Severe Combined Immunodeficiency (SCID) in Children

What is SCID in children?

SCID is a very rare disease. It causes a child to have a very weak immune system (immunodeficiency). As a result, the child is unable to fight off even mild infections. The disease is also known as the “living in the bubble” syndrome because living in a normal environment can be fatal to a child who has it. Most often, this disease is passed down from parent to child (inherited).

SCID can be deadly. Children with SCID become very sick with infections, such as pneumonia, meningitis, and chickenpox. They can die before they reach their first birthday. However, treatments are available that can be successful.

What causes SCID in a child?

Many genetic problems can cause SCID. These problems make the white cells in the blood (T and B cells) less able to fight infection. The child's immune system has trouble defending the body against bacteria, viruses, and fungi.

There are several types of SCID. The two most common types are classical X-linked and ADA deficiency.

What are the symptoms of SCID in a child?

Symptoms of SCID usually start within the first year of a child’s life. Below are the most common symptoms of SCID. But symptoms can occur a bit differently in each child.

Usually, the child will have many serious infections, life-threatening infections, or both. The infections are not easily treated. And medicines to treat the infections don't work well. Common infections include:

• Pneumonia.

• Repeated ear infections.

• Meningitis.

• Blood infection.

• Chronic skin infections.

• Yeast infections in the mouth and diaper area.

• Diarrhea.

• Liver infection (hepatitis).

How is SCID diagnosed in a child?

The health care provider will ask about your child’s symptoms and health history. They will give your child a physical exam. Your child may need multiple blood tests to help confirm the diagnosis.

How is SCID treated in a child?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how bad the condition is.

Treatment for SCID includes:

• Treating the current infection.

• Preventing germs and new infections.

• Fixing the immune system problem.

The best treatment for this disease is a bone marrow transplant, which offers a chance of a cure. In a bone marrow transplant, bone marrow cells are transplanted from a healthy person to the child. Bone marrow is the soft, spongy tissue found inside the bones. It helps blood cells form and is the place where the body stores blood cells.

A bone marrow transplant has the best chance of working if it is done during a child’s first three months of life. The goal of a bone marrow transplant is to help the child’s immune system work better. Cord blood may also be used for the transplant.

Researchers have had some success using gene therapy to treat SCID. However, gene therapy is still in the experimental stages.

Can SCID be prevented in children?

Since this disorder is inherited, parents of children with SCID should think about talking with a genetic counselor. The counselor can talk with you about genetic testing and family planning.

Key points about SCID in children

• SCID is a disease that is passed on from parents to children (inherited).

• It is a very rare, life-threatening disease.

• The disease causes a child to have a very weak immune system.

• The best treatment for this disease is a bone marrow transplant.

• Parents of children with SCID should talk with a genetic counselor about genetic testing and family planning.

Next steps

Tips to help you get the most from a visit to your child’s health care provider:

• Know the reason for the visit and what you want to happen.

• Before your visit, write down questions you want answered.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

• Ask if your child’s condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if your child does not take the medicine or have the test or procedure.

• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.