Over 200 diseasecausing hbb gene mutations have been identified, most of which are point mutations. Screening of five common beta thalassemia mutations in the. Reverse dotblot diagnosis of the less common betathalassemia mutations precludes the need for alternative, more technically challenging methods. Thalassemias are a diverse group of inherited disorders caused by genetic mutations affecting the globin chain component of the. Scribd is the worlds largest social reading and publishing site. The hbb gene provides instructions for making a protein called beta globin. Beta thalassemia is a hereditary disease affecting hemoglobin. This disorder is caused by mutations in the beta chain of the. The role of hfe mutations on iron metabolism in betathalassemia carriers. In betathalassemia, the mutations prevent red blood cells from producing enough of the oxygencarrying hemoglobin molecule, leading to. Thalassemia genetic and rare diseases information center. Standardofcare clinical practice guidelines 2012 standard of care guidelines 2012. Betathalassemia prevalence, pathophysiology and inheritance.
To determine the frequencies of beta thalassemia mutations in different states of india and to compare this with the available data in asian indians for a comprehensive catalogue of molecular. Genetic basis of beta thalassemia encoding genes on chromosome 11 short arm each cell contains 2 copies of beta globin gene beta globin protein level alpha globin protein level. Reverse dotblot detection of the africanamerican beta. Betathalassemia results from reduced synthesis of the hemoglobin beta chain. For language access assistance, contact the ncats public. India, with higher incidence in certain communities. As well as alpha and beta chains present in hemoglobin, about 3% of adult hemoglobin is made of alpha and delta chains. It is estimated that over 300,000 affected children are born each year, most with sickle cell disease, while about 60,00070,000 are born with.
This leads to a reduction in the number and ability of the red blood cells to. The betaglobin gene hbb gene is located on the short arm of. The beta globin gene hbb gene is located on the short arm of chromosome 11. Beta thalassemia major homozygous disorder resulting in severe transfusiondependent hemolytic anemia. Beta thalassemia disease two nonworking beta globin genes. Betathalassemia is a blood disorder that reduces the bodys production of hemoglobin.
This condition is caused by mutations in the hbb gene. Beta thalassemia intermedia severity lies between the minor and major. Betathalassemias are also very heterogeneous at the molecular level, with more than 200 diseasecausing mutations so far identified. Beta thalassemia major and beta thalassemia intermedia are usually inherited in an autosomal recessive manner, which means both copies of the hbb gene in each cell have mutations. Our findings showed that the distribution of beta thalassemia mutations differs from other previous data reported from khuzestan. Blood samples of patients with beta thalassemia major n 400 were collected from hospital transfusion centres and diagnostic laboratories in.
Currently, severe thalassemia is treated by blood transfusions, and a minority of patients are cured by bone marrow transplantation. Hb c betathalassemia is a blood disorder characterized by abnormal hemoglobin. Beta thalassemia is caused by changes mutations in the hbb gene while alpha thalassemia is caused by mutations in the hba1 andor hba2 genes. Hemoglobin consists of four protein subunits, typically two subunits of beta globin and two subunits of another protein called alphaglobin. The role of hfe mutations on iron metabolism in beta. This study aimed to characterize the spectrum of betaglobin gene mutations in pediatric patients who were followedup in. A study of the molecular lesions of betathalassemia in lebanon revealed the presence of eight different mutations in 25 patients with cooleys anemia. Pdf betathalassemia is one of the most common genetic disorders in thailand. The parents of a person with an autosomal recessive condition each carry one copy of the mutated gene and are referred to as carriers. Nonsense mutations and frameshift mutations tend to not produce any. Betathalassemia is caused by mutations in the hbb gene and is typically inherited in an autosomal recessive manner. Normal hemoglobin has two alpha and two beta peptide chains.
The hbb gene provides instructions for making a protein called betaglobin. The molecular basis of betathalassemia intermedia in. Beta thalassemia can combine with other altered beta genes and cause problems also. The name is derived from the greek word thalassa meaning the sea because the condition was first described in populations. The second patients cells contained a significant amount of a 20 nucleotide rna species, not initially evident in normal cells, from which part but not all of the large intervening sequence had been.
Inherited haemoglobin disorders, including thalassaemia and sicklecell disease, are the most common monogenic diseases worldwide. Beta thalassemia is an inherited hemoglobinopathy in which the production of one or both beta globin chains is impaired. This pdf is available for free download from a site hosted by. Beta thalassemia trait and beta thalassemia disease. Beta thalassemia is also known as mediterranean anemia. Most beta thalassemia cases are caused by a mutation in the hemoglobin subunit beta hbb gene, which provides instructions for making beta globin. The ivs1 position 110 mutation predominated with a.
Thalassemia mutations among thalassemia major patients. Pdf molecular analysis of betaglobin gene mutations among thai. In lebanon, betathalassemia is the predominant genetic defect. When there is a mutations in the hbb gene, it prevents the production of any betaglobin.
The beta globin gene is partially responsible for creating. The interaction of hbe and betathalassemia results in thalassemia phenotypes ranging from a condition indistinguishable from thalassemia major. Thalassemia is a blood disorder that is caused by dna mutations in cells that are responsible for producing haemoglobin. Betathalassemias are a group of hereditary blood disorders characterized by anomalies in. To determine the frequencies of betathalassemia mutations in different states of india and to compare this with the available data in asian indians for a comprehensive catalogue of molecular. Beta thalassemia is inherited as an autosomal recessive disease. Betathalassemia is inherited as an autosomal recessive disease. Gene spectrum analysis of thalassemia for people residing in. Beta thalassemia trait when you have one working copy of the beta globin. Thalassemia is an inherited disease of faulty synthesis of hemoglobin.
If you have beta thalassemia trait, it is possible to pass it to your children. The absence of betaglobin is referred to as beta zero b0 thalassemia. If you have problems viewing pdf files, download the latest version of adobe reader. Beta thalassemia is a companion course to alpha thalassemia. Thalassemia is due to a deficit or absent production of. This course defines and discusses the disorder beta thalassemia and its genetic mutations that not only differentiate it from alpha. Just as with beta thalassemia, mutations that affect the ability of this gene to. Different people will have different symptoms, based on which type. A variety of thalassemia phenotypes can result from simultaneous inheritance of two different thalassemia mutations from each parent or coinheritance of thalassemia together with structural. Researchers develop new strategy to treat sickle cell.
Although most of the molecular lesions involve the structural. Beta thalassemia trait and beta thalassemia disease beta thalassemia disease is an inherited blood. Mouse models are proving to be useful in assessing the potential of gene therapy. In beta thalassemia, the gene for making beta globin chains doesnt work normally. Each of these disorders are caused by a mutation of the beta globin gene. The clinical manifestations include hemolytic anemia and. This article outlines the molecular mechanisms underlying the quantitative reduction in. For example, if one parent has beta thalassemia trait and the other parent has sickle cell trait another type of altered. As with about half of all hereditary diseases, an inherited mutation damages the assembly of the messengertype rna mrna that is. Betathalassemia genetic and rare diseases information. Hematologic features of betaglobin gene mutation type. Betathalassemia associated with other hb anomalies. Thalassemia mutations among thalassemia major patients in basrah province iraq abstract.
400 39 888 604 699 145 1321 1356 1451 57 897 517 1541 1147 339 527 1644 969 664 786 1384 1107 637 1075 574 1146 511 411 1106 192 415 1060 144 337 326 440 418 230 158 136 132 902 160 858 1454 1450 1420 19 1422 944