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Facts About Sickle Cell Disease

Sickle Cell Disease (SCD) is the most common genetic blood disorder world-wide. Despite this, many people – including doctors, nurses, and school teachers in Alberta – aren’t familiar with this disease. Misinformation and misunderstanding can be very dangerous for patients living with this disease.

Cause of SCD

SCD is a group of inherited blood disorders. The presence of SCD is known at birth and can be diagnosed with a simple blood test. It is a life-long illness that is managed in patients with regular medical care and on-going treatment. It is not contagious nor transmitted through blood.
The disease is only passed on genetically when offspring receive the sickle cell trait from both biological parents. Therefore, a child can only be diagnosed with SCD when he/she inherits two abnormal hemoglobin genes – one from each parent. In cases where a child inherits only one sickle cell gene, he/she becomes a carrier of sickle cell trait; carriers rarely display signs of SCD, but can pass the trait on to their children and future generations.

Types of SCD

There are several types of SCD. The most common types of SCD are: HbSS (sickle cell anemia), HbSC, and HbS beta thalassemia. The type of SCD will affect the severity of symptoms. HbSS sickle cell anemia is the most severe form of the disease.

Genetic Counselling

Sickle cell anemia can only be inherited if both parents carry the sickle cell “S” gene. Therefore, genetic counseling is recommended for all carriers of the sickle cell trait to help individuals understand their risk. Prenatal screening is also available by sampling some of the amniotic fluid surrounding the unborn baby.

Sickle Cells

Hemoglobin allows red blood cells carry to oxygen to all parts of the human body. Most red blood cells are round in shape – like a disc – so they can easily flex through blood vessels of all sizes.
Sickle cells are not like normal red blood cells. Sickle cells have abnormal hemoglobin which causes red blood cells to become misshapen, hard and sticky. These C-shaped cells get their name from a farm tool called the “sickle”, which is a similar shape. They have difficulty delivering oxygen throughout the body because they often get stuck in tiny blood vessels and clog blood flow.
Any activity that decreases the amount of oxygen available in the body can abruptly change smooth, round red blood cells into rigid, sticky, sickle-shaped cells in SCD patients causing an immediate pain crisis <link to Living with Sickle Cell Disease page>.
Sickle cells die quicker than healthy, red blood cells. For this reason, red blood cells in someone living with SCD are in constant short supply. A sickle cell patient will tire more easily, become dehydrated more quickly, and is prone to frequent pain crises and serious infection.

Sources: Centers for Disease Control and Prevention, Facts About Sickle Cell Disease, 2016
Mayo Clinic, Sickle Cell Anemia, 2017