|
HealthTales.com |
|
| Index of Diseases and Conditions: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
Down syndrome is a chromosomal condition that is associated with mental retardation, a characteristic facial appearance, and poor muscle tone (hypotonia) in infancy. People with this condition are at an increased risk for heart defects, digestive problems such as gastroesophageal reflux or celiac disease, hearing loss, and cancer of blood-forming tissue (leukemia). Additionally, some people with Down syndrome have reduced activity of the thyroid gland (hypothyroidism). The thyroid gland is a butterfly-shaped organ in the lower neck that produces hormones.
Some evidence indicates that Down syndrome is associated with an increased risk of Alzheimer disease, a degenerative disease of the brain that causes a gradual loss of memory, judgment, and ability to function. Although Alzheimer disease is usually a disorder of late adulthood, in people with Down syndrome the signs and symptoms can appear as early as age 30.
Down syndrome occurs in 1 in 800 to 1,000 births. The risk of having a child with Down syndrome increases as a woman gets older.
Down syndrome is related to chromosome 21.
Most cases of Down syndrome result from trisomy 21, which means each cell in the body has three copies of chromosome 21 instead of the usual two copies. The extra genetic material disrupts the normal course of development, causing the characteristic features of Down syndrome. Although the connection between Down syndrome and Alzheimer disease is unclear, researchers believe that an extra copy of a particular gene on chromosome 21, the APP gene, may account for the increased risk.
A small percentage of Down syndrome cases occur when only some of the body's cells have an extra copy of chromosome 21. These cases are called mosaic Down syndrome.
Although uncommon, Down syndrome also can occur when part of chromosome 21 becomes attached (translocated) to another chromosome before or at conception. Affected people have two copies of chromosome 21, plus extra material from chromosome 21 attached to another chromosome. These cases are called translocation Down syndrome.
Most cases of Down syndrome are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 21. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 21 in each of the body’s cells.
Mosaic Down syndrome is also not inherited. It occurs as a random error during cell division early in fetal development. As a result, some of the body’s cells have the usual two copies of chromosome 21, and other cells have three copies of the chromosome.
Translocation Down syndrome can be inherited. An unaffected person can carry a rearrangement of genetic material between chromosome 21 and another chromosome. This rearrangement is called a balanced translocation because there is no extra material from chromosome 21. Although they do not have signs of Down syndrome, people who carry this type of balanced translocation are at an increased risk of having children with the condition.
In medicine, the term '''syndrome''' is the association of several clinically recognizable features, sign (medicine), symptoms, phenomena or characteristics which often occur together, so that the presence of one feature alerts the physician to the presence of the others. In recent decades the term has been used outside of medicine to refer to a combination of phenomena seen in association. The term ''syndrome'' derives from the Greek and means literally "run together," as the features do. The term ''syndrome'' is most often used when the reason that the features occur together (pathophysiology) has not yet been discovered. A familiar syndrome name often continues to be used even after an underlying cause has been found. Many syndromes are named after the physicians credited with first reporting the association; these are "eponym" syndromes.
IMDb: China Syndrome, The - Provides information about the cast and crew from this 1979 film about a reporter discovering a hazard cover up at a nuclear power plant.
History: The China Syndrome - Features plot synopsis, cast, crew, and information concerning the real events behind the movie.
Rottentomatoes: The China Syndrome - Reviews from the critics and audiences, plot synopsis, cast, crew, tidbits, and rating information.
Critique of The China Syndrome - The Nuclear Energy Institute reviews the China Syndrome film based on facts and figures from a real incident at Three Mile Island.
Up Syndrome - Follows a year in the life of a man with Down syndrome. Synopsis, Rene Moreno's biography, credits, images, review excerpts, and links.
Herman Yau - Hong Kong director of The Untold Story, Ebola Syndrome, the Troublesome Night series, and From the Queen to the Chief Executive.
Sleeping Beauty Syndrome - Series of short films about suicide, by Andrew Barranca. Information, actors, video clips, and filmmaker biography.
Transparent Hair Syndrome - Fan art, image gallery, profile, downloads, and links.
Kurama's Territory - Shrine with character profile, images, poll, links, "Kurama Syndrome," fan works and other character highlights.
Afraid to Look Down - Actor/playwright Cullen Douglas' solo play about the journey he took in becoming a first-time father to his oldest son born with Down syndrome.