Idiopathic Adolescent Acute Neurodegeneration or IAAN for short (also known as Everhart's disease, named after its first fatal victim), is a fatal disease affecting children between the ages 8-13. Over 98% of the USA's children population died from this disease. Life for the surviving 2% of children was more than torture.
IAAN was known to not have any specific symptoms. The only real symptom was death without warning. The 2% that survived IAAN were given powers.
The cause of IAAN is Agent Ambrosia, a chemical that was released into food and water supplies by the US government as a way to neutralize potental chemical and biological terrorist attacks. During the development of Agent Ambrosia, men, women, children and even those who were pregnant were tested for abnormalities, and none were found until after the births of children post-Ambrosia exposure. The children showed no symptoms until the onset of puberty, upon which the children either died or developed psionic abilities.