Sickle Cell Disease (SCD)
Table of Contents
Sickle cell disease (SCD) is a group of inherited red blood cell disorders. Red blood cells contain hemoglobin, a protein that carries oxygen. Healthy red blood cells are round, and they move through small blood vessels to carry oxygen to all parts of the body. With sickle cell disease the red blood cells die early.
Diagnosis
SCD is diagnosed with a simple blood test. SCD can be diagnosed while the baby is in the womb. It mostly found at birth during routine newborn screening tests at the hospital.
Causes of Sickle Cell Disease
SCD is a genetic condition that is present at birth. It is inherited when a child receives two genes (hemoglobin S gene): one from each parent.
Sickle Cell Trait
People who have sickle cell trait (SCT) inherit a hemoglobin S gene from one parent and a normal gene (one that codes for hemoglobin “A”) from the other parent. people who have SCT can pass the abnormal hemoglobin S gene on to their children. People who inherit one sickle cell gene and one normal gene have sickle cell trait (SCT). People with SCT usually do not have any of the symptoms of sickle cell disease (SCD), but they can pass the trait on to their children.
Types of Sickle Cell Disease
There are several types of SCD.
HbSS
This is commonly called sickle cell anemia and is usually the most severe form of the disease. People who have this form of SCD inherit two hemoglobin S genes (abnormal hemoglobin), one from each parent. This causes the red cells to become rigid, and sickle shaped.
HbSC
This is usually a milder form of SCD. People who have this form of SCD inherit a hemoglobin S gene from one parent and a hemoglobin C gene, a different type of abnormal hemoglobin from the other parent.
HbS beta thalassemia
People who have this form of SCD inherit a hemoglobin S gene from one parent and a hemoglobin beta thalassemia gene, another type of abnormal hemoglobin from the other parent. There are two types of beta thalassemia: “zero” (HbS beta0) and “plus” (HbS beta+). Those with HbS beta0-thalassemia usually have a severe form of SCD. People with HbS beta+-thalassemia tend to have a milder form of SCD.
HbSD, HbSE, and HbSO
These are rare types of SCD. People who have these forms of SCD inherit one hemoglobin S gene and one gene that codes for another abnormal type of hemoglobin (“D,” “E,” or “O”). The severity of these rarer types of SCD varies.