Primary Immune Deficiency Treatment Consortium

Learn More - Severe Combined Immunodeficiency (SCID)


What is Severe Combined Immunodeficiency (SCID)?

Severe combined immunodeficiency (SCID) is a serious medical condition. Children born with SCID lack adequate immune protection against bacteria, viruses, and fungi and are prone to infections that would not normally cause illness in a person with intact and functional immune system.

Children with SCID are usually diagnosed within the first year of life due to the high frequency and severity of infections. Some of the common organisms that cause mild or no illness in children with healthy immune systems can cause severe infections in children with SCID.

Children affected by SCID can also become ill from live viruses present in some vaccines. These vaccines (such as Chickenpox, Measles, Rotavirus, oral polio and BCG, etc.) contain viruses and bacteria that are weakened and don’t harm children with a healthy immune system. In patients with SCID however, these viruses and bacteria may cause severe, life-threatening infections.

Who gets SCID?

SCID can affect either boys or girls of any race or ethnicity. Defects of at least 14 different genes may result in SCID. The most common form (about 45% of cases) occurs in boys and is inherited as an X-linked disease, meaning that females(mothers) may carry the abnormal gene for the disorder but don’t develop symptoms, whereas male children born to them carry the risk of  developing the clinical problems associated with the disease.. SCID is estimated to occur in approximately 1 out of every 50,000 to 100,000 births. (1) (Per [])

How is SCID Diagnosed?

The frequency and severity of infections are the most helpful clues that a patient may have a problem with their immune system. For patients with symptoms suggestive of SCID, the following tests can be helpful in making a definitive diagnosis:

What is the treatment for SCID?

Treatment for SCID may include the following: