WHAT’S BEHIND BETA
(β)-THALASSEMIA?

β‑thalassemiaa genetic blood disorder that reduces or eliminates the production of β‑globin affects your body at the genetic level. To understand more about what is behind the disease, it’s important to learn about the role that genes play in how your body works.

Where to Start: Cells, Genes, Proteins, and Your Body

Cells are the building blocks of all living things. Each and every one of us is made of cells. Inside cells is DNAa material that is in almost all living things that carries genetic information, which tells the cell what to do.

Genesa sequence of DNA responsible for controlling inherited traits are made of DNA. They are like an instruction manual for your body. Some genes have a very important job to do because they contain instructions that tell each cell to make Proteinsthe working component of your cells that is required for the structure, function, and regulation of your body’s tissues and organs.

Proteins are workers in the body that are made by cells. Proteins are required for the structure, function, and regulation of your body’s tissues and organs.

Red blood cells

Cells

Genes are made of DNA

DNA/Genes

Proteins are workers in the body that are made by cells

Protein

Proteins are required for the structure, function, and regulation of your body's tissues and organs

Organs/Body

In order to work properly, your body relies on cells, genes, and proteins to work together. Explore the sections below for a closer look.

To better understand how genes and proteins work together, it may be helpful to look at an example that is not related to β‑thalassemia. One example of how genes and proteins work together is eye color.

Proteins create an eye color that is unique to you (brown, hazel, gray, blue, etc.) based on the instructions from your unique genes. In other words, genes instruct proteins to influence the expression of a physical Traitan inherited characteristic  (like eye color).

People receive genes from their parents. This is why children often look like their parents—they share physical traits (and other characteristics) from their genes.

It’s easy to see why your genes are so important, since they are responsible for creating the proteins that tell your body how to work, look, and function.

Genes usually come in pairs: one copy of the gene from your mother, and one copy of the gene from your father. You may see a pair of genes written down as two letters.

In the diagram, the genes are represented by the letters A and B. Each child receives a unique pair of these letters, one from each parent. This pair of letters is called a Genotypeyour genetic makeup for any trait, which may be labeled with a pair of letters, each representing the copy of a gene inherited from one of your parents.

A genotype can be used to describe the general way a characteristic you inherit will show up in you. However, it is important to remember that your genes are unique to you. Even if you share the same genotype with other people, the inherited characteristic may not show up in the same way.

Gene and genotype diagram

Red Blood Cellshemoglobin-containing cell that carries oxygen throughout your body play an important role in your body. Their job is to carry oxygen from the lungs to the cells throughout your body. Oxygen is used to release energy and support your body's essential functions.

Like all cells, red blood cells rely on a protein within the cell to do the actual work of carrying the oxygen. In red blood cells, this protein is called Hemoglobina protein in your red blood cells that helps carry oxygen throughout your body; healthy adult hemoglobin contains iron and a balanced amount of β‑globin and α‑globin. The hemoglobin does the actual work of carrying oxygen throughout your body. When red blood cells are healthy, each cell is densely packed with hemoglobin. 

Red blood cells and hemoglobin

The formation of hemoglobin starts with special cells called  Blood Stem Cellsan immature cell that has the potential to develop into all types of blood cells, including white blood cells, red blood cells, and platelets. These cells are most often found in the bone marrow. Blood stem cells form all types of blood cells, including red blood cells, white blood cells, and platelets. As blood stem cells become red blood cells, the genes inside the cells provide instructions to build hemoglobin.

Hemoglobin is made up of four smaller proteins: two beta (β)‑globin proteins and two alpha (α)‑globin proteins. There must be an equal balance of β‑globin and α‑globin in order for adult hemoglobin to form properly.

Each of the four proteins also includes iron. Iron is important because it holds onto oxygen so that it can be delivered to your body.

WHAT'S BEHIND β‑THALASSEMIA?

β‑thalassemia is a genetic diseasea disease that is caused by a genetic change caused by a change in a specific gene called the HBB gene.

The instructions from the HBB gene create β‑globin (a part of hemoglobin). With the change in the HBB gene, the instructions for β‑globin are incorrect and your body produces reduced or no β‑globin. This affects how your red blood cells work. 

Without the correct amount of β‑globin, there is an excess amount of α‑globin, which clumps together and causes your red blood cells to die early. Additionally, less β‑globin means that less hemoglobin can form properly, causing your red blood cells to be smaller and become abnormally shaped. Due to these problems with your red blood cells, you do not have enough healthy red blood cells, which carry oxygen to your body to meet its needs; this condition is called anemiaa condition where there aren’t enough healthy red blood cells to carry adequate oxygen to the body's tissues.

Healthy red blood cell

When red blood cells are healthy, each cell is densely packed with hemoglobin.

HEMOGLOBIN

β-THALASSEMIA RED BLOOD CELL

Beta Thalassemia is a genetic disease caused by a change in a specific gene called the HBB gene.
Why is this important to know? Understanding the role that genes and proteins play in your body can help you better understand the changes to your body from β‑thalassemia.

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The Understanding Beta (β)‑Thalassemia Brochure can help you learn more 
about β‑thalassemia at the genetic level.

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