The mutation that causes SCD causes what kind of change in the structure of hemoglobin?

A group of blood disorders generally passed on from the parents to the offspring is known as SCD or sickle cell disease. Of the disease, the most common is the SCA or sickle cell anemia. In the disease, the red blood cells comprise an abnormal form of the oxygen-carrying protein hemoglobin.  

Generally, humans comprise hemoglobin A, A2, and F types. Of the three types, the hemoglobin F dominates till the age of 6 weeks, after which hemoglobin A dominates till the end of life. However, in the persons diagnosed with SCA, at least one of the beta-globin subunits in hemoglobin A gets substituted by a different form known as hemoglobin S. In the disease, a single nucleotide mutation in the beta-globin gene takes place, in this at 6th position, the glutamic acid gets replaced by Valine.  

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