Brenden Adams, a 13-year-old from Ellensburg, Wash., is already 7-feet, 3-inches tall, the Seattle Times reported Monday.
His bones, teeth and organs are growing at an abnormal pace because of an inverted chromosome 12.
"He gets sick and tired of Mom asking him, 'Brenden, are you OK?'" his mother, Debbie Enzell told the Times. "It has to be painful, but I can tell in his voice when he gets annoyed. He's like, 'Mom, I'll let you know.' He never complains. Never."
Researchers believe Brenden may be the only person in the world to grow so quickly.
Needless to say, Brenden’s height makes it difficult for him to do normal things, like ride in a car or play football.
Doctors are uncertain of his medical prognosis. Last year, Brenden had 12 molars removed and he underwent an experimental procedure to speed up puberty, fuse his growth plates and stop him from growing.
The procedure may have worked on his bones, but it is not clear whether his internal organs have stopped growing.
When Brenden had his spleen removed three weeks ago, it was the size of a football and extended from his chest to his pelvis.
Doctors are baffled as to why Brenden’s chromosome is inverted. Only two percent of the population has a balanced chromosomal inversion. This happens when cells divide during early stages of development.
In essence, one copy of Brenden’s12th chromosome is as if someone took a piece off of it, turned it around and then put it back. Geneticists now realize that in this process the HMGA2 gene was disrupted, which is crucial to growth.