Sickle cell disease (SCD) isn’t actually one disease, it is a group of inherited disorders of the red blood cells (RBCs). Normal, healthy RBCs have a disk shape, and they float in the blood to carry oxygen around the body. In doing this, they sometimes pass through small blood vessels which are small channels through which blood passes to reach its destination.
In someone with sickle cell disease, the RBCs become very hard and are shaped like a C-shaped farm tool called a “sickle”. Because these sickle cells are not healthy, they die earlier than normal RBCs, leading to constant shortage of RBCs in the body of the individual (anemia). Furthermore, as they pass through these small blood vessels, they get stuck and obstruct the normal flow of blood, causing pain, infection, and stroke.
Types of SCD
There are a number of SCD types. Highlighted below are the common types of sickle cell disease:
This is the most common and most severe type of SCD. People with this type of SCD inherit 2 sickle cell genes (SS), one from each of their parents. It is also called sickle cell anemia. Therefore, sickle cell anemia is only a subtype of sickle cell disease.
This is a milder form of SCD. People with this type of SCD inherit one sickle cell gene (S) from one parent and another abnormal hemoglobin gene (C) from the other parent. Hemoglobin is a protein in RBCs which they use to carry oxygen to different parts of the body.
HbS beta thalassemia
People who have this SCD type inherit one sickle cell gene (S) from one parent and one beta thalassemia gene (B-thal) from the other parent. Beta thalassemia is another type of anemia which results from a defect in the proteins that makes up hemoglobin. Thus, RBCs have a problem carrying oxygen to different parts of the body.
There are two types of beta thalassemia: beta 0 and beta +. Those who have Hbs beta 0 thalassemia have a more severe form of SCD than those with HbS beta + thalassemia.
There are a few other rare types of SCD which include HbSD, HBSE and HbSO
The unifying point about SCDs is that they all inherit two abnormal hemoglobin genes from both parents (Either 2 sickle cell genes or a sickle cell gene and another abnormal hemoglobin gene).
If an individual inherits a sickle cell gene from one parent and a normal hemoglobin gene from the other parent, the individual is said to have sickle cell trait (AS). These people do not have symptoms of sickle cell disease, but can pass the gene on to their children.
Cause of SCD
SCD is a genetic condition that an individual is born with. This, it is usually inherited when the child receives two sickle cell genes from each parent or one sickle cell gene from one parent and one abnormal hemoglobin gene from the other parent.
The symptoms of SCD usually start from 5 months of age and they vary among individuals. Some of the symptoms include:
- Fatigue and tiredness form anemia
- Pale skin
- Episodes of pain in the chest, abdomen, joints and bones.
- Swelling of the hands and feet
- Recurrent and frequent infections
- Delayed puberty
- Problems with vision
- Abdominal swelling
The complications arise from inadequate management and follow-up. Some of the complications include:
- Yellow discoloration of the eyes
- Ulcers in the legs
- Gallstones in the gall bladder
- Priapism (long-standing, painful erection)
- Pregnancy complications
SCD is usually diagnosed using a blood test. It mostly diagnosed after birth when the doctor routinely screens the newborns blood. Sometimes, SCD can be diagnosed before birth. Early diagnosis and prompt treatment are essential because children with SCD are at an increased risk of many health problems.
- Medications (e.g hydroxyurea) to reduce pain
- Immunizations to prevent infections
- Blood transfusion when the blood levels are very low
- The only known cure for SCD is a stem cell transplant, also known as bone marrow transplant. However, it is a very risky procedure. Because of the associated risks, it is recommended only for people, usually children, who have significantly distressing symptoms and/or complications of SCDs.