Down Syndrome (DS) is the most common birth defect and congenital disorder in the United States caused by the presence of an extra 21st chromosome. This genetic condition causes delays in the way a child develops, both mentally and physically. People with Down Syndrome have distinctive features, such as, mild to moderate mental retardation, weak muscle tone, small head and ears, upward slant to the eyes, hyper flexibility, short stature, protruding tongue, and a flattened facial profile. The severity of these problems varies greatly among affected individuals.
There are three types of Down Syndrome: trisomy 21 (nondisjunction), translocation, and mosaicism. People often can’t tell the difference between each type without looking at the chromosomes because the physical and behavior features have many similarities. Each type of Down Syndrome is based on a percentage regarding documented cases of Down Syndrome in the United States. The most common type of Down Syndrome is Trisomy 21 (nondisjunction). Down Syndrome is normally caused by an error in cell division called “nondisjunction.” Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two. Before
…show more content…
“If you had a roomful of 100 babies with Down Syndrome, they would all look alike and have similar features and health problems. You would not be able to pick out the babies that have translocation.” Mosaicism, the 3rd and rarest type of Down Syndrome is caused by abnormal cell division after fertilization. Mosaicism is used to describe the presence of more than one type of cell in a person. Clinically, babies born with mosaic Down Syndrome can have the same features and health problems seen in babies born with trisomy 21 or translocation Down Syndrome. However, the presence of cells with the normal number of chromosomes (46) may result in a less severe presentation or fewer characteristics of Down
Down’s syndrome is a chromosomal condition that is caused by an extra 21st chromosome as there is an error in the body’s cell division. Every human has a nucleus in every cell in the body which contains genes that are grouped along with chromosomes. The normal number of
Down syndrome is a disorder that comes with some defects, such as in the face, heart, sight, and hearing, and other health related problems. It also is the most common genetic defect, affecting many babies. Down syndrome is caused when the chromosomes are being divided during meiosis the cell keeps both copies of chromosome #21, which means the person with Down syndrome has an extra copy in every cell in their body. This is a sad genetic disorder that can change a person's life. Even though it is a devastating gene mutation, the people with Down syndrome are some of the most loving of all people.
“About 13 of every 10,000 babies born in the United States each year is born with Down syndrome. It affects an equal number of male and female babies” (Johnson P. A. 2014). Down syndrome is a genetic disorder that found across the world, however it is more prevalent in the United States. The cause of the disorder roots to the paring of the human chromosomes. A normal human receives 23 pairs of chromosomes, each pair coming from mother and father. In Down syndrome most people affected have an abnormal cell division of the chromosome. Both parents are carriers of the There are three types of variations that includes trisomy 21, mosaic, and translocation.
Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells. An error in cell division called nondisjunction results in a reproductive cell 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.
Down Syndrome is a condition that cannot be physically passed on from one person to the next. It is a genetic disorder that is inherited through our parents when something goes wrong during pregnancy. As a result, they have a combination of features typical of Down Syndrome, including some degree of cognitive disability, as well as other developmental delays. One thing we should always keep in mind is that they are children and having Down Syndrome comes second.
Down syndrome was discovered in the 1800’s by a man named John Langton Down. Down syndrome1 is a condition that occurs in the chromosomes. The syndrome affects the intellectual ability of the person effected, their facial appearance and causes hypotonia2. Children born with this usually experience different types of birth defects. These birth defects can include heart defects and intestine blockage. People with Down syndrome are also at a high risk of developing other medical conditions. Some medical conditions include gastro esophageal reflux3, celiac disease4, hypothyroidism5, and leukemia6. Also some visual and hearing problems can arise. There are three types of Down syndrome.
Trisomy 21 is a chromosomal disorder. “It is caused by an extra chromosome 21.” (http://www.geneticcounselling.eu) This is due to nondisjunction. During meiosis a complication occurs which results in an extra chromosome. An offspring does not inherit Trisomy 21 (Down Syndrome), but other forms of the disorder can be passed along from a parent to a child.
Down syndrome is caused by a problem with a baby’s chromosome. Chromosomes are cell structures made up genetic DNA (“Chromosomes”). Most people with Down syndrome have 47 chromosomes. This changes the way the brain
Down syndrome, a genetic disorder, is the most common cause for intellectual disabilities, occurring at an average of one out of every 700 births (CDS, 2006). This disorder is caused by the extra chromosome 21 (also known as Trisomy 21). According to Hassold and Sherman (2002), the probability of giving birth to a child with DS is not linked to any race, ethnicity, socioeconomic status or geographic location. Maternal age seems to be the only etiological factor that may cause DS.
Trisomy 21 or more commonly known as down syndrome is a condition in which an individual has a full or partial extra copy of chromosome 21 (What is Down Syndrome?, 2012). It was first described as a disorder in 1866 by doctor John Langdon Down and it is the most common cause of cognitive impairment (Heyn, 2014). Today there are three known types of down syndrome trisomy 21 or called nondisjunction, translocation, and mosaicism. Regardless of the type of down syndrome a child may have, they all have an extra portion of chromosome 21 present and the cause is still unknown today (What is Down Syndrome?, 2012). With the cause unknown many people have misconceptions or don’t understand what down syndrome is. That is why I chose to research down
Down syndrome can be caused by a random error in cell division which results in a presence of an extra copy of chromosome 21. This type of error is called nondisjunction. Usually when one cell divides in two, pairs of chromosomes are split so that one of the pair goes to one cell, and the other from the pair goes to the other cell. In nondisjunction something happens that makes both chromosomes from one pair go into one cell and no chromosome from that pair goes into the other cell. A lot of the time, the error occurs at random during the formation of an egg or sperm. After a lot of research is has been discovered that in more than 90% of cases, the extra copy of chromosome 21 comes from the mother in the
The cause of this disorder is because of an extra chromosome in the body. About 90% of Down Syndrome cases are caused by this extra chromosome, chromosome 21 (this is why it is also called Trisomy 21). An extra chromosome originates in either the sperm or the egg. When the egg and the sperm unite to form the fertilized egg, two instead of three chromosomes in chromosome 21 are present. As the cells divide the extra chromosome is repeated in every cell.
Down syndrome is a common birth defect that is genetic. It is a chromosomal disorder caused by an error in cell division that results in an extra 21st chromosome. Most children born with Down syndrome have some level of mental retardation.
Down Syndrome or Trisomy 21 is an extra copy of chromosomes 21; healthy babies have two copies, while down syndrome babies have three copies. Blood tests that pregnant women get have sparked a debate about aborting unborn babies with down syndrome because the parents “can’t handle it” or “dont know how to care for a baby with a disability.”
‘’Down syndrome is a type of mental retardation caused by extra genetic material in chromosome 21’’(1). In the beginning, children with Down syndrome were referred as “mongoloids” because they looked like people from Mongolia but, the term was changed to Down’s syndrome. Down’s Syndrome named after John Langdon Down, the man who first described it (2). Down syndrome due to a genetic cause and it has more than one type and characteristics.