Severe Combined Immunodeficiency 101

Was your child recently diagnosed after undergoing newborn screening for SCID, or were you referred to further testing for SCID? If so, here is some basic information about SCID (Severe Combined Immunodeficiency), along with some resources on where to get more information and stay educated.

Something many people don’t realize is that SCID is actually a group of conditions that cause problems in a person’s immune system. Currently, there are 14 forms of SCID that have been identified all related to abnormalities in infection fighting cells. The result of this is that your child is more prone to getting sick and contracting infectious diseases.

When should they test for SCID?

Only a certain number of states actually screen for SCID, however there are additional warning signs that parents can look out for and then request that their child be screened. If your child has any of the following, it may be an indicator of SCID:

Recurrent infections
Failure to thrive as a result of recurrent infections
Chronic diarrhea

How do they test for SCID?

In certain states they will test for SCID via newborn screening where a drop of blood is taken from the baby’s heel and run through a series of diagnostic tests. If those diagnostic tests come up with abnormal results, the doctor may ask you for additional testing. It is possible that your baby will go through a TREC test, designed to determined whether or not your child has SCID. According to the

Immune Deficiency Foundation

, “TREC are circular DNA molecules formed within T-cells developing in the thymus. TREC DNA circles are measured by a technique called polymerase chain reaction (PCR). Normal infant blood samples have one TREC per 10 T-cells, reflecting the high rate of new T-cell generation early in life. Infants with SCID lack TREC altogether.”