<unk>  <unk>  refers to extreme<unk><unk>  that does not have a diagnostic explanation<unk>  designates a condition that is unexplained or not understood) after an ordinary growth evaluation. The term has been in use since at least 1975 without a precise percentile or statistical definition of "extreme".
In 2003 Eli Lilly and Company offered a more precise definition of<unk>  when the pharmaceutical company submitted clinical trial data to the U.S. Food and Drug Administration (FDA) requesting approval to advertise their brand of growth hormone for the treatment of<unk> . They proposed a definition of a height more than 2.25 standard deviations below mean, roughly equal to the<unk> est 1.2% of the population.
Other researchers have described a cutoff of 2.0 standard deviations.
Idiopathic short stature
Constitutional growth delay
Congenital adrenal hyperplasia
Hypothyroidism
Acromegaly
Hyperpituitarism
Hyperandrogenism
Hypopituitarism