What Causes Sickle Cell Disease?

Sickle cell disease is caused by inherited changes in a haemoglobin gene, which can make red blood cells become rigid and sickle-shaped. Haemoglobin is the red-cell protein that carries oxygen. The altered haemoglobin can cause red cells to break down sooner than usual and, during some episodes, obstruct small blood vessels. The condition is present because of genes inherited from biological parents; it is not caused by food, exercise, stress, or anything a person did.

A person has two copies of the gene involved in haemoglobin production, with one copy inherited from each biological parent. Disease can occur when a child inherits sickle haemoglobin changes in a combination that affects red-cell shape and function. A person who inherits one sickle haemoglobin change and one usual haemoglobin copy may have sickle cell trait, also called carrier status. Carriers generally do not have sickle cell disease, but they can pass the changed gene to a child. Different inherited haemoglobin changes can produce different forms of the condition, so a family history alone cannot identify the exact type.

When sickle-shaped cells break down, anaemia can develop. When they block blood flow, a person may experience episodes of pain or other complications. Fatigue, joint pain, or pale skin can occur for several medical reasons and do not, by themselves, show that someone has sickle cell disease.

If sickle cell disease or carrier status may run in your family, discuss testing with a clinician. A blood test can examine haemoglobin and help identify sickle haemoglobin or another haemoglobin variant. The result may need interpretation alongside symptoms, family history, and the person’s age and health. Testing can be relevant before pregnancy, during pregnancy, or when a child has symptoms or an abnormal screening result.

Premarital screening may help couples understand whether they carry inherited blood conditions and what genetic counselling could add. If both partners carry a relevant haemoglobin change, a clinician or genetic counsellor can explain possible inheritance patterns and available choices in clear, personal terms.

Arrange a medical appointment if you have a family history of sickle cell disease, have been told you may carry a haemoglobin change, or have symptoms that need an explanation. Seek urgent care for severe or unusual pain, difficulty breathing, chest pain, sudden weakness, confusion, a seizure, or a high fever, particularly if you already have sickle cell disease. These symptoms can signal a complication that needs prompt assessment rather than confirming the cause on their own.

You could ask: Which haemoglobin test is appropriate for me? Does my result show sickle cell disease, sickle cell trait, or another haemoglobin variant? Should a relative or partner be tested? If I am planning a pregnancy, would genetic counselling help? What symptoms should prompt urgent care in my situation?