The type of mutation that occurs in Down syndrome is aneuploidy that is the irregular number of chromosomes in a cell. The most common of the three is the trisomy 21 that occurs in about 90% of people with the disorder. In this factor the human is given three copies of the chromosome 21 instead of the common two copies. This occurs due to the complications of the cell division in the process of the egg or sperm. The next case is mosaic which happen when there are inequality of cells with three copies of chromosome 21 and others with the original two copies.
Down Syndrome is also (or formally) known as mongolism, and is the most frequent chromosomal abnormality in the United States. Over 350,000 people carry this condition. It is caused by an extra 21st chromosome. This is also known as trisomy 21. Instead of 46 chromosomes in each cell it was determined that an extra 21st chromosome affected Down syndrome, this occurs 95% of the time.
The idea of uterine exhaustion was based on the observation that many children with Downs Syndrome (DS) tended to be the last born members of large families. This was later accounted for as mere coincidence. The first formal reference to the anomaly came in 1866 in England by a physician at the Earlewood Asylum noting the distinct physical characteristics of this group of individuals. In the 1930’s, Adrian Bleyer hypothesized that the condition was caused by a failure of the chromosomes to separate but could provide no proof for this since an accurate human chromosome count had not yet been obtained by anyone. The correct number of 46 chromosomes was obtained in Sw... ... middle of paper ... ...rebrain Cholinergic and Pontine Catecholaminergic Nuclei in the Brain of Trisomy 16 Mouse, an Animal Model of Down’s Syndrome.
A genetic disorder is a sickness caused by one or many abnormalities or absentees in the genes or chromosomes. One interesting genetic disorder such as cancer, are found genetic but, can also be caused and affected by many by environmental factors such as being exposed to asbestos which may increase the risk of lung cancer and many other cancers. While on the other hand most disorders like Williams Syndrome are genetic and are primarily rare and only affect a limited amount of people about one in every several thousand. Because it is a genetic disorder that is estimated between 1 in 10,000 people worldwide, primarily caused by a micro-deletion on the seventh chromosome is what indicates the disorder being Williams Syndrome. Because Williams Syndrome is very uncommon within a large crowd among people, the causes that are known to trigger the disorder are very few.
Children that acquire Down syndrome have a genetic mutation in the gene called GATA1. Trisomy 21 is the most observed abnormality seen at birth and occurs in about 1 to 700 individuals. Children that are born with Down syndrome have an increased risk of acute megakaryoblastic leukemia (AML) and also acute lymphoblastic leukemia (ALL). In studies it shows that approximately 4-5% of children that are born with Down syndrome are also born with transient myeloprolifative disorder (TMD), a clonal preleukemia characterized by an accumulation of immature megakaryoblasts in the fetal liver and peripheral blood (Mailnge 2012). Acute Myeloid Leukemia develops when acquired changes in DNA of a developing marrow cell that which can turn into a leukemia cell that turns into a billion more cancerous cells.
According to the National Down Syndrome Society (NDSS), “one in every 691 babies born in the United States is born with down syndrome, making it the most common genetic disorder.” A person with this genetic defect tend to have delays in regards to physical growth, have a particular set of physical structures—particularly facial ones—, and have a moderate to severe intellectual impairment. There are several physical structures that are typical of someone with down syndrome. As said on the wikipedia page concerning down syndrome, they are namely: “abnormally small chin, oblique eye fissures on the inner corner of the...
Finally, Translocation Down syndrome results when an “extra part or a whole extra chromosome 21 is present, but it is attached or “trans-located” to a different chromosome rather than being a separate chromosome 21” (“Facts about Down Syndrome”). In this case, only an “unbalanced” translocation, where genetic material is either lost or gained can cause Down syndrome. Down syndrome remains the most prevalent genetic disorder in humans. According to the National Down Syndrome Society, it affects about 1 out of every 691 newborns and more than 400,000 individual... ... middle of paper ... ... at an increased risk for heart defects, vision and hearing problems, blood disorders, and digestive problems. Almost 50% of babies with the disorder have congenital heart disease.
It’s the most common genetic disorder in the world and affects 1 in every 691 babies born in the United States. Down syndrome is named after a British doctor, Langdon Down, who first described the condition in 1887. Langdon did not have down syndrome but wrote a paper entitled “Observations on the Ethnic Classifications of Idiots.” In his paper Langdon referred to down syndrome as the “Mongolian type of Idiot,” which resulted in people with down syndrome being called “Monogoloids.” It wasn’t until more than 60 years later, in 1959, that an extra 21 chromosome was identified as the cause by Dr. Jerome Lejune. There are three types of down syndrome trisomy 21, translocation, and mosaic down syndrome or mosaicism. Trisomy 21 is the most common type of down syndrome and it account for 95% of cases.
Neurofibromin acts like a tumor suppressor protein, so a person with NF1 is more prone to getting tumors, so without neurofibromin the mitosis cycle conti... ... middle of paper ... ...ere are three types of Neurofibromatosis, which are Schwannomatosis, which is the most severe, NF2, and finally the NF1, which is the most common. NF1 occurs one in every 3,000-4,000 births worldwide. Unfortunately, there still is no cure even though NF1 is the most common genetic disease in the world. Each person with NF1 has a unique case that can vary in the severity of their complications, one person my not be affected by it that much, while another is greatly impacted by it, and potential could need a lot of time consuming treatments. References Children’s Tumor Foundation (2014).