Sickle cell disease is an inherited blood disorder that affects how the body produces haemoglobin — the protein inside red blood cells that carries oxygen. In Canada, it is one of the most common serious genetic conditions, affecting people of all backgrounds. This article explains what sickle cell disease is, how it is diagnosed, what symptoms to watch for, and what treatment options are available.

What Is Sickle Cell Disease?

Normally, red blood cells are round and flexible. They move easily through blood vessels, carrying oxygen from the lungs to every part of the body. In people with sickle cell disease, the body produces an abnormal form of haemoglobin called haemoglobin S (HbS).

HbS causes red blood cells to become stiff and shaped like a crescent or sickle. These misshapen cells cannot move through blood vessels properly. As a result, they can block blood flow and reduce oxygen delivery to tissues and organs.

Haemoglobin is a protein that contains iron. It is found inside red blood cells and is responsible for transporting oxygen throughout the body. There are several types of haemoglobin. Foetal haemoglobin (HbF) is produced during pregnancy. After birth, it is gradually replaced by normal adult haemoglobin (HbA). Sickle cell disease occurs when genetic mutations replace HbA with the abnormal HbS.

How Genetics Play a Role

Sickle cell disease follows a clear pattern of inheritance. If a person inherits one normal haemoglobin gene and one HbS gene, they are called a carrier. Carriers typically produce 20–40% HbS but enough normal HbA to stay healthy. This is called sickle cell trait.

However, if a person inherits two copies of the HbS gene — one from each parent — their body produces 80–100% HbS and little or no normal haemoglobin. This person has sickle cell disease. Furthermore, people who inherit one HbS gene alongside another abnormal haemoglobin variant — such as haemoglobin C (HbC) or beta-thalassaemia — can also develop sickle cell disease. These combinations are called compound heterozygous conditions.

How Sickle Cell Disease Affects the Body

Inside the red blood cell, HbS molecules form rigid polymers when oxygen levels are low. These polymers distort the cell’s shape from a smooth disc into a sickle or crescent form. This change limits the cell’s ability to travel through small blood vessels.

Sickle-shaped cells can clump together and block tiny blood vessels. When this happens, the tissues beyond the blockage do not receive enough oxygen. Over time, this lack of oxygen causes serious damage to organs, bones, and other tissues throughout the body.

Why Anaemia Develops

Normal red blood cells live approximately 120 days. Sickle cells, in contrast, live only 10 to 12 days. The body cannot replace them fast enough. As a result, the total number of red blood cells drops, leading to anaemia — a condition where the blood does not carry enough oxygen to meet the body’s needs.

To compensate, the body releases immature red blood cells into the bloodstream. These immature cells are not as effective as healthy ones. Therefore, fatigue and weakness are common in people living with sickle cell disease. You can learn more about how blood disorders develop on the Health Canada website.

Symptoms of Sickle Cell Disease

The symptoms of sickle cell disease vary depending on age, the specific gene combination involved, and which organs are affected. Most people with the condition begin showing symptoms within the first year of life.

Common symptoms include:

  • Fatigue and anaemia — caused by the rapid breakdown of sickle cells

  • Pain crises — sudden episodes of severe pain in the chest, abdomen, joints, or bones

  • Dactylitis — painful swelling of the hands and feet, especially in young children

  • Bacterial infections — the spleen is often damaged, reducing the body’s ability to fight infections

  • Splenic sequestration — a rapid pooling of blood in the spleen, which can be life-threatening

  • Liver congestion — caused by blocked blood flow to the liver

  • Lung and heart damage — sickle cells can damage these vital organs over time

  • Leg ulcers — open sores on the lower legs, more common in older teens and adults

  • Bone damage — including avascular necrosis, where bones lose their blood supply and begin to die

  • Eye problems — damage to the blood vessels in the retina

Symptoms by Age Group

Infants with sickle cell disease often appear healthy in the first few months of life. This is because foetal haemoglobin (HbF) is still present and protective. As HbF is replaced by HbS over the first year, symptoms begin to appear.

Young children may experience fever, abdominal pain, painful hand and foot swelling, and bacterial infections such as pneumococcal pneumonia. Teenagers and young adults are more likely to develop leg ulcers, avascular necrosis, and eye damage. Adults often experience recurring episodes of pain from damage to bones, muscles, and internal organs.

For a comprehensive overview of sickle cell symptoms and complications, the Mayo Clinic’s guide to sickle cell anaemia is an excellent resource.

How Is Sickle Cell Disease Diagnosed?

Diagnosing sickle cell disease usually begins with a blood test. A doctor or lab technician examines a blood smear under a microscope. In a low-oxygen environment, the abnormal sickle-shaped cells become clearly visible. A solubility test can also detect abnormal haemoglobin S in the blood.

The most accurate diagnostic tool is haemoglobin electrophoresis. This test separates different types of haemoglobin by applying an electric charge. Because each type of haemoglobin protein carries a different electrical charge, they move at different speeds through the test field. This allows lab technicians to identify and measure exactly which types of haemoglobin are present in the blood.

Newborn Screening in Canada

In Canada, most provinces include sickle cell disease in their newborn screening programmes. A small blood sample is taken from the baby’s heel shortly after birth. Early detection allows families and healthcare providers to begin preventive care before symptoms appear.

In addition, prenatal diagnosis is possible before birth. Two procedures — amniocentesis and chorionic villus sampling (CVS) — can collect foetal cells for DNA analysis. These tests can confirm whether a baby has inherited the HbS gene. Families with a known history of sickle cell disease should speak with their family doctor or a genetic counsellor about these options.

Treatment Options for Sickle Cell Disease

There is no single cure for sickle cell disease for most patients, though a bone marrow transplant can be curative in select cases. However, effective treatments exist to manage symptoms, prevent complications, and improve quality of life.

Common treatment approaches include:

  • Hydroxyurea — a medication that increases foetal haemoglobin levels, reducing the number of sickle cells formed

  • Pain management — including over-the-counter and prescription pain relievers during pain crises

  • Antibiotics — to prevent and treat bacterial infections, especially in young children

  • Blood transfusions — to increase the number of healthy red blood cells and reduce complications

  • Folic acid supplements — to support red blood cell production

  • Vaccinations — pneumococcal and other vaccines are strongly recommended to reduce infection risk

  • Bone marrow or stem cell transplant — currently the only potential cure, though it is not suitable for everyone

Treatment plans are highly individual. A haematologist — a doctor who specialises in blood disorders — typically leads care. In Canada, most major cities have specialised haematology centres within hospitals covered under provincial health plans. Your family doctor can provide a referral to a specialist.

The World Health Organization’s fact sheet on sickle cell disease provides additional information on global treatment approaches.

When to See a Doctor

If you or your child has been diagnosed with sickle cell disease, regular check-ups with a family doctor or specialist are essential. Do not wait for a crisis to seek care. Ongoing monitoring helps catch complications early and keeps your treatment plan up to date.

Seek immediate medical attention — either from your family doctor, a walk-in clinic, or your nearest emergency department — if you or your child experiences any of the following:

  • Sudden severe pain that does not improve with usual pain medication

  • High fever, especially in young children

  • Difficulty breathing or chest pain

  • Sudden swelling of the abdomen

  • Stroke symptoms — sudden weakness, numbness, or difficulty speaking

  • Vision changes

  • Painful, prolonged erection (priapism) in males

In Canada, most provincial health plans cover visits related to sickle cell disease management. If you do not have a family doctor, a walk-in clinic can provide initial assessment and referrals. Always consult a qualified healthcare provider before making any changes to your or your child’s treatment plan.

Frequently Asked Questions About Sickle Cell Disease

What is the difference between sickle cell disease and sickle cell trait?

Sickle cell trait means a person carries one normal haemoglobin gene and one HbS gene. People with sickle cell trait are usually healthy and do not develop the full condition. Sickle cell disease occurs when a person inherits two abnormal haemoglobin genes, causing serious health problems.

Can sickle cell disease be cured?

A bone marrow or stem cell transplant is currently the only potential cure for sickle cell disease, but it is not suitable for all patients. Researchers are actively studying gene therapy as a future cure. In the meantime, treatments can effectively manage symptoms and prevent serious complications.

Is sickle cell disease common in Canada?

Sickle cell disease is one of the most common serious genetic blood conditions in Canada. It is more prevalent among people of African, Caribbean, Middle Eastern, and South Asian descent. Most Canadian provinces include sickle cell screening in their newborn testing programmes.

What triggers a sickle cell pain crisis?

A sickle cell pain crisis can be triggered by dehydration, cold temperatures, physical stress, illness, or low oxygen levels — for example, at high altitudes. Managing these triggers through lifestyle adjustments can help reduce the frequency of pain episodes. Always discuss personalised strategies with your healthcare provider.

How is sickle cell disease diagnosed in newborns in Canada?

Most provinces in Canada screen newborns for sickle cell disease shortly after birth using a heel-prick blood test. Early diagnosis allows doctors to begin preventive treatment before symptoms develop. If you have concerns about your newborn’s screening results, speak with your family doctor or paediatrician.

What foods or lifestyle habits help people with sickle cell disease?

People with sickle cell disease benefit from staying well-hydrated, eating a balanced diet rich in fruits, vegetables, and whole grains, and avoiding smoking. Regular check-ups and following a prescribed treatment plan are equally important. Always speak with your doctor or a registered dietitian before making major dietary changes.

Key Takeaways

  • Sickle cell disease is an inherited blood disorder caused by abnormal haemoglobin S (HbS).

  • It causes red blood cells to become sickle-shaped, blocking blood flow and reducing oxygen delivery to the body.

  • The condition leads to anaemia, pain crises, and damage to organs and tissues over time.

  • Most Canadian provinces screen newborns for sickle cell disease through provincial health programmes.

  • Diagnosis is confirmed through haemoglobin electrophoresis, blood smear testing, or prenatal DNA analysis.

  • Treatment focuses on managing symptoms, preventing infections, and improving quality of life. A bone marrow transplant may be curative for some patients.

  • Regular care from a family doctor and specialist is essential. If you suspect you or your child may have sickle cell disease, speak with your healthcare provider as soon as possible.