Gene Therapies

Seattle Children’s offers gene therapies to correct disease by delivering new genetic material to the body.

As part of a world-class academic pediatric hospital and pediatric research center, we combine top-notch expertise with relentless determination to give your child the best chance of a bright future.

What is gene therapy?

Some diseases happen because of changes in genes (pieces of DNA) that affect how the body makes proteins needed for good health. These genetic changes (called variants or mutations) can cause serious diseases and sometimes early death. Genetic changes may be present at birth, whether because they were passed from parent to child (inherited) or happened as the fetus developed during pregnancy. In other cases, the genetic changes happen during a person’s life.

Gene therapies can deliver new genetic material to the body to fix or bypass an existing genetic mutation, with the goal of correcting the disease. These therapies have greatly improved the quality of life and survival of some people with certain genetic diseases and cancer. Some of the new therapies are approved by the U.S. Food and Drug Administration (FDA). Others are being developed and studied in clinical trials.

Gene therapy is given by infusion or injection. The new genetic material can be delivered to the target cells of the body in varied ways, depending on the underlying disease and which cells need to be targeted. Sometimes, new genetic material is delivered directly to the body by the hollow shell of a virus or by DNA that contains precise gene-editing tools. This is called in vivo gene therapy. 

Other times, specific cells are collected from a patient and the known genetic mutation is corrected in a very specialized lab. These corrected cells are then given back to the patient to control that disease. This is called ex vivo gene therapy (PDF). The gene therapies for sickle cell disease and thalassemia are examples of this type of therapy.

Finally, a patient’s own immune cells can be genetically modified to turn them into powerful fighters against cancer and other diseases. This type of therapy is called CAR T-cell immunotherapy and is referred to as a cell therapy. It uses a specific immune cell (a white blood cell called a T cell) that is collected from the patient’s blood. The T cells are genetically modified in the lab and returned to the patient by an infusion. CAR stands for chimeric antigen receptor.

Conditions We Treat

We offer gene therapies for certain blood disorders, neuromuscular conditions and cancer, such as:

• Sickle cell disease
• Thalassemia
• High-risk acute lymphoblastic leukemia (ALL)
• Duchenne muscular dystrophy (DMD)
• Spinal muscular atrophy (SMA)

FDA-Approved Gene Therapies We Offer

After a full assessment, Seattle Children’s experts will recommend if gene therapy is the best choice for your child at this time. We see patients at Seattle Children’s hospital campus in Seattle. We offer these gene and cell therapies approved by the U.S. Food and Drug Administration (FDA):

Blood diseases

• Casgevy for people 12 years and older with transfusion-dependent beta thalassemia or with sickle cell disease and frequent pain episodes (called vasoocclusive crises or VOCs). Gene therapy modifies a child’s own blood-forming stem cells to help their bone marrow make healthier red blood cells. This therapy may put an end to pain episodes for patients with sickle cell disease. People with beta thalassemia may be able to live without regular blood transfusions.
• Lyfgenia for people 12 years and older with sickle cell disease and frequent pain episodes (vasoocclusive crises or VOCs). Gene therapy adds a working gene to a child’s own blood-forming stem cells to help their bone marrow make healthier red blood cells. Your doctor will help your family decide which of the FDA-approved gene therapies may be best for your child.
• Zynteglo for people 4 years and older with transfusion-dependent beta thalassemia. Gene therapy adds a more functional gene to a child’s own blood-forming stem cells to help their bone marrow make healthier red blood cells. Patients may be able to live without regular blood transfusions. Your doctor will help your family decide which of the FDA-approved gene therapies may be best for your child.
• Kymriah for children and young adults with B-cell acute lymphoblastic leukemia (ALL) that has not responded to treatment or has returned (relapsed) after treatment. A child’s own T cells (immune cells) are reprogrammed into CAR T cells that can better target and destroy B cells, including those with cancer. The CAR-T cells multiply in the body and can keep fighting any new cancerous B cells as long as they are present. Learn more about CAR T-cell immunotherapy.

Neuromuscular diseases

• Elevidys for patients 4 years and older with Duchenne muscular dystrophy (DMD) who can walk and have certain mutations in the DMD gene. Gene therapy transfers a smaller version of the DMD gene to the muscles. This helps improve muscle health and slow worsening of the disease. It is given as a single IV infusion.
• Zolgensma for children under age 2 with spinal muscular atrophy (SMA) who have mutations in their SMN1 gene. Gene therapy transfers a working form of the SMN1 gene to nerves of the brain and spinal cord to improve muscle strength. This gene therapy is given as a single IV infusion.
• Itvisma for children over 2 years old with spinal muscular atrophy (SMA) who have changes in their SMN1 gene that prevent their body from making enough SMN protein. The therapy delivers a healthy copy of the SMN1 gene to your child’s nerve cells. This helps their body make more SMN protein, which is needed to keep the nerves that control movement working properly. It is given as a one-time infusion into the cerebrospinal fluid (CSF).

In addition to FDA-approved gene therapies, Seattle Children’s physician-scientists are developing new approaches offered in research studies called clinical trials.