Dwarfism, is a condition of short stature, and occurs in all organisms. In humans, dwarfism is defined as having adult height of less than 4 feet 10 inches, although these criteria differ. Some people are taller than five feet and are still dwarves. Dwarves have normal intelligence and life span. Dwarfism is of two types, proportionate and disproportionate, where the former is characterised by all the body parts being short, but in proportion, the latter is characterised by an average torso with short arms, or short torso with average arms. A type of dwarfism called Achondroplasia, is the reason of 70% cases of dwarfism. This occurs in 1 in 15,000 to 1 in 40,000 people, so is quite rare.