Sickle Cell Disease
Sickle cell disease (SCD) is a genetic disorder of red blood cells (RBCs). Normally, RBCs are disc-shaped, which allows them to flex and pass through even the smallest blood vessels. However, in this disease, the RBCs take on an abnormal crescent or sickle shape. This causes them to become sticky and rigid, making them more likely to get trapped in small vessels and block blood flow to various parts of the body. This can lead to pain and tissue damage. SCD is an autosomal recessive condition that requires two copies of the gene to have the disease. If only one copy of the gene is present, it is considered to be a sickle cell trait.
Types of Sickle Cell Disease
There are different types of sickle cell disease. The various types depend on the genes a person inherits from their parents.
Hemoglobin SS (HbSS):
It is a severe form that affects 65% of people with SCD. Individuals with this form inherit one gene for hemoglobin S from each parent. Most of their hemoglobin is abnormal, leading to chronic anemia.
Hemoglobin SC (HbSC):
It is a mild to moderate form that affects about 25% of people with the disease. Individuals with this type inherit a hemoglobin S gene from one parent and another abnormal type of hemoglobin C from the other parent.
Hemoglobin (HbS) Beta Thalassemia:
In this form, an individual has inherited a hemoglobin S gene from one parent and an abnormal type called beta thalassemia from their other parent.
Who is at Risk?
People from endemic malaria regions are more likely to be carriers. This covers individuals from:
- Africa
- India
- The Mediterranean
- Saudi Arabia
Symptoms of Sickle Cell Disease
Symptoms of sickle cell anemia usually appear around 6 months of age. They vary from person to person and may change over time. This includes:
- Anemia: Normal red blood cells typically live for about 120 days before they get replaced. But sickle cells usually die in 10 to 20 days, resulting in a shortage of red blood cells. This is known as anemia, which can cause fatigue.
- Episodes of pain: Periodic episodes of extreme pain, called pain crises, are a major symptom of sickle cell anemia.
- Swelling of hands and feet: Sickle-shaped red blood cells stop the blood circulation in the hands and feet, causing swelling in them.
- Frequent infections: Sickle cells can damage the spleen, raising the risk of developing infections.
- Delayed growth or puberty: A shortage of healthy red blood cells can slow growth in babies and children and delay puberty in teenagers.
- Vision problems: Small blood vessels that supply blood to the eyes can become blocked with sickle cells. This can damage the eye portion that processes visual images, called the retina, and lead to vision problems.