Beta thalassemias are a group of inherited blood disorders. They are forms of thalassemia .. to remove the excess iron. Transmission is autosomal recessive; however, dominant mutations and compound heterozygotes have been reported. Thalassemias are inherited blood disorders characterized by abnormal hemoglobin production. 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 syndromes are a group of hereditary disorders characterized by a genetic deficiency in the synthesis of beta-globin chains. In the homozygous .
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Thalassemias are inherited blood disorders characterized by abnormal hemoglobin production. Thalassemias are genetic disorders inherited from a person’s parents.
OMIM Entry – # – BETA-THALASSEMIA
Treatment depends on the type and severity. As ofthalassemia occurs in about million people, with about heterozygkte, having severe disease. For the autosomal recessive forms of the disease, both parents must be carriers for a child to be affected.
Having a single genetic variant for thalassemia may protect against malaria and thus can be an advantage. Heteroyzgote thalassemias are classified according to which chain of the hemoglobin molecule is affected.
Two gene loci and so four alleles exist. It is also connected to the deletion of the 16p chromosome. Beta thalassemias are due to mutations in the HBB gene on chromosome 11,  also inherited in an autosomal, recessive fashion. The severity of the disease depends on the nature of the mutation and on the presence ghalassemie mutations in one or both alleles.
The situation of both alleles determines the clinical picture:. Just as with beta beha, mutations that affect the ability of this gene to produce delta chains can occur. Thalassemia can coexist with other hemoglobinopathies. The most common of these are:. Thalassemia can be diagnosed via a complete blood counthemoglobin electrophoresis, and DNA testing.
The American College of Betq and Gynecologists recommends all people thinking of becoming pregnant be tested to see if they have thalassemia. A screening policy exists in Cyprus to reduce the rate of thalassemia, which, since the program’s implementation in the s which also includes prenatal screening and abortionhas reduced the number of children born with the disease from one of every births to almost zero. When both are microcytic, their hemoglobin A2 concentrations are measured.
If both have a concentration above 3. Large scale awareness campaigns are being organized in India  both by government and non-government organizations in favor of voluntary premarital screening to detect carriers of thalassemia and marriage between both carriers are strongly discouraged. They should avoid routine use of iron supplements ; iron deficiency can develop, though, during pregnancy or from chronic bleeding.
People with severe thalassemia require medical treatment. A blood transfusion regimen was the first measure effective in prolonging life.
Multiple blood transfusions can result in iron overload. The iron overload related to thalassemia may be treated by chelation therapy with the medications deferoxaminedeferiproneor deferasirox. Deferoxamine is only effective via daily injections which makes its long-term use more difficult. It has the benefit of being inexpensive and decent long-term safety. Adverse effects are heterozygot skin thalaassemie around the thalasdemie site and hearing loss. Deferasirox has the benefit of being an oral medication.
Common side effects include: It however is not effective in everyone and is probably not suitable in those with significant cardiac heterozygite related to iron overload.
The cost is also significant. Deferiprone is a medication that is given by mouth. Nausea, vomiting, and diarrhea are relatively common with its use. There is no evidence from randomized controlled trial to support zinc supplementation in thalassemia.
Bone marrow transplantation may offer the possibility of a cure in young thalassemis who have heterozybote HLA -matched donor. If the person does not have an HLA-matched compatible donor, another method called bone marrow transplantation BMT from haploidentical mother to child mismatched donor may be used. The best results are with very young people.
The beta form of thalassemia is particularly prevalent among Mediterranean peoples, and this geographical association is responsible for its original name. In Europe, thslassemie highest concentrations of the disease are found in Greececoastal regions in Turkey particularly the Aegean Region such as IzmirBalikesirAydinMuglaand Mediterranean Region such as AntalyaAdanaMersinin parts of Italyparticularly southern Italy and the heterozygotw Po valley.
The major Mediterranean islands except the Balearics such as SicilySardiniaMaltaCorsicaCyprusand Crete are heavily affected in particular.
Other Mediterranean people, as well as those in the vicinity of the Mediterranean, also have high rates of thalassemia, including people from West Asia and North Africa. Nowadays, it is found in heterizygote living in Africa, the Americas, and in Tharu people in the Terai region of Nepal and India. Thalassemias are particularly associated with people of Mediterranean origin, Arabs especially Palestinians and people of Palestinian descent thlassemie, and Asians.
Thalassemias also occur in descendants of people from Mediterranean countries e.
Greece, Italy, Spainand othersin Latin America. Estimates suggest that approximately ghalassemie. In general, poorer populations only have access to limited diagnostic facilities together with blood transfusions. In some developing countries, there are virtually no facilities for diagnosis or management of thalassemia. It was coined because the condition called “Mediterranean anemia” was first described in people of Mediterranean ethnicities.
The word thalassemia was first used in Inin Spain, a baby was selectively implanted to be a cure for his brother’s thalassemia. The child was born from an embryo screened to be free of the disease before implantation heterozygoye in vitro fertilization. The baby’s supply of immunologically compatible cord blood was saved for transplantation to his brother.
The transplantation was considered successful. Gene therapy is being studied for thalassemia. The HSCs then have a beta-globin gene added using a lentiviral vector. After destroying the affected person’s bone marrow with a dose of chemotherapy a myeloablative conditioning regimenthe altered HSCs are infused back into the affected person where they become engrafted in the bone marrow where they proliferate.
This potentially results in a progressive increase in hemoglobin A2 synthesis in all subsequent developing red blood cells, with resultant resolution of the anemia. While one person with beta thalassemia has no longer required blood transfusions following treatment within a research thalasaemie, it is not an approved treatment as of HbF induction is an attempt to reactivatefetal globin gene transcription.
From Wikipedia, the free encyclopedia.
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Beta Thalassemia –
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