Presentation on theme: "Thalassemia & Treatment"— Presentation transcript:
1 Thalassemia & Treatment PHM 226, ExampleInstructor: Dr. Jeffrey HendersonThalassemia & TreatmentGenetic disruption of the synthesis of hemoglobinVictor WongTracy WongBao NguyenPHM 226 January 13th, 2003Reference:&
2 What is thalassemia?Genetic blood disorder resulting in a mutation or deletion of the genes that control globin production.Normal hemoglobin is composed of 2 alpha and 2 beta globinsMutations in a given globin gene can cause a decrease in production of that globin, resulting in deficiencyaggregates become oxidized damage the cell membrane, leading either to hemolysis, ineffective erythropoiesis, or both.2 types of thalassemia: alpha and beta.
3 DemographicsThe thalassemia gene may be maintained in the human population, in part because of the greater immunity of heterozygous individuals against malaria and is found in parts of the world where malaria is commonThese include Southeast Asia, China, India, Africa, and parts of the Mediterranean.
4 Alpha Thalassemiamutation of 1 or more of the 4 alpha globin genes on chromosome 16severity of disease depends on number of genes affectedresults in an excess of beta globins
5 Silent Carriers (heterozygotes +/-) 3 functional alpha globin genesNo symptoms, but thalassemia could potentially appear in offspring
6 Alpha Thalassemia Trait 2 functional globin genesresults in smaller blood cells that are lighter in colourno serious symptoms, except slight anemia
7 Hemoglobin H Disease 1 functional globin gene results in very lightly coloured red blood cells and possible severe anemiahemoglobin H is susceptible to oxidation, therefore oxidant drugs and foods are avoidedtreated with folate to aid blood cell production
8 Alpha Thalassemia Major no functional globin genesdeath before birth (embryonic lethality)
9 Beta Thalassemia mutations on chromosome 11 hundreds of mutations possible in the beta globin gene, therefore beta thalassemia is more diverseresults in excess of alpha globins
10 Beta Thalassemia Trait slight lack of beta globinsmaller red blood cells that are lighter in colour due to lack of hemoglobinno major symptoms except slight anemia
11 Beta Thalassemia Intermedia lack of beta globin is more significantbony deformities due to bone marrow trying to make more blood cells to replace defective onescauses late development, exercise intolerance, and high levels of iron in blood due to reabsorption in the GI tractif unable to maintain hemoglobin levels between 6 gm/dl – 7 gm/dl, transfusion or splenectomy is recommended
12 Beta Thalassemia Major complete absence of beta globinenlarged spleen, lightly coloured blood cellssevere anemiachronic transfusions required, in conjunction with chelation therapy to reduce iron (desferoxamine)
13 More Permanent Options Bone Marrow TransplantsReplacing patient’s marrow with donor marrowFirst performed on thalassemia patient in 1981Difficult, because donor must be exact match for recipientEven a sibling would only have a 1 in 4 chance of being a donorCord Blood TransplantsRich in stem cellsAlso needs to be an exact match