In 2005, Insulin-like Growth Factor I was approved by the FDA for treatment of severe Growth Hormone Insensitivity Syndrome. This syndrome is usually caused by an abnormality in the growth hormone receptor and is very rare (there are probably no more than 500 people in the world with this condition). This medication is marketed under the name Increlex and is given as a once- or twice-daily injection. There has been some interest in studying whether this medication might be helpful in other situations in which growth hormone has been ineffective.