What is Sickle Cell Disease? Its Forms/Types

What is Sickle Cell Disease?

Sickle cell disease (SCD) is a genetic disease that infects people who inherit 2 genes that carry sickle hemoglobin (Hb SS gene), 1 from each of their parents. If the gene a person receives is only from a single parent, then instead of SCD, the person will have a condition called sickle cell trait (SCT) or ‘carrier’. Only people with 2 copies of the gene can have this disease. For this reason, a person with SCT has 1 HB SS gene and 1 normal hemoglobin gene.

SCD is a red blood cells (RBCs) disease. RBCs have the shape of discs. This makes them flexible enough to travel through blood vessels irrespective of how small they are. However, when it comes to SCD, RBCs have an abnormal crescent shape, like a sickle. This renders them sticky, rigid, and inflexible, making them susceptible to being trapped in small vessels. When trapped, they block the proper circulation of blood to different body parts, causing VOC (vaso-ocular crisis) and pain episodes. With time, the results can be pain and organ damage.

What Form of Sickle Cell Disease is the Most Severe Form?

Sickle cell anemia (Hb SS or SS disease) is regarded as the most severe and common form of sickle cell disease. The cases develop in children at the age of between 4 and 6 months. They inherit a copy of the hemoglobin S gene (Hb SS gene) from each of their parents.

The SS symptoms have similarities with other types of SCD, but affect people more severely and at a higher rate.

SS disease symptoms include fussiness, kidney-related bedwetting problems, swollen feet/or hands, yellow eyes or skin (jaundice), frequent infections, irritability, etc.

What are the Types of Sickle Cell Disease?

Sickle cell disease is a general name for a group of hemoglobin-related genetic diseases. Hemoglobin is made of 2 alpha chains & 2 beta-globin chains. It is a red blood cell protein that carries oxygen.

If beta-globin genes undergo mutation (or defect), the result can be sickle cell disease!

Major Types of Sickle Cell Disease

Hemoglobin SS Disease

Hemoglobin SS disease, also known as Sickle Cell Anemia (SS) is the most common and severe type of SCD. It is caused by inheriting 2 copies of the hemoglobin S gene from each parent. This means the body of the patient can only produce hemoglobin S. People with this form of SCD experience the most severe symptoms at a higher rate.

Sickle Hemoglobin-C Disease

Sickle Hemoglobin-C Disease (Hb SC) is the second most common and severe type of SCD. It infects an individual when one parent passes the Hb beta S gene to the child and another passes the Hb C gene to that very child. There are similarities between Hb SC and sickle cell anemia symptoms but Hb SC symptoms are usually less frequent and severe.

Sickle Beta-Plus Thalassemia

Beta-plus Thalassemia also known as SB+ is caused by inheriting 1 copy of the hemoglobin beta plus (SB+) thalassemia gene and a Hb beta S gene. 1 each from each parent! SB+ patients can produce normal hemoglobin to some extent. This leads to less severe symptoms. However, they still have the risk of developing health complications.

Sickle Beta-Zero Thalassemia

When a person inherits 2 copies of the Hb beta S gene, 1 from each parent, it causes Beta-Zero Thalassemia (SB 0) .This type of SCD shares some similarities with sickle cell anemia since with it, the body can only produce hemoglobin S.

Keep reading my blog to learn all you need to know about sickle cell disease and other health topics. You can also comment below or ask me a question for clarity if necessary.