Dwarfism, also known as short stature, occurs when an organism is extremely small. In humans, it is sometimes defined as an adult height of less than 147 centimetres (4 ft 10 in), regardless of sex, although some individuals with dwarfism are slightly taller. Disproportionate dwarfism is characterized by either short limbs or a short torso. In cases of proportionate dwarfism, both the limbs and torso are unusually small. Intelligence is usually normal, and most have a nearly normal life expectancy.