haemoglobinopathies

haemoglobinopathies

1. بسم الله الرحمن الرحيم Hemoglobinopathies By\ Mohamed Osama Elmoghazy

2. Definition : The hemoglobinopathies are any of a group of diseases characterized by abnormalities, both quantitative and qualitative, in the synthesis of hemoglobin (Hb). Hemoglobinopathies

3. Hemoglobinopathies Qualitative Quantitative Sickle cell anemia Thalassemia

4. There is an alternation in the amino acid structure of the polypeptide chains of the globin fraction of hemoglobin. The best-known example is Hbs , found in sickle cell anaemia . Quantitative abnormalities

5. In quantitative abnormalities ( the thalassemia ), the amino acid sequence is normal but polypeptide chain production is impaired or absent for a variety of reasons. In these conditions the ratio of alpha to non-alpha chain production is distributed. Alpha-thalassemia . Beta-thalassemia . Quantitative abnormalities

6. Hemoglobin C Like HbS, HbC is a hemoglobin variant that has a single amino acid substitution in the sixth position of the β-globin chain . A lysine is substituted for the glutamate ( α2β2 6Glu-Lys ). This unstable hemoglobin precipitates in red blood cells (RBCs) to form crystals.

7. have a relatively mild, chronic hemolytic anemia. These patients do not suffer from rises , and specific therapy is required . behaves like a mild form of sickle cell disease. It is associated with a reduced frequency of crises but is not commonly associated with Complications in pregnancy and retinal vein thrombosis. Patients homozygous: Patients heterozygous :

8. Hemoglobin E  (HbE) is an abnormal  hemoglobin  with a single point  mutation  in the β chain. At position 26 there is a change in the amino acid, from  glutamic acid  to  lysine . It is very common in Southeast Asia   but has a low frequency amongst other races . Hemoglobin E

9. Homozygotes for HbE(EE): They have a mild hemolytic anemia and mild splenomegaly. They are asymptomatic, the hemoglobin level is normal but red cells are microcytic . This causes a mild anemia but the combination of heterozygous and β-thalassemia produces a variable anemia which can be as severe as β- thalassaemia major . Heterozygotes for Hb E:

10. references ( 1)- http ://www.cdc.gov/ncbddd/hemoglobinopathies/ (2)-Davidson's, chapter 6, page: (1012_1014),fifth edition. (3)- Kumar & Clark, chapter 8, page: 419 ,sixth edition. (4)- http://www.urmc.rochester.edu/medicine/genetics/ (5)- Lippincotts -Illustrated- Reviews,chapter 4, page 168, fifthth edition.

11. Thank you