What Causes Severe Combined Immunodeficiency (SCID)?

Severe Combined Immunodeficiency (SCID) is a life-threatening condition where the body's immune system is unable to function properly. For years, scientists have been working to understand what causes this syndrome, and recent advances in molecular biology and the Human Genome Project have significantly contributed to our understanding of SCID.

According to research, SCID can be caused by mutations in at least 10 different genes (Table 1). While it is likely that there are other causes yet to be discovered, scientists have made significant progress in identifying several fundamental causes of this condition over the past decade. In fact, a second fundamental cause of human SCID was found as recently as 1993, with the discovery of the molecular basis of X-linked human SCID.

One of the first discovered molecular causes of human SCID is adenosine deaminase deficiency, which was reported in 1972. Since then, scientists have noted differences in inheritance patterns for SCID, including an X-linked recessive mode of inheritance in some families and an autosomal recessive mode of inheritance in others. This suggests that there are multiple causes of this fatal syndrome.

In recent years, researchers have identified several key components of the immune system that can cause SCID when mutated. These include cytokine receptor chains or signaling molecules, five genes necessary for antigen receptor development, adenosine deaminase - a purine salvage pathway enzyme, and CD45, a phosphatase. In fact, a recent study published in this issue of the Journal of Clinical Investigation describes how complete deficiency of the CD3ε chain of the T cell antigen receptor/CD3 complex can cause human SCID.

Overall, SCID is a syndrome characterized by the absence of T cells and adaptive immunity, which can result from mutations in multiple genes that encode components of the immune system. Further research is needed to fully understand the causes of this condition and develop effective treatments for those affected.

What causes scid