What is sickle cell
nearer Sickle cell disorder is an inherited blood condition which arises as a result of the replacement of specific amino acids in the protein ‘globin’ sequence of haemoglobin in the red blood cell.
Typically, a person living with sickle cell disorder would have genotypes such as HbSS, HbSC, HbSE, HbSD, etc. However, the most commonly found in sub-Saharan Africa are HbSS and HbSC.
Usually, a person will inherit two copies of genes from each parent to form the ‘globin’ chain that exists in ‘haemoglobin’. The haemoglobin is the iron-protein complex present in the red blood cell.
This combination of the two genes is referred to as ‘haemoglobin genotype’ or simply ‘genotype’. Types of genotype include but are not limited to HbAA, HbAS, HbAC, HbSS, HbSC, and HbCC.
A person is said to have the sickle cell trait in their haemoglobin genotype if they inherit a combination of a single copy of the normal gene and then a copy of the sickle cell gene. Such an individual is called ‘sickle cell carrier’ and would typically have the genotype AS.
The individual, however, does not exhibit any symptoms of sickle cell disorder. But they can pass the sickle cell gene to offsprings. Sickle cell trait is not sickle cell disorder.
Beta-thalassemia is an inherited blood disorder which arises as a result of the deletion of specific amino acids in the protein ‘globin’ sequence of haemoglobin in the red blood cell.
It leads to a low level of haemoglobin in the red blood cell. It may be presented as symptoms of shortness of breath, jaundice, slow growth, among others.
Beta-thalassemia also plays a crucial role in the determination of genotype of humans, especially those in the Mediterranean, India, North Africa, the Middle East, and so on. It is represented by the sign ‘β.’