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Homozygous Haemoglobin C Disease
Hemoglobin C (abbreviated as HbC) is an abnormal hemoglobin in which glutamic acid residue at the 6th position of the β-globin chain is replaced with a lysine residue due to a point mutation in the '' HBB'' gene. People with one copy of the gene for hemoglobin C do not experience symptoms, but can pass the abnormal gene on to their children. Those with two copies of the gene are said to have hemoglobin C disease and can experience mild anemia. It is possible for a person to have both the gene for hemoglobin S (the form associated with sickle cell anemia) and the gene for hemoglobin C; this state is called hemoglobin SC disease, and is generally more severe than hemoglobin C disease, but milder than sickle cell anemia. HbC was discovered by Harvey Itano and James V. Neel in 1950 in two African-American families. It has since been established that it is most common among people in West Africa. It confers survival benefits as individuals with HbC are naturally resistant to malaria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin
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 oxygen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mean Corpuscular Hemoglobin Concentration
The mean corpuscular hemoglobin concentration (MCHC) is a measure of the concentration of hemoglobin in a given volume of packed red blood cell. It is calculated by dividing the hemoglobin by the hematocrit. Reference ranges for blood tests are 32 to 36 g/dL (320 to 360g/L), or between 4.81 and 5.58 mmol/L. It is thus a mass or molar concentration. Still, many instances measure MCHC in percentage (%), as if it were a mass fraction (mHb / mRBC). Definition of MCHCLast Editorial Review: 7/21/1999 Numerically, however, the MCHC in g/dL and the mass fraction of hemoglobin in red blood cells in % are identical, assuming an RBC density of 1g/mL and negligible hemoglobin in plasma. Interpretation A low MCHC can be interpreted as identifying decreased production of hemoglobin. MCHC can be normal even when hemoglobin production is decreased (such as in iron deficiency) due to a calculation artifact. MCHC can be elevated ("polychromatic") in hereditary spherocytosis, sickle cell disease an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemolytic Anemia
Hemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular). This most commonly occurs within the spleen, but also can occur in the reticuloendothelial system or mechanically (prosthetic valve damage). Hemolytic anemia accounts for 5% of all existing anemias. It has numerous possible consequences, ranging from general symptoms to life-threatening systemic effects. The general classification of hemolytic anemia is either intrinsic or extrinsic. Treatment depends on the type and cause of the hemolytic anemia. Symptoms of hemolytic anemia are similar to other forms of anemia ( fatigue and shortness of breath), but in addition, the breakdown of red cells leads to jaundice and increases the risk of particular long-term complications, such as gallstones and pulmonary hypertension. Signs and symptoms Symptoms of hemolytic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygosity
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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-lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythrocytes
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "hollow vessel", with ''-cyte'' translated as "cell" in modern usage), are the most common type of blood cell and the vertebrate's principal means of delivering oxygen (O2) to the body tissues—via blood flow through the circulatory system. RBCs take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries. The cytoplasm of a red blood cell is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin A
Hemoglobin A (HbA), also known as adult hemoglobin, hemoglobin A1 or α2β2, is the most common human hemoglobin tetramer, accounting for over 97% of the total red blood cell hemoglobin. Hemoglobin is an oxygen-binding protein, found in erythrocytes, which transports oxygen from the lungs to the tissues. Hemoglobin A is the most common adult form of hemoglobin and exists as a tetramer containing two alpha subunits and two beta subunits (α2β2). Hemoglobin A2 (HbA2) is a less common adult form of hemoglobin and is composed of two alpha and two delta-globin subunits. This hemoglobin makes up 1-3% of hemoglobin in adults. Structure and function Hemoglobin A (HbA) is the most common adult form of hemoglobin and exists as a tetramer containing two alpha subunits and two beta subunits (α2β2). Each subunit contains a heme group that diatomic oxygen (O2) molecules can bind to. In addition to oxygen, subunit assembly and quaternary structure are known to play important roles in Hb af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotypic Trait
A phenotypic trait, simply trait, or character state is a distinct variant of a phenotypic characteristic of an organism; it may be either inherited or determined environmentally, but typically occurs as a combination of the two.Lawrence, Eleanor (2005) ''Henderson's Dictionary of Biology''. Pearson, Prentice Hall. For example, having eye color is a ''character'' of an organism, while blue, brown and hazel versions of eye colour are ''traits''. The term ''trait'' is generally used in genetics, often to describe phenotypic expression of different combinations of alleles in different individual organisms within a single population, such as the famous purple vs. white flower coloration in Gregor Mendel's pea plants. By contrast, in systematics, the term is ''character state'' is employed to describe features that represent fixed diagnostic differences among taxa, such as the absence of tails in great apes, relative to other primate groups. Definition A phenotypic trait is ... [...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 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] |
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] |
