Sickle cell disease is due to

(Point mutation) (628-R) (227-426-Basicpathology> 8th)Sickle cell disease is an important hereditary hemoglobinopathy, a type of disease characterized by production of defective hemoglobins.Sickle cell disease is caused by a point mutation at the sixth position of the b-globin chain leading to the substitution of a valine residue for a glutamic acid residue.Sickle syndromes occurs in 3 different forms (394-HM 5th)1. As heterozygous state for HbS: Sickle cell trait (AS)2. As homozygous state for HbS: Sickle cell anaemia (SS)3. As double heterozygous states eg. Sickle p-thalassaemia Sickle-C-disease, sickle-D disease (SD)Frame-shift mutation - occurs when there is insertion or deletion of one or two base pairs in the DNA sequence eg. Cystic fibrosis