Dwarfism can be caused by a number of conditions (approximately 300 of which are known). One of the most common is called achondroplasia. This genetic or congenital condition causes the body to be disproportionate with a normal sized torso, short arms and legs, an enlarged head, and prominent brow ridge. Intelligence is usually normal. Sometimes dwarves suffer from health problems related to their small size and have life spans that are usually shorter than their normal-sized peers. The gene for achondroplasia was located in 1994 by scientists at the University of California in Irvine.