In sickle cell anaemia defect is in which chain -

Sickle cell disease is a common hereditary hemoglobinopathy caused by a point mutation in beta globin that promotes the polymerisation of deoxygenated Hb, leading to red cell distoion, hemolytic anaemia, micro vascular obstruction and ischemic tissue damage. In the 6th codon of Beta globin a point mutation which leads to replacement of a glutamate residue with a valine residue occurs Ref ; Robbins and Cotran Pathologic basis of disease.South Asia Edition volume 1.page no. 635