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Severe Combined Immunodeficiency (SCID) 

What is severe combined immunodeficiency? 

Severe combined immunodeficiency (SCID) is a group of diseases that affect genes related to the development and function of cells in the immune system. 

Onset of this condition occurs during infancy, and infants are unable to fight off diseases due to their weakened immune system. 

It occurs in one of every 100,000 people in the United States, and it is more common in those of Navajo, Apache, and Turkish ancestry. 

What are the symptoms of severe combined immunodeficiency?

Recurrent infections are the major symptoms of SCID. These infections are serious or life-threatening, and they do not respond well to medication. The most common infections include:

  • Pneumonia
  • Ear infections
  • Meningitis
  • Blood infections
  • Chronic skin infections
  • Yeast infections
  • Diarrhea
  • Hepatitis

What causes severe combined immunodeficiency?

There are multiple genes that have been associated with SCID. Mutations in these genes affect the T and B cells of the immune system, making it difficult for the body to fight infections. The specific gene that is mutated will influence the type of SCID one has. 

These mutations can also be inherited in different ways. The most common form of SCID is passed down in an autosomal recessive pattern, but there are also X-linked forms of the disease. 

How is severe combined immunodeficiency diagnosed?

Doctors tend to suspect SCID within the first year of a child’s life, due to recurrent infections. A physical exam and family and medical history can lead to a diagnosis, which needs to be confirmed through blood tests. 

Screening for SCID is common in many states across the U.S., so infants are often diagnosed soon after birth as well. 

What are the treatments for severe combined immunodeficiency?

Treatment for this condition requires immediate diagnosis and treatment of any infections. Preventing infections and avoiding germs is also important. 

Treating the malfunction in the immune system itself is the largest part of treatment. The best way to do so is a bone marrow transplant, which gives a chance for a cure. This procedure is the most successful if it is done within three months of birth. 

Enzyme replacement and gene therapies are being researched and improved, and they are now options for some forms of SCID. 

Where can I find out more about severe combined immunodeficiency?

Severe Combined Immunodeficiency Articles