Gigantism
Gigantism,  also known as giantism, is a condition when growth and height are much above average.  Overactivity of growth hormone during childhood causes this condition in humans. The growth hormone is one of the hormones that is released from the interior pituitary gland. If a person has been exposed to very high level of growth hormones before their growth plates have merged during childhood for example, this can be lead to the condition of gigantism.