what is A change in just one DNA base for the gene that codes for the protein causes sickle shaped red blood cells?

A change in just one DNA base in the gene that codes for the protein hemoglobin can lead to sickle cell disease. This specific mutation substitutes adenine for thymine in the gene, resulting in the production of abnormal hemoglobin called hemoglobin S. The altered hemoglobin causes red blood cells to assume a rigid, sickle shape, leading to various complications, including reduced oxygen transport and increased risk of blockages in blood vessels. This single base change exemplifies how small genetic variations can have significant effects on health.