In some cases the epiphyseal plate of the long bones of children closes too early. what might be the cause

Elevated levels of sex hormones can lead to early closing of these bones. When testosterone or estrogens are present, the bones can start to close sooner than usual, due to this process usually taking place during puberty. An accelerated pace of closure will be seen because the body is responding to the hormonal levels as if it were experiencing puberty at a younger age.