Pediatric Severe Combined Immunodeficiency (SCID)

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.

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.

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.

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.

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)

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.