The correct answer is Deletion.
DiGeorge syndrome, more commonly considered as 22q11.2 deletion syndrome. It refers to an ailment resulting when a small segment of chromosome 22 is missing. This deletion leads to poor development of many systems of the body.
The medical issues generally associated with 22q11.2 deletion syndrome involve poor immune system function, heart defects, a cleft palate, delayed development with emotional and behavioral issues, and issues associated with diminished levels of calcium in the blood.