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dwarfismColumbia Encyclopedia entry: dwarfism
Dwarfism, condition in which an animal or plant is less than normal in size and lacks the capacity for normal growth. Dwarfism is deliberately produced and perpetuated in certain species (e.g., in breeding miniature dogs and cultivating dwarf plants). Among humans, dwarfism usually results from a combination of genetic factors and endocrine malfunction. It can also be caused, however, by acquired conditions, such as kidney disease. Pituitary dwarfism is caused by an insufficiency of the pituitary growth hormone (hypopituitary dwarfism). Typically, the pituitary dwarf stops growing in early childhood but retains normal body proportion, mental capacity, and sexual development. Pharmaceutical companies are cloning human growth hormone to stimulate growth in children afflicted with hypopituitary glands. This type of dwarf, who is completely normal except for size, is commonly called a midget. Cretinism is a type of dwarfism accompanied by mental retardation and distortion of the body, resulting from an insufficiency of thyroid hormone. Unlike cretinism and pituitary dwarfism (which are thought to be caused by a combination of heredity and endocrine malfunction), achondroplastic dwarfism is the result of a completely hereditary, dominant genetic trait. Typically, the growth of the limbs is stunted, but the size of the trunk and mental capacity are normal. Humans who range in height from 2 to 4 ft (5.08–10.16 cm) are generally classified as dwarfs. However, small size that is an inherited characteristic of race (such as among African Pygmies) is not considered to be dwarfism since the individuals in such groups are physiologically normal.
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Wikipedia search results for: Dwarfism
From Wikipedia, the free encyclopedia
Dwarfism is short stature resulting from an abnormal medical condition. It is sometimes defined as an adult height of less than 4 feet 10 inches, although this definition is problematic because short stature in itself is not a disorder.
Dwarfism can be caused by about 200 distinct medical conditions, such that the symptoms and characteristics of individual dwarfs vary greatly. In the United States, people with dwarfism are often called little people.
Disproportionate dwarfism is characterized by one or more body parts' being relatively large or small in comparison to those of a normal adult, with growth abnormalities in specific...more »
Columbia Encyclopedia search results: dwarfism
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- growth hormone
Growth hormone or somatotropin, glycoprotein hormone released by the anterior pituitary gland that is necessary for normal skeletal growth in humans (see protein). Evidence suggests that the s...
- Flores, island, Indonesia
Flores, island, 6,627 sq mi (17,164 sq km), E Indonesia, one of the Lesser Sunda Islands. Flores is heavily wooded, rugged, and mountainous, rising to 7,872 ft (2,399 m); there are active volc...
- pituitary gland
Pituitary gland, small oval endocrine gland that lies at the base of the brain. It is sometimes called the master gland of the body because all the other endocrine glands depend on its secreti...
