Defect in Snurps causes?: (A) Sickle cell anemia, (B) Thalassemia, (C) Marfan syndrome, (D) EDS
Answer is B. Defective splicing (defect in snurps) is the most common mutation causing thalassemia. Molecular defect in pathogensis of thalassemia:? A) b-Thalassemia Most common type of genetic abnormality in b-thalassemia is point mutation i.e., nonsense. Some may also occur due to deletion or inseion i.e., frame shift mutations. Defect may occur at different steps of b-chain synthesis: i) Splicing mutations Mutations leading to aberrant splicing are the most common cause of P-thalassemia. ii) Chain terminator mutations This cause premature termination of mRNA translation. iii) Promoter region mutations This results in transcription defect. B) a-Thalassemia The most common cause of reduced a-chain synthesis is deletion of a-globin genes. Rarely nonsense mutation may also cause a-thalassemia.