Sickle Cell. These are the sickle-shaped blood cells of someone with sickle cell anemia, a genetic disease common among those of African descent. Sickle cell anemia is the result of a point mutation, a change in just one nucleotide in the gene for hemoglobin.This mutation causes the hemoglobin in red blood cells to distort to a sickle shape when deoxygenated. The sickle-shaped blood cells clog in the capillaries, cutting off circulation.ome well-known inherited genetic disorders include cystic fibrosis, sickle cell anemia, Tay-Sachs disease, phenylketonuria and color-blindness, among many others. All of these disorders are caused by the mutation of a single gene.