Dwarfism refers to a condition of extreme small size of an animal, or plant. Any type of marked human smallness could be termed dwarfism in older popular and medical usage. The term as related to human beings (the major subject of this article) is often used to refer specifically to those forms of extreme shortness characterized by disproportion of body parts, typically due to an inheritable disorder in bone or cartilage(body skeletal structures) development. ...

Dwarfism refers to a condition of extreme small size of an animal, or plant. Any type of marked human smallness could be termed dwarfism in older popular and medical usage. The term as related to human beings (the major subject of this article) is often used to refer specifically to those forms of extreme shortness characterized by disproportion of body parts, typically due to an inheritable disorder in bone or cartilage(body skeletal structures) development.

Forms of extreme shortness characterized by proportional body parts usually have a hormonal or nutritional cause. An example is growth hormone deficiency, once known as "pituitary dwarfism".The Little People of America (LPA) defines dwarfism as a medical or genetic condition that usually results in an adult height of 4'10" (147 cm) or shorter.

Examples or types include achondroplasia, osseous dysplasia, chondrodystrophy, and osteochondrodystrophy.The most recognizable and most common form of dwarfism is achondroplasia, which produces rhizomelic short limbs, increased spinal curvature, and distortion of skull growth. It accounts for 70% of dwarfism cases. Other relatively common types include spondyloepiphyseal dysplasia congenita (SED), diastrophic dysplasia, pseudoachondroplasia, hypochondroplasia, and osteogenesis imperfecta (OI). Severe shortness with skeletal distortion also occurs in several of the mucopolysaccharidoses and other body storage diseases.

The average adult height of male and females with dwarfism is 132cm and 123cm respectively. The average weight of an adult may range from 100 to 150 pounds (45-68 kg).