Three Different Types Of Down Syndrome

Down syndrome is characterized as a chronic genetic chromosomal disorder which alters one’s cognitive growth, intellectual development, and physical characteristics. This extremely widespread condition is most prominently existent in human beings whose genetic makeup is composed of an additional copy of chromosome 21. Additionally, these human beings are known for acquiring 47 chromosomes rather than the conventional 46 chromosomes. This chromosomal abnormality is extremely common, yet highly spontaneous. To illustrate, the prevalence of Down Syndrome is exhibited as around

Down syndrome is a genetic disorder that affects a person’s facial features and intelligence. Down syndrome is also commonly known as Down’s syndrome, Trisomy 21, Trisomy G, 47,XX,+21, or 47,XY,+21. In 1866, English physician John Langdon Down is known as the “father” of Down syndrome. He was given that title for his publication of an accurate description of a person with Down syndrome, hence the reason why the disorder was named after him; although, this disorder was known as “Mongolism” until the 1970s. More information was learned about Down syndrome in 1959 when French physician Jérôme Lejeune identified that the disorder was caused by a chromosomal error. Then in 2000, a team of scientists was able to classify roughly 329 genes on chromosome 21, opening the door to many more advancements in the world of research for Down syndrome.

Down syndrome is a disability where a person has more than two of the chromosome 21 (Routh 6). There are three different types of Down syndrome, Standard Trisomy 21, Translocation, and Mosaic Down syndrome. Standard trisomy is the most most common type of Down syndrome, and it appears in ninety-five percent of all Down syndrome cases. Translocation is when a patient has an extra piece broken off the original chromosome 21. It sticks onto another chromosome. It sometimes can be inherited. The final type is Mosaic, it has an extra chromosome 21 in some cells, but not all. With Mosaic, the harshness of some effects depend on the number of cells that have an extra chromosome 21 and where they are located (14). Overall about 4,000 people are affected by Down syndrome. Boys are more likely to be affected than girls(18), and the older the mother is when pregnant, the higher the risk(44).

Down syndrome is also called 21 trisomy, which is obviously pointed out the disorder occurs at the chromosome 21. Genetically, it has been found that there are 22 pairs of autosomes and one pair of sex chromosomes, where X and Y are sex chromosomes representing female and male respectively. These two kinds of chromosome pairs are normally made up 46 chromosomes in total while children with Down syndrome have 47 chromosomes, meaning they have one extra chromosome on the chromosome 21. This chromosomal disorder happens occasionally and randomly. One cannot put blame or fault on the individual or parent when the gene is

Trisomy 21 is caused by an error in cell division which is called nondisjunction. Nondisjunction results when the embryo gets three copies of chromosome 21 instead of two. This usually occurs at or prior to conception, a pair of 21st chromosomes in either the sperm or the eggs fails to separate. Since this occurs so early on, the extra chromosome is then replicated in every cell of the body. This type of Down syndrome accounts for 95% of cases (“What”). Translocation accounts for about 4% of cases. In this types the total number of chromosomes in the cells remain 46, but an additional full or partial copy of chromosome 21 attaches to another chromosome (usually 14). The presence of the extra full or partial chromosome 21 causes the characteristics of Down syndrome (“What”). Mosaicism or mosaic Down syndrome is a mixture of the two other types. It is characterized by a mixture of two types of cells, some containing the usual 46 chromosomes and some containing 47. The cells that do contain 47 chromosomes contain an extra chromosome 21. This type accounts for only 1% of all the cases of Down syndrome. Some research has shown that individuals with mosaic Down syndrome may have fewer characteristics of Down syndrome that those with other types

Down syndrome, also known as Trisomy 21, is a genetic disorder. It is caused by an abnormality in the number of chromosomes. DNA (deoxyribose nucleic acid) chromosomes are originate in the cell and are comprised of genes, which decide hereditary traits (Epstein pg.199). If a person has an extra chromosome on chromosome number 21 out of 23 they will have Down syndrome. The extra chromosome may delay the growth of a child’s physical and mental development which may lead to mental retardation. Normally, a person has 46 chromosomes, and will receive 23 pairs of chromosomes from the mother and 23 from the father totaling 46. But someone with Down syndrome will have 47. Although many theories have been developed, it is not known what actually

It’s symtoms include physical growth impedement, facial and body abnormality, and intellectual blockage. Down syndrome would be considered a common disorder in humans. It is estimated to have 1000 babies born each year with down syndrome due to genetic errors. Down Syndrome was first described by British doctor John Langdon Down in 1866; and the cause was discovered by French researcher Jean Esquirol in 1959, which was the extra chromosome 21.

Down syndrome is a disorder in which an individual gets a full or partial extra copy of chromosome 21. Normally, at the time of conception a baby inherits genetic information from its parents in the form of 46 chromosomes: 23 from the mother and 23 from the father, but in most cases of Down syndrome a child gets an extra chromosome 21 for a total of 47 chromosomes instead of 46. The three types of Down syndrome are trisomy 21 (nondisjunction), translocation and mosaicism. According to the National Down Syndrome Society (2012), “One in every 691 babies in the United States is born with down syndrome, making down syndrome the most common genetic condition. Approximately 400,000 Americans have Down syndrome and about 6,000 babies with Down syndrome are born in the United States each year.” Down syndrome causes intellectual disability, developmental delays, and a distinct facial appearance such as a small head, a flattened face especially the bridge of the nose, an almond-shaped eyes that slant up, a short neck, small ears, a tongue that tends to stick out of the mouth, tiny white spots on the iris of the eye, small hands and feet, a single line across the palm of the hand (palmar crease), poor muscle tone or loose joints, and shorter in height as children and adults.

Down Syndrome, also known a Trisomy 21, is the most common cause of Mental deficiency that occurs from childbirth. Down syndrome is a genetic disorder that occurs when there is an extra chromosome Present. The presence of an extra chromosome causes this genetic disorder because chromosomes contain all of our genetic information and when this information is disrupted during cell division for example, when one is conceived with an added chromosome this causes many problems with the coding of the DNA. down syndrome occurs during cell division in early fetal stages. usually one inherits 23 chromosomes from each parent but in some cases people inherit an extra chromosome and receive three sets of chromosome 21, this is when the genetic disorder

Following several technical and medical advances and breakthroughs in the twentieth century, in 1959 French physician Jerome Lejeune identified Down Syndrome as a chromosomal abnormality. It was noted that there was 47 chromosomes in the cell of an afflicted person versus the normal 46. It was later determined that there was a third chromosome 21, called trisomy-21 (figure 1). Down Syndrome occurs in about 1 in every 800 to 1000 births and has affected more than 350,000 lives in the US alone It is caused by the extra chromosome 21 when an embryo has three copies of chromosome 21. Ninety-five percent of the time this is caused by disjunction during cell division. Due to younger women’s higher fertility rate, 80% of Down Syndrome babies are born to women under age 35. However, the chances of having a Down Syndrome baby increases with age of the parents.2 The phenotypes, or symptoms, of a Down Syndrome face are as follows: low muscle tone (weak muscle structure), small nose, flat face, slanted eyes (upward) and abnormally shaped ears (figure 2)

Down Syndrome is a developmental disorder caused by an error in the process of cell division. This disorder is characterized by an extra copy of chromosome 21 (trisomy)(Segal & Pesco, 2015). It is the most common chromosomal disorder and affects 1 in 700 live births (Ramia, Musharrafieh, Khaddage, & Sabri, 2014). According to Segal and Pesco (2015), Down Syndrome is characterised by physical features such as distinct facial characteristics, low muscle tone; conditions such as congenital heart disease; and Intellectual Disability with IQs typically ranging from 30 to 70.

Trisomy 21(Down Syndrome) is one of the most common types of chromosomal mutation. First published by John Langdon Down in 1866 and associated with chromosomes in 1959 by Jerome Lejeune, this mutation has affected thousands of infants around the world. The main cause for Down Syndrome is the formation of a 2 chromosome coming together in addition to another that does not belong. This produces extra genetic material. This occurs in the 21st chromosome of a human karyotype and this causes the newborn to have 47 chromosomes instead of the normal 46 chromosomes. So when the egg and the sperm come together there is an uneven amount of chromosomes coming from each parent.

Down syndrome is caused by an abnormality with the 21st chromosome. It was first observed by John Langdon Down in 1866. It was not until 1959 that it would be classified as a chromosomal disease by french physician Jérôme Lejeune. According to the article, “Down syndrome occurs when an individual has a full or partial extra copy of

What is down syndrome? Down syndrome is a diseases that is a natural born diseases. Down syndrome is a chronilogical disease. It affects 1 in 800 lives born out of 1 in 1000. What are down syndrome symptoms? Symptoms of down syndrome are mental retardation sometimes have difficulties learning and usually a very characteristic facial. Down syndrome is one of the hardest deasese to diagnos. They do a genetic blood and skin test to afferm the down syndrome deases. Trismoy 21 means that every cell in the body has 3 copies of chromosomes inside the trismoy. When there is ussually only two copies of chromosomes down syndrome people have 21 copies. Having any extra amount of chromosomes it will cause growth defections. With 21 chromosomes in the

Down syndrome is a genetic disorder in which a person is born with an extra copy of chromosome 21. There are three genetic variations that cause Down syndrome: Trisomy 21, Mosaic Trisomy 21 or Translocation Trisomy 21. There are many ways in which theses disorders affect the body.  Trisomy 21 occurs when an egg or sperm comes in with an extra copy of chromosome 21, then, once an embryo is formed and starts to develop, the chromosome is replicated in every single cell of the embryo. Trisomy 21 is the most common type of Down syndrome. About 92% of Down syndrome patients have this type. People with Trisomy usually have physical problems.