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Genetics of Sickle Cell
Sickle cell is a genetic, lifelong disease caused by an alteration in a gene that affects a person’s red blood cells.
Cells the basic building blocks of all living things
DNA the substance (or molecule) that carries genetic information in a human cell
Normal adult hemoglobin (HbA) healthy form of adult hemoglobin produced when there is no mutation in the HBB gene and it does not stick together to cause sickling

Sickle cell is a genetic, lifelong disease caused by an alteration in a gene that affects a person’s red blood cells. Learning about the role that genes play can help you and your loved ones better understand what causes the disease and its symptoms.
“I did not understand sickle cell [when I was younger]. I had less education about it...So being educated on what sickle cell is made it a lot easier for me to understand myself.”

— Aaron, Sickle Cell Survivor

Genetics 101:
Cells, DNA, Genes, Proteins, and Your Sickle Cell

Every living thing is made up of one or many building blocks called Cellsthe basic building blocks of all living things. The human body has trillions of cells, and they are divided into many different types including muscle cells, bone cells, red blood cells, and white blood cells.

All cells work together to keep us alive. They carry out functions like converting food to energy. Some of them provide structural support, giving our organs and our body shape and strength.

Inside each cell is DNAthe substance (or molecule) that carries genetic information in a human cell, which provides instruction for the growth and function of living things. It helps determine our physical characteristics, and it’s also the carrier of genetic information. 

All of your DNA is called a genome. Within the genome are many smaller sections of DNA called genes. Genes are like an instruction manual for your cells, and some genes provide instructions to make proteins.

Proteins are the workers of the cell. They perform a number of different functions within our bodies to keep us healthy, such as powering muscles, attacking invading bacteria, or delivering oxygen throughout the body. 

Your body relies on cells, DNA, genes, and proteins to work together to function properly.

Genes and Proteins

To better understand how genes and proteins work together, it’s helpful to think of genes as the blueprint for your body. Just as a blueprint provides instructions to build things in a house like walls and windows, your genes provide instructions for your body to create proteins that carry out different functions within the body. Each cell in your body relies on thousands of proteins to do their jobs properly to function correctly.

However, a change (mutation) in a gene’s instruction can cause a cell or protein to not function properly. Although not all changes cause disease, such as the genetic change that affects a person’s height, some do.

Check out the video to learn more about how genes and proteins impact the symptoms and complications of sickle cell.

Mechanism of Sickle Cell Disease Mechanism of Sickle Cell Disease

Mechanism of Sickle Cell Disease Mechanism of Sickle Cell Disease

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Red blood cells, hemoglobin, and the HBB gene

Blood is made up of four components including red blood cells, white blood cells, platelets, and plasma. It has several functions:

  • Circulating oxygen and nutrients throughout the body
  • Clotting blood to prevent blood loss
  • Carrying cells and antibodies to fight infection
  • Transporting and filtering waste through the kidneys and liver
  • Controlling body temperature

Red blood cells are the most common type of cell in blood. Their job is to carry oxygen from the lungs throughout the body and move carbon dioxide from your organs to your lungs. This cycle allows oxygen to fuel your organs by giving them the energy they need to function. 

There is a protein within red blood cells that picks up and carries oxygen throughout the body. This protein is called hemoglobin and is made up of four smaller protein subunits: two beta (β)‑globin proteins and two alpha (α)‑globin proteins. There must be a balance of both healthy beta‑globin and alpha‑globin in order for Normal adult hemoglobin (HbA)healthy form of adult hemoglobin produced when there is no mutation in the HBB gene and it does not stick together to cause sickling to work properly. 

Graphic depicting genetics and hemoglobin (HbA) Graphic depicting genetics and hemoglobin (HbA)
The instructions that make beta‑globin proteins are provided by the HBB gene. If there is a specific change (mutation) in the HBB gene, the instructions for beta‑globin are changed and cause your body to produce an abnormal form of beta‑globin, such as hemoglobin Sickle (HbS), which can cause your red blood cells to sickle. Having red blood cells with HbS can result in a person having sickle cell disease or carrying the sickle cell trait.
It’s important to remember that sickle cell is an inherited disease. This means that it is not contagious, and you can't catch it from other people like you can catch a cold or the flu. Learn more about inheriting sickle cell or having sickle cell trait.
Photo of Joyce, parent who care for someone living with sickle cell
 

We need to have more education. We need to have more easily accessible information. That’s what I wish I had more of, in a timely manner.

We need to have more education. We need to have more easily accessible information. That’s what I wish I had more of, in a timely manner.

JOYCE

Parent

What Can You Do?

Educating others in your community by sharing what you’ve learned about the role genes play in sickle cell can help spark change in their understanding of the disease. Learn more about why humans evolved to carry sickle cell trait by taking a closer look at the history of sickle cell

Every voice, no matter how big or small, can spark a conversation and action to help drive change for sickle cell. Sign up to stay connected through email with resources, support, ways to connect with others, and more information about sickle cell.

Recognizing how sickle cell impacts your life may help spark important discussions with others to bring changes in your care and the care of your loved ones. How does sickle cell affect you?