镰刀细胞贫血.ppt

学生：梁茂丽 09级临床七年2班 学号：2009021214 Sickle cell anemia Sickle cell anemia(or sickle cell disease,SCD) a disorder of the blood characterized by abnormal, sickle-shaped red blood cells caused by an inherited abnormal hemoglobin. Sickle cell anemia: autosomal recessive inheritance molecular cause of Sickle cell anemia Hemoglobin structure: tetramer Hb A ?2?2 2 ? chians ：?1 、 ?2 2 ? chains: ?1 、?2 Sickle cell anemia : HbA HbS molecular cause of Sickle cell anemia  One Point Mutation Causes the Disease Sickle hemoglobin tetramers (HbS) polymerize When deoxygenated Sickle RBCs occur Shorter life erythrocyte injury blocking the flow of blood ……. Symptoms : anemia、 pain crises… molecular cause of Sickle cell anemia Prenatal diagnosis How? Step 3. Amplify the fragment containing the variation by PCR Cut with an appropriate restriction enzyme Step 1. PCR-RFLP Polymerase chain reaction-restriction fragment length analysis techniques which are developed on the basis of the PCR technique. Step 2. Run products on gel electrophoresis Genotype analysis Taq DNA polymerase Deoxynucleoside triphosphates (dNTPs) PCR reaction system Polymerase Chain Reaction (PCR) : a molecular biological method for amplifying (creating multiple copies of) specific DNA fragments in vitro. DNA template Buffer solution Two primers Steps of PCR: Steps of PCR: annealing denaturation extension PCR-RFLP Restriction Fragment Length Polymorphism (RFLP): are variation in DNA fragment banding patterns of electrophoresed restriction digests of DNA from different individuals. Often due to the presence and absence of a restriction enzyme cleavage site at one place in the genome MstII restriction nuclease recognizes the sequence CCTNAGG where N = A, C, G or T PCR-RFLP Advantages Disadvantages Inexpensive Easy to design and perform 3.Widely used in many fields. ... 1.Some re