A child born with severe combined immunodeficiency (SCID), does not have an immune system that works properly. The immune system is made up of cells in the body that protect a person from sickness. A child with SCID doesn’t have that protection. Illnesses like the flu or even the common cold can make a child with SCID extremely sick and could even be fatal.
See answers to some commonly asked questions such as What causes SCID? And Does a child inherit SCID from parents through their genes?
There are about 20 different defects in the genes that can cause SCID. Each one of these genetic defects is considered a type of SCID. Most types of SCID are considered typical SCID, characterized by low or no T cells and a non-functional immune system.