Sickle Cell Anemia Study

Blood disorders can affect one of the four components of blood: erythrocytes (red blood cells), leukocytes (white blood cells), platelets, or plasma. The blood is affected by sickle cell diseases causing an abnormality or mutation in the hemoglobin of red blood cells. The most common type of genetic blood disorders is sickle cell diseases with sickle cell anemia being the most dangerous (Addis, 2010). Sickle cell anemia is characterized into the group of sickle cell diseases. The phenotype number for sickle cell anemia is #603903 on the HBB gene/ locus (OMIM, 2014). Sickle cell anemia can also be known as HbS disease, hemoglobin S disease, and hemoglobin SS disease (NHLBI, 2012). Sickle cell anemia is identified by both its description and …show more content…
Sickle cell anemia is inherited as a complete dominance, a form of Mendelian genetics. The disease is an autosomal recessive genetic disorder (Addis, 2010). The alleles HbA and HbS in hemoglobin control the genetic expression of the trait. Hemoglobin (Hb) is a protein made of iron that is a major component of a red blood cell also known as an erythrocyte. The HbA allele is dominant to the HbS allele. The disease is only inherited when the homozygous recessive or HbS/ HbS genotype is present. The homozygous dominant genes of HbA/ HbA do not pass on the trait while the heterozygous normal phenotype HbA/ HbS is a carrier of the sickle cell trait (Klug, 2012 pg. 359). For example, two parents who are both heterozygous have a 25% chance of having a child sick with sickle cell anemia creating a 3:1 ratio of not having sickle cell anemia to having sickle cell anemia. When the individual is homozygous recessive and has sickle cell anemia, the hemoglobin S (HbS) becomes abnormal and loses its shape into a sickle, crescent like cell shape (Angerio & Lee, 2003). The inheritance of sickle cell anemia is linked with other sicknesses and can affect the mode of inheritance for those