What is Sickle Cell Disease?

Sickle Cell Disease

• Inherited red blood cell disorder causing abnormal hemoglobin
• Hemoglobin is a protein in the red blood cells that carries oxygen throughout the body
• Inherited means the disease is passed by genes from parents to their children
• SCD is not contagious (like a cold or infection)
• People with SCD inherit 2 abnormal hemoglobin genes (one from each parent)- one of them being hemoglobin S

Sickle Cells

• Red blood cells that contain normal hemoglobin are disc shaped (like a doughnut without a hole) which allows it to be flexible so they can move around through large and small blood vessels to deliver oxygen
• Sickle hemoglobin is not like normal hemoglobin. It can form stiff rods within the red cell, changing it to a crescent, or sickle shape
• Sickle cells are not flexible and can stick to vessel walls, causing blockage that slows or stops the flow of blood
• When this happens, oxygen can’t reach nearby tissues- causing attacks of severe pain (pain crises), organ damage

Prognosis of SCD

• Life long disease that affects multiple organs: Spleen, Brain, Eyes, Lungs, Liver, Heart, Kidneys, Penis, Joints, Bones, Skin
• Sickle cells don’t live long (10-20 days instead of 100-120 days) so patients have severe anemia
• In high income countries like US, life expectancy is 40-60 years
• Bone marrow transplant is the only cure so far but only very successful in a matched sibling donor

Inheritance

• When hemoglobin S gene is inherited from only one parent, and a normal hemoglobin gene is inherited from the other, a person has sickle cell trait
• People with trait are normally healthy
• If the child’s other parent also has sickle cell trait or another hemoglobin gene (like Thalassemia, hemoglobin C, hemoglobin D, Hemoglobin E), that child has a chance of having sickle cell disease (SCD)

Complications of SCD

• Newborn screening catches every child with SCD or trait (but this is only children born in the US)
• Painful swelling of hands and feet (called dactylitis)
• Fatigue, fussiness from anemia
• Yellowish color of skin, eyes from red cell breaking, liver disease, gallstones
• Pain in back, legs, arms, abdomen, chest, joint complications
• Shortness of breath, tired, dizzy
• Infection
• Acute chest syndrome
• Stroke
• Blindness
• Heart, Lung, Kidney disease, priapism (painful erections)
• Delayed growth, puberty due to anemia, depression, chronic pain, risky pregnancy