The genetic defect keeps the body from properly dealing with "errant" immune cells that it normally eliminates by a process called immunological tolerance. These immune cells then attack the insulin-producing beta cells in the pancreas, mistaking them as foreign invaders.

An estimated 1 million people in the United States have type 1 diabetes. Their pancreatic beta cells can no longer make insulin. Without this crucial hormone, their body cannot convert food into energy. To sustain life, they must get insulin through injections. The disorder can emerge in childhood, adolescence and even appear in adulthood, but the genetic stage is set beforehand.

T-cells play a key role. They are part of the highly complex array of immune cells that normally work together to fight invaders such as bacteria or viruses, adapting specifically to each new invader. Formed in the thymus gland, T-cells begin as "precursor" cells and mature -- during this time, receptor sites on their outer membrane are shaped to dock with each invader and destroy it. DiGeorge syndrome reflects a clinical phenotype now recognized by its underlying genetic diagnosis, chromosome 22q11.2 deletion syndrome, which is associated with multisystem involvement and variable immune defects among patients. Updated genetic and molecular techniques now allow for earlier identification of immune defects and confirmatory diagnoses, in this disorder with life-long clinical issues.

Regards

John
Editorial Assistant
Immunogenetics Open Access