Beta thalassemia is a hereditary hemolytic anemia caused by a defect in the ability of erythroblasts to synthesize the. Like all common globin gene disorders sickle cell trait and. Alpha thalassemia intermedia, or hemoglobin h disease, causes hemolytic anemia. Your body makes less of the beta chains, but is still able to make plenty of. Beta thalassemia is often classified into three types.
The clinical manifestations include hemolytic anemia and impaired iron handling, the severity of which depends on the degree of impairment in beta. Anemia occurs when your body does not have enough red blood cells or hemoglobin. Beta thalassemia occurs as a result of genetic changes to beta. The nhs sickle cell and thalassaemia screening programme also has detailed leaflets about being a beta thalassaemia carrier pdf, 804kb or a delta beta thalassaemia carrier pdf, 779kb. The type of thalassemia that a person has depends on how many and what type of traits for thalassemia a person has inherited, or received from their parents. Because they have one functioning copy of the gene, their health is not affected by beta thalassaemia. Difference between alpha thalassemia and beta thalassemia. Thousands of infants with hb bart syndrome and hbh disease are born each year, particularly in southeast asia. When the words trait, minor, intermedia, or major are used, these words describe how severe the thalassemia is. While the excess beta globin chains are capable of forming soluble homotetramers beta.
The beta globin gene hbb gene is located on the short arm of. Learn more about the impact of transfusiondependent beta thalassemia tdt. Each of these forms of thalassemia has different subtypes. For example, a person with beta thalassaemia minor has one changed copy of the hbb gene, and one unchanged copy of the gene. Thalassemia major is characterized by a hypochromic anemia due to a defect in the. My baby has hemoglobin dbeta thalassemia what does this mean. Aug 23, 2018 beta thalassemia is one of a group of hereditary blood conditions that result from reduced or absent synthesis of the beta globin chain of the hemoglobin molecule. In alpha thalassemia, there is a decrease in the number of alpha globin chains whereas in beta thalassemia it is the number of beta globin chains that goes down. Beta thalassemia can combine with other altered beta genes and cause problems also. The symptoms of thalassemia major generally appear before a childs second birthday.
Thalassemia omim 141800 is the most common inherited disorder of hemoglobin hb synthesis in the world, with gene frequencies varying between 1% and 98% throughout the tropics and subtropics. Beta thalassemia is a fairly common blood disorder worldwide. Started in 1995, this collection now contains 6767 interlinked topic pages divided into a tree of 31 specialty books and 732 chapters. This is the key difference between alpha and beta thalassemia. Diagnosis is typically by blood tests including a complete blood count, special hemoglobin tests, and genetic tests.
Learn more about causes, risk factors, screening and prevention, signs and symptoms, complications, diagnoses, treatments, and how to participate in clinical trials. Betathalassemia genetic and rare diseases information. Beta thalassemia trait and beta thalassemia disease. Beta thalassemia trait when you have one working copy of the beta globin gene and one nonworking copy you have beta thalassemia trait. The parents of a person with an autosomal recessive condition each carry one copy of the mutated gene and are referred to as carriers. The condition is caused by an abnormality in the production of the beta globin chain. Anyone can be a carrier of thalassaemia, but its much more common in people from certain ethnic backgrounds. For example, if one parent has beta thalassemia trait and the other parent has sickle cell trait another type of altered beta globin gene, there is a 25% chance of having a child with sickle beta thalassemia disease. It is passed down from one or both parents through their genes. Thalassemia major is the most severe form of beta thalassemia.
Thalassemia thalassemia is an inherited blood disorder in which the body produces an abnormal form of hemoglobin which results in excessive destruction of red blood cells and further leads to anemia. 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. Adult hemoglobin composed two alpha and two beta chains. Dec 21, 2014 the longterm outlook prognosis for people with sickle beta thalassemia varies depending on the severity of the condition. Arabic, cambodian, chinese, farsi, lao, tagalog, thai, and vietnamese. Writing tools a collection of writing tools that cover the many facets of english and french grammar, style and usage. There are two main types, alpha thalassemia and beta thalassemia. Beta thalassemia major is caused by a homozygous mutation betazero thalassemia of the betaglobin gene, resulting in the total absence of. The alpha chain is involved in alpha thalassemia and the beta chain is affected in the more familiar beta thalassemia. Laboratory diagnosis of hemoglobinopathies and thalassemia.
The abnormal hemoglobin can lead to anemia not enough rbcs in the body and other medical problems. Beta thalassaemia intermedia beta thalassaemia intermedia patients are more likely to need transfusion support. The minor variant features only a low risk of hemolysis. Beta thalassemia is a comparatively rare blood disorder in the united states, but alpha thalassemia is one of the most common autosomal recessive disorders in the world. The condition is called alpha thalassemia or beta thalassemia, depending on the specific genes that are missing or changed thalassemia. I cant find any information on being positive for beta thalassemia and only being a carrier of alpha thalassemia. Arabic, cambodian, chinese, farsi, lao, tagalog, thai. These hereditary mutations lead to anemia due to low hemoglobin levels and. It is probably the most common monogenic gene disorder in the world and is especially frequent in mediterranean countries. In its most severe form, this may cause beta thalassemia major or cooleys anemia, a blood disorder in which the lack of beta.
My baby has hemoglobin dbeta thalassemia your babys newborn screening test showed that he or she has hemoglobin dbeta thalassemia. Thalassemia is not just one disease but rather a complex series of genetic inherited disorders all of which involve underproduction of hemoglobin. Alpha thalassemia depresses only the production of the alpha chains, and beta thalassemia depresses only the production of the beta chains. This means it is passed down through the parents genes. Beta thalassemia is the most familiar type of thalassemia. Treatment of thalassemia major includes regular rbc transfusions, iron chelation and management of secondary complications of iron overload. In beta thalassemia, the beta globin genes are affected.
Heterozygotes with defects in two of the four genes result in alpha thalassemia. Heterozygotes for a single gene defect results in silent alpha thalassemia state. Combined longterm treatment of hemosiderosis with desferioxamine and dtpa in homozygous betathalassemia. Beta thalassemia can be further divided into a heterozygous minor and a homozygous major variant. Three clinical and hematological conditions of increasing.
Hemoglobin dbeta thalassemia will not change into a disease later on. Established in 1991, with more than 200 patients on active followup and over 800 patient visits every year, the center is one of the largest thalassemia. Beta thalassemia can be usually diagnosed using hemoglobin electrophoresis. Increased permeability of erythrocyte membrane in thalassemia. Oct 05, 2017 a defect in beta globin chains synthesis leads to beta thalassemia. Beta thalassemia mechanism of disease beta thalassemia is a rare, inherited blood disorder characterized by low levels of hemoglobin, which resides in red blood cells and carries oxygen throughout the body. Please use one of the following formats to cite this article in your essay, paper or report. Homozygous beta thalassemia is a severe, transfusion dependent anaemia that also causes infertility. Alpha and beta thalassemia are both conditions caused by genetic mutations. Beta thalassemia is an inherited blood disorder in which the body doesnt make hemoglobin normally. Beta thalassemia major symptoms include pale skin, irritability, growth retardation, swelling of the abdomen, and jaundice. In beta thalassemia, the gene for making beta globin chains doesnt work normally.
Constantoulakis m, economidou j, karagiorga m, katsantoni a, gyftaki e. Nov 27, 2019 beta thalassemia syndromes are a group of hereditary disorders characterized by a genetic deficiency in the synthesis of beta globin chains. Sickle beta zero thalassemia no normal hemoglobin is usually associated with a worse prognosis and more severe disease course than sickle beta plus thalassmia a reduced amount of normal hemoglobin. But the homozygous state with both genes for alpha thalassemia is lethal before birth because no alpha. A child can only be born with thalassaemia if they inherit these faulty genes from both parents.
In the case of one gene defect, betathalassemia minor trait. Depending on the type of beta thalassemia, symptoms. Two of these chains are identical and are designated the alpha chains. Alpha thalassemia usually caused by gene deletion beta thalassemia usually caused by mutation. Clinically, both alpha and beta thalassemia may occur in the. Thalassemia knowledge for medical students and physicians. In beta thalassemia, the heterozygous state called thalassemia minor is accompanied by no symptoms or at most by very mild anemia. Beta thalassemia is inherited as an autosomal recessive disease. Alphathalassaemia is inherited as an autosomal recessive disorder characterised by a microcytic hypochromic anaemia, and a clinical phenotype varying from almost asymptomatic to a lethal haemolytic anaemia. Feb 26, 2019 beta thalassemia is an inherited disorder of the blood that affects the hemoglobin inside red blood cells. Alpha thalassemia is a result of decreased production of alpha globins.
Pdf on mar 21, 2012, vefik arica and others published alpha thalassemia. In the homozygous state, beta thalassemia ie, thalassemia major causes severe, transfusiondependent anemia. Different people will have different symptoms, based on which type of beta thalassemia is inherited. Alpha thalassemia is a blood disorder in which the body has a problem producing alpha. Thalassemia intermedia is less clinically severe than betathalassemia major. Jan 19, 2017 know what are the signs and symptoms of thalassemia in adults. Beta thalassemia is an inherited hemoglobinopathy in which the production of one or both beta globin chains is impaired. Alpha thalassemia alpha thalassemia is due to impaired or absent production of alpha globin chains, which leads to a relative excess of gamma globin chains in the fetus and newborn, and excess beta globin chains in children and adults. Thousands of infants with beta thalassemia are born each year. Aug 05, 2015 beta thalassemia is one type of thalassemia, a blood disorder caused by dna mutations in cells that create hemoglobin.
Thalassemias national heart, lung, and blood institute nhlbi. Northern californias comprehensive thalassemia center at childrens hospital oakland, delivers quality care to thalassemia patients. It is probably the most common monogenic gene disorder. Thalassaemia is caused by faulty genes that affect the production of haemoglobin. A person who has thalassemia trait may not have any symptoms at all or may have only mild anemia, while a person with thalassemia. Beta thalassemia is caused by the reduced beta or absent beta 0 synthesis of the beta globin chains of the hemoglobin hb tetramer, which is made up of two alpha globin and two. If mutations allows production of a small amount of functional. Beta thalassemia occurs most frequently in people from mediterranean countries, north africa, the middle east, india, central asia, and southeast asia. I expected to be a carrier for beta thalassemia, not alpha thalassemia.
Hemoglobin is the part of red blood cells rbcs that carries oxygen throughout the body. Thalassemia is due to a deficit or absent production of. Beta thalassemia intermedia cooleys anemia foundation. Thalassemia is hereditary haemolytic disorders characterized by genes. Alpha thalassemia major with hemoglobin barts usually results in fatal hydrops fetalis. Thalassemias are inherited blood disorders, causing the body to make fewer healthy red blood cells and less hemoglobin than normal. Silent carriers of alpha thalassemia and persons with alpha or beta thalassemia trait are asymp tomatic and require no treatment. This course defines and discusses the disorder beta thalassemia and its genetic mutations that not only differentiate it from alpha thalassemia, but dictate the severity of the disease. Leads to severe anemia and may cause enlarged liver and spleen, resulting. There are two major forms of thalassemia as alpha thalassemia and beta thalassemia. The severity of alpha and beta thalassemia depends on how many of the four genes for alpha globin or two genes for beta globin are missing. Beta thalassemia is an inherited disease characterized by mild to severe anemia, poor growth, enlargement of the spleen, and skeletal changes. Combination of a triple alpha globin gene with beta thalassemia in a gypsy family. Affected fetuses have severe anemia and usually are stillborn.
Mcv and mch are low, but these patients are not transfusiondependent. Its causes, risk factors, complications and what are the treatment options for thalassemia. Betathalassemia prevalence, pathophysiology and inheritance. Anemia is a low red blood cell or low hemoglobin level. The decision to transfuse is an individualised one and requires an understanding of the alpha and beta genotype, red cell alloantibodies and red cell phenotype as well as careful discussion about risks and benefits.
But the homozygous state with both genes for alpha thalassemia is lethal before birth because no alpha chains can be made and without alpha chains there can be no hb f or. Translations of brochures about thalassemia, thalassemia trait, and hemoglobin h disease are available here in pdf format for the following languages. Alpha thalassemia, the heterozygous state with a single gene for alpha thalassemia, causes no symptoms or merely mild anemia because there is another gene still able to make alpha chains. Thalassemia is a treatable disorder that can be wellmanaged with blood transfusions and chelation therapy. Beta thalassemia major causes hemolytic anemia, poor. Four missing or mutated genes is a condition known as alpha thalassemia major or hydrops fetalis. The homozygous form of beta thalassemia thalassemia major is not immediately lethal because there is some production of hb f, which does not contain beta chains. For example, if both parents have the faulty gene that causes beta thalassaemia major, theres a 1 in 4 chance of each child they have being born with the condition. Signs and symptoms of thalassemia in adults care whizz. If beta thalassemia is poorly treated, it can lead to potentially lifethreatening complications. For instance, if a person receives a beta thalassemia trait from his father and another from his mother, he will have beta thalassemia major. Combination of a triple alphaglobin gene with beta. Beta thalassemia in children what is beta thalassemia in children. The exact form you have will affect the severity of your symptoms and your outlook.
Two of these chains are identical and are designated the alpha. Thalassemia thaluhseemeuh is a problem with red blood cells that is passed down from parents to children genetic. The two main types are called alpha and beta thalassemia, depending on which part of globin chain is produced in reduced amounts victor et al. Campbell, md louisiana state university health sciences center, new orleans, louisiana t he thalassemias named from the. Babies who have hemoglobin dbeta thalassemia are no more likely to get sick than any other baby. Silent carrier state the mildest form of beta thalassemia. For example, if one parent has beta thalassemia trait and the other parent has sickle cell trait another type of altered beta globin gene, there is a 25% chance of having a child with sickle beta thalassemia. Results in microcytic, hypochromic anemias of varying severity.
Thalassaemia minor can refer to people with either alpha or beta thalassaemia. Thalassaemia intermedia, guidelines on diagnosis and. This condition may be called alphathalassemia trait. Alpha thalassemia is a fairly common blood disorder worldwide. Normal alpha globin genes found on chromosome 16 people who do not produce enough alpha globin protein chains have alpha thalassemia. Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect on the anemia.