxygen to cells and which may cause anemia. The homozygous state for Hb Lepore is rare. Patie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sickle Cell Anemia
Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. This leads to a rigid, sickle-like shape under certain circumstances. Problems in sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain (known as a sickle cell crisis), anemia, swelling in the hands and feet, bacterial infections and stroke. Long-term pain may develop as people get older. The average life expectancy in the developed world is 40 to 60 years. Sickle cell disease occurs when a person inherits two abnormal copies of the β-globin gene (''HBB'') that makes haemoglobin, one from each parent. This gene occurs in chromosome 11. Several subtypes exist, depending on the exact mutation in each haemoglobin gene. An attack can be set off by tempera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Thalassemia
Beta thalassemias (β thalassemias) are a group of inherited blood disorders. They are forms of thalassemia caused by reduced or absent synthesis of the beta chains of hemoglobin that result in variable outcomes ranging from severe anemia to clinically asymptomatic individuals. Global annual incidence is estimated at one in 100,000. Beta thalassemias occur due to malfunctions in the hemoglobin subunit beta or HBB. The severity of the disease depends on the nature of the mutation. HBB blockage over time leads to decreased beta-chain synthesis. The body's inability to construct new beta-chains leads to the underproduction of HbA (adult hemoglobin). Reductions in HbA available overall to fill the red blood cells in turn leads to microcytic anemia. Microcytic anemia ultimately develops in respect to inadequate HBB protein for sufficient red blood cell functioning. Due to this factor, the patient may require blood transfusions to make up for the blockage in the beta-chains. Repeated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin S
Sickle cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as sickle cell anaemia. It results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. This leads to a rigid, sickle-like shape under certain circumstances. Problems in sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain (known as a sickle cell crisis), anemia, swelling in the hands and feet, bacterial infections and stroke. Long-term pain may develop as people get older. The average life expectancy in the developed world is 40 to 60 years. Sickle cell disease occurs when a person inherits two abnormal copies of the β-globin gene (''HBB'') that makes haemoglobin, one from each parent. This gene occurs in chromosome 11. Several subtypes exist, depending on the exact mutation in each haemoglobin gene. An attack can be set off by tempera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin O-Arab
Hemoglobin O-Arab (American English) or Haemoglobin O-Arab (British English) is a rare alternation of Hemoglobin (American English) or Haemoglobin (British English), characterised with the presence of β^121Glu → Lys (Hb O-Arab). Mutations of heterozygotes for Hb O-Arab have been reported in Saudi Arabia, North Africa, Sudan, the Mediterranean and the United States. Diagnosis of Hb O-Arab requires liquid chromatography on both cellulose acetate and citrate agar, due to co-migrating with Hb C at acidic pH. When combined with Hemoglobin S (β^6Glu → Val) it causes a severe form of Sickle cell disease known as Hemoglobin S/O-Arab. Detection of Hb O-Arab can be carried out with a blood test, identifying the carries of hemoglobinopathies, so as to inform patients their chances of producing an affected child and ensure appropriate guidance is given. Research History Although the molecular structure of hemoglobin itself has been determined by molecular biologist, Max Perutz, by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin E
Hemoglobin E (HbE) is an abnormal hemoglobin with a single point mutation in the β chain. At position 26 there is a change in the amino acid, from glutamic acid to lysine (E26K). Hemoglobin E is very common among people of Southeast Asian, Northeast Indian, Sri Lankan and Bangladeshi descent. The βE mutation affects β-gene expression creating an alternate splicing site in the mRNA at codons 25-27 of the β-globin gene. Through this mechanism, there is a mild deficiency in normal β mRNA and production of small amounts of anomalous β mRNA. The reduced synthesis of β chain may cause β-thalassemia. Also, this hemoglobin variant has a weak union between α- and β-globin, causing instability when there is a high amount of oxidant. HbE can be detected on electrophoresis. Hemoglobin E disease (EE) Hemoglobin E disease results when the offspring inherits the gene for HbE from both parents. At birth, babies homozygous for the hemoglobin E allele do not present symptoms because they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin Barts
Hemoglobin Barts, abbreviated Hb Barts, is an abnormal type of hemoglobin that consists of four gamma globins. It is moderately insoluble, and therefore accumulates in the red blood cells. Hb Barts has an extremely high affinity for oxygen, so it cannot release oxygen to the tissue. Therefore, this makes it an inefficient oxygen carrier. As an embryo develops, it begins to produce alpha-globins at weeks 5–6 of development. When both of the HBA1 and HBA2 genes which code for alpha globins becomes dysfunctional, the affected fetuses will have difficulty in synthesizing a functional hemoglobin. As a result, gamma chains will accumulate and form four gamma globins. These gamma globins bind to form hemoglobin Barts. It is produced in the disease alpha-thalassemia and in the most severe of cases, it is the only form of hemoglobin in circulation. In this situation, a fetus will develop hydrops fetalis and normally die before or shortly after birth, unless intrauterine blood transfusion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin D
Within the medical specialty of hematology, Hemoglobin D-Punjab is one of the sub-variants of Hemoglobin D, a variant of hemoglobin found in human blood. It is so named because of its higher prevalence in the Punjab region of India and Pakistan. It is also the most frequent abnormal hemoglobin variant in Xinjiang Uyghur Autonomous Region of China. Studies indicate that Hemoglobin D-Punjab accounts for over 55% of the total hemoglobin variants there. Hemoglobin D is a result of a mutation in the one or both of the Beta-chains that make up hemoglobin molecules. Having one gene effected is referred to as trait; having two is referred to as homozygous "disease" although the symptoms of this disease are mild. Hemoglobin D-Punjab was first discovered in the early 1950s in a mixed British and American family of Indian origin from the Los Angeles area; hence it is also sometimes called “D Los Angeles”. Hemoglobin D is the 4th most common hemoglobin variant. It developed as a respon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin O
Hemoglobin O (HbO) is a rare type of hemoglobin in which there is a substitution of glutamic acid by lysine as in hemoglobin C, but at different positions. Since the amino acid substitution can occur at different positions of the HBB, β-globin chain of the protein, there are several variants. In hemoglobin O-Arab (HbO-Arab) substitution occurs at position 121, while in hemoglobin O-Padova (HbO-Padova) it is at 11 position, and in hemoglobin O Indonesia (HbOIna) it is at 116. HbO is usually harmless unlike other hemoglobin variants such as Sickle cell disease, HbS and thalassemias, even under combination with these abnormal hemoglobins. Hemoglobin O-Padova is the most severe form and is associated with disease of the RBCs and spleen. __TOC__ Discovery Hemoglobin O Indonesia is the first discovered HbO. Lie-Injo Luan Eng at the University of Indonesia, Djakarta, was the first to notice the abnormal hemoglobin in 1956 among the Buginese people of Sulawesi Island in Indonesia. It was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin Constant Spring
Hemoglobin Constant Spring is a variant of hemoglobin in which a mutation in the alpha globin gene produces an alpha globin chain that is abnormally long. It is the most common nondeletional alpha-thalassemia mutation associated with hemoglobin H disease. The quantity of hemoglobin in the cells is low because the messenger RNA is unstable and some is degraded prior to protein synthesis. Another reason is that the Constant Spring alpha chain protein is itself unstable. The result is a thalassemic phenotype. Hemoglobin Constant Spring is renamed after Constant Spring district in Jamaica. See also * Hemoglobin variants * Hemoglobinopathy Hemoglobinopathy is the medical term for a group of inherited blood disorders and diseases that primarily affect red blood cells. They are single-gene disorders and, in most cases, they are inherited as autosomal co-dominant traits. There are t ... * Thalassemia References {{Reflist Hemoglobins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin G
Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocytes) of almost all vertebrates (the exception being the fish family Channichthyidae) as well as the tissues of some invertebrates. Hemoglobin in blood carries oxygen from the respiratory organs (''e.g.'' lungs or gills) to the rest of the body (''i.e.'' tissues). There it releases the oxygen to permit aerobic respiration to provide energy to power functions of an organism in the process called metabolism. A healthy individual human has 12to 20grams of hemoglobin in every 100mL of blood. In mammals, the chromoprotein makes up about 96% of the red blood cells' dry content (by weight), and around 35% of the total content (including water). Hemoglobin has an oxygen-binding capacity of 1.34mL O2 per gram, which increases the total blood oxyge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
