A dwarf is a person of short stature - under 4' 10" as an adult. More than 200 different conditions can cause dwarfism. A single type, called achondroplasia, causes about 70 percent of all dwarfism. Achondroplasia is a genetic condition that affects about 1 in 15,000 to 1 in 40,000 people. It makes your arms and legs short in comparison to your head and trunk. Other genetic conditions, kidney disease and problems with metabolism or hormones can also cause short stature.
Dwarfism itself is not a disease. However, there is a greater risk of some health problems. With proper medical care, most people with dwarfism have active lives and live as long as other people.