Dwarfism is defined as a person whose adult height does not exceed four feet ten inches resulting from a genetic or medical condition. The term dwarf, little person, or a person of short stature are socially acceptable terms for people with this condition. There are two different categories of dwarfism disproportionate dwarfism and proportionate dwarfism. Achondroplasia is the most common type of disproportionate dwarfism, while a relatively common type of proportionate dwarfism is growth hormone deficiency. Achondroplasia and growth hormone deficiency have very different causes, symptoms, treatments, and complications.
Disproportionate dwarfism is when the person’s body is not proportional. Some parts are smaller than average size, some are average size, while others are above average size. Most commonly the little person has an average size trunk, smaller-than-average-size limbs, and above average size head. However, sometimes a little person has a smaller-than-average size trunk, average size limbs, and above average size head. Disproportionate dwarfism is caused by skeletal dysplasia. The causes of these types of dwarfism prevent the development of bones because of a genetic mutation that occurred spontaneously or was inherited.
The most common type of disproportionate dwarfism is achondroplasia. Achondroplasia little people are characterized by an average size trunk, shorter than average size arms and legs, especially the upper arms and legs, shorter than average fingers, limited mobility at the elbow joints, a larger-than-average head, a flattened nose bridge, a protruding jaw, crowded and misaligned teeth, bowed legs, swayed lower back, flat, short, broad feet, “double-jointedness,” and an average adult height of four feet tall. This occurs in about one out of every 26,000 to 40,000 births. There is no treatment for achondroplasia. Some medical complications that little people with achondroplasia must encounter include late development of gross motor skills, increased chance for ear infections, breathing problems, weight problems, the curvature of the spine, bowed legs, joint stiffness, arthritis, lower back pain or numbness in the legs, and crowding of the teeth. Surgery and other medical interventions are common in a little person’s life to help minimize these medical complications, increase the person’s mobility, and increase the quality of life.
In contrast, proportionate dwarfism is when the person’s body is proportional. Their body parts are small, but all to the same degree. Common causes of proportionate dwarfism are metabolic disorders and hormonal disorders.
A relatively common type of proportionate dwarfism is growth hormone deficiency. Growth hormone deficiency in little people is characterized by a height below the third percentile on standard growth charts, a growth rate slower than expected and delayed or no sexual development. The cause of growth hormone deficiency is unknown. There is a treatment for growth hormone deficiency and this is injections of growth hormone given daily. The major side effects are headaches, fluid retention, muscle and joint aches, and finally slippage of the bones at the hip. Early diagnosis of this deficiency is extremely important. The earlier the diagnosis the better chance there is for the child to grow to near normal adult height. Unfortunately, this treatment doesn’t work for all children. If left untreated or if the treatment doesn’t work then the person will be of short stature and have a delayed puberty. Growth hormone deficiency can occur at the same time as deficiencies of thyrotropins, vasopressin, gonadotropins, and ACTH since all these are produced or controlled by the pituitary gland.
The most common type of disproportional dwarfism, achondroplasia, and a common type of proportionate dwarfism, growth hormone deficiency, have very different causes, symptoms, treatments, and complications.
References
http://www.nlm.nih.gov/medlineplus/ency/article/001176.htm
http://children.webmd.com/dwarfism-causes-treatments
http://www.lpaonline.org/faq-
http://www.nlm.nih.gov/medlineplus/dwarfism.html
http://rarediseases.info.nih.gov/gard/1988/dwarfism/resources/1
http://www.mayoclinic.com/health/dwarfism/DS01012/DSECTION=symptoms
