What is Sickle Cell Disease

Sickle Cell Disease is a group of inherited red blood cell disorders, caused by a single gene mutation, resulting in red blood cells that become hard and sticky and look like a “sickle”. The sickle cells die early, which causes a constant shortage of red blood cells, or anemia. The sickle cells get stuck in small blood vessels and impede blood flow, causing severe pain, chronic inflammation, and organ damage.

Nearly every organ in the body can be adversely affected by SCD, which ultimately results in multiple organ failure and premature death, occurring mostly in children under five years, adolescents and pregnant women.

Sickle cell disease occurs when an individual inherits two sickle hemoglobin genes from both parents or a combination of one sickle hemoglobin gene and another abnormal hemoglobin gene from the parents.

Sickle cell disease is the most common genetic disease in the world and is most common in people whose families come from Africa, South or Central America (especially Panama), Caribbean islands, Mediterranean countries (such as Turkey, Greece, and Italy), India, and Saudi Arabia.

There are several different types of sickle cell disease.  Sickle cell disease is the name for a group of disorders that all have predominantly sickle hemoglobin. The most common types of sickle cell disease found in Africa are:

  • Sickle Cell Anemia (Also known as Hb SS or Homozygous Sickle Cell Disease)
  • Sickle Hemoglobin C Disease (Also known as Hemoglobin Hb SC Disease)
  • Sickle Beta Thalassemia Disease (Sickle Beta Plus Thalassemia and Sickle Beta Zero Thalassemia Disease)

What is Sickle Cell Trait

Sickle cell trait is an inherited blood disorder that affects approximately 300 million people worldwide and can also be associated with significant morbidity and mortality.

Unlike sickle cell disease, individuals with sickle cell trait carry only one defective gene and typically live normal lives. Rarely, extreme conditions such as severe dehydration and high-intensity physical activity can lead to serious health issues, including sudden death, for individuals with sickle cell trait.

If an individual has sickle cell trait, it means that he or she carries or has inherited a single copy of the gene that causes sickle cell disease. It is not a disease. In general, people with sickle cell trait enjoy normal life spans with no medical problems related to sickle cell trait.

Although sickle cell trait can never become sickle cell disease, it is possible however for individuals with sickle cell trait to pass the gene to their children. 

Symptoms & Diagnosis

Normal healthy red blood cells are flexible and round, move easily through blood vessels and carry oxygen to all parts of your body. In sickle cell disease, red blood cells are not round. Instead they are curved like a crescent, or sickle. This is because the hemoglobin in the red blood cell is abnormal. The sickle-shaped red blood cells cannot move easily and can become stuck in small blood vessels, blocking them.

As a result, the blood supply to that part of the body is restricted. Organs that do not receive normal blood flow will become damaged over time. Restricted blood flow is what causes the complications of sickle cell disease, which can range from mild fatigue to more severe symptoms such as stroke, infections, and pain in the bones and chest requiring treatment in the hospital. The complications vary from person to person, with some having to see their doctor often and others less so.

There is no cure for most people with sickle cell disease, as they are born with the abnormal hemoglobin. However, there are treatments and medicines that control or prevent the health problems caused by the disease.

Symptoms of Sickle Cell Disease

The signs and symptoms of sickle cell disease vary. Some people have mild symptoms. Others have very severe symptoms and often are hospitalized frequently for treatment. Sickle cell disease is present at birth, but many infants don’t show any signs until after 4 months of age. The most common signs and symptoms are linked to anemia and pain. Other signs and symptoms are linked to organ complications from the disease.

Signs and symptoms of sickle cell disease include:

  • Fatigue (most common symptom)
  • Shortness of breath
  • Dizziness
  • Headache
  • Coldness in the hands and feet
  • Pale skin
  • Chest pain

Symptoms of Sickle Cell Trait

Most people with sickle cell trait have no symptoms and will not have any health complications. Occasionally people with sickle cell trait can have blood in their urine and very rarely experience complications of SCD, such as pain crises.

Under extreme conditions such as high altitude, severe dehydration, or very high intensity physical activity, red cells in people with SCT can become deformed or sickled. Although very rare, complications may include;

  • muscle breakdown (rhabdomyolysis)
  • reduced blood supply to the spleen (ischemia/infarction)
  • increased pressure in the eye (glaucoma)

Finally, a very rare form of kidney cancer (renal medullary carcinoma) has been associated with sickle cell trait.

Diagnosis

SCD and SCT is diagnosed with a simple blood test. It most often is found at birth during routine newborn screening tests at the hospital. However in resource-poor settings where there are no widely implemented newborn screening, SCD is usually diagnosed at later stages in the affected person’s life. In addition, SCD can be diagnosed before birth. Because children with SCD are at an increased risk of infection and other health problems, early diagnosis and treatment are important. You can call your local sickle cell organization to find out how to get tested.