Anton's Key

From Orson Scott Card Wiki

Anton's Key is a genetic modification that afflicts Julian 'Bean' Delphiki and four of his nine children. One who has this is said to have "Anton's Key turned." The genetic modification causes giantism, extremely high intelligence and a virtually unlimited capacity for learning. Both are caused by a slow, but constant and unstoppable growth from birth of both body and, more remarkably, brain. Children with Anton's Key turned will be born prematurely, and, despite low birth weight and shorter gestation period, will not require any extra attention as most premature babies do. All of the normal human growth milestones are accelerated, including, but not limited to, toilet training, walking, talking and puberty (except for the growth spurt).

As the child grows, the immense size of the body causes circulation difficulties for the heart. The heart is forced to pump blood through a network of arteries and veins much larger than the average human's network. In the process, the subject will eventually experience congestive heart failure, causing death. As a result, persons in whom Anton's Key has been turned typically do not live past their twentieth birthday.

The scientist who created it was placed under a mental ban so that others would be unable to replicate his work; however, Volescu did get ahold of the information and created Bean.