This is the cause for approximately ninety- five percent of the people affected by Down syndrome. The extra chromosome is usually found on the twenty-first pair. The next cause only affects 1 percent of the Downs population. It is known as mosaicism. This is caused from an error during cell division right after conception has occurred.
Down syndrome is a genetic disease where there is an extra chromosome on the 21st chromosome. Now there are three types of Down syndrome Trisomy 21, Mosaic Down syndrome, and Translocation Down syndrome. First we’ll talk about Trisomy 21. According to Mayo Clinic Staff (2011) “More than 90 percent of the time, Down syndrome is caused by trisomy 21. A child with trisomy 21 has three copies of chromosome 21 — instead of the usual two copies — in all of his or her cells.”(Para.3) so from this we can conclude that this is the most common type of Down syndrome.
Down syndrome is the most common birth defect in the United States and occurs in about 1 in every 800 infants. This birth defect does not have any treatments to cure the disease. This disease was discovered in 1866 and named after the physician who discovered it, John Langdon Down. There are three different types of Down syndrome, the most common being trisomy 21. Trisomy-21 is an extra copy of the 21st chromosome.
bizarre genetic disease that seems to accelerate ageing could hold the key to longer lives for children with progeria.Progeria is an extremely rare, fatal genetic condition which causes babies to age quickly. Progeria was first described in an academic journal by Dr. Jonathan Hutchinson in 1886 and also by Dr. Hasting Gilford in 1897 both man was from England (Nordqvist 1). After discovering the two people they later came up with a new name for Progeria called Hutchinson-Gilford Progeria Syndrome (HGPS). Today in life there 53 cases of Progeria around the world and only 2 in the UK.1 in every 4 to 8 million babies are born with Progeria. Progeria effect all race equal boys and girls.
Trisomy 21 is the most common type of down syndrome and it account for 95% of cases. When someone has trisomy 21 they have 47 chromosomes instead of 46 in every cell, which is caused by an error in cell division known as nondisjunction. Usually a baby inherits genetic information from both parents, 23 from each parent, but at some point during cell division a pair of 21st chromosomes in either the X or Y chromosome fails to separate, causing the child to have an extra 21st chromosome. This one extra chromosome is the cause of down syndrome’s development delays and physical features that are associated with down syndrome. Translocation down syndrome accounts for about 3% of cas... ... middle of paper ... ...hat conceive over the age of 35 and older are most likely to have a child with the condition.
Down Syndrome in Children Down syndrome is one of the most common and easily recognized genetic disorders. It is caused by abnormal cell division that involves the 21st chromosome pair of the 23 pairs of chromosome found in all normal human cells. There are three types of these abnormalities, which are non-disjunction, translocation, and mosaicism. Ninety five percent of children born with Down syndrome are a non-disjunction type which is three rather than two chromosome 21s. About three to four percent of cases are because of translocation which is chromosome 21 detaches and attaches to another chromosome.
However, females of a certain race, nationality or those who live in a certain region of the world have the same risk of having Turner’s. One in every 2000 to 2500 baby girls are born with Turner’s, according to the National Health Service in the United Kingdom. Normally if a baby is conceived with an X chromosome missing, the body will naturally abort the baby, which is a miscarriage. Turner’s is usually the cause of almost 10% of miscarriages in the first trimester. Monosomy is the reason that one X chromosome is missing completely, which means that every cell in the person’s body is missing one X chromosome.
There are three possible mutations to cause this inactivity. The most common cause is the deletion of the part of chromosome 15 that is inherited from the father, occurring in 70% of cases. In 25% of cases uniparental disomy (UPD) occurs and two copies of the chromosome are received from the father and none from the mother. 5% of patients diagnosed with Prader-Willi syndrome have an ‘imprinting mutation’. This is a form of translocation and means that the sequences of the genes on chromosome 15 are altered.
It is a pretty rare genetic disorder affecting only about 1 in every 5,000 people. This syndrome is from a mutation of a gene on chromosome 15 and this causes problems in the production of fibrillin-1 which is a protein that is an important part of connective tissue. The name for the gene is FBN1. Basically, it is the “glue” that helps to support the tissues in the human body. A child born to a parent with this syndrome has a 50% of having it.
Rarely is it inherited, Down syndrome is caused by three types of chromosomal abnormalities: Trisomy 21, Mosaic Down syndrome, and Translocation Down syndrome. The most common variation, Trisomy 21, occurs in about 95% of cases. According to “Down Syndrome”, this common variation is caused by “an error during the formation of the egg or sperm” and results in “either one having an extra chromosome.” After the sperm and egg mate, the cells produced will have three copies of chromosome 21. In addition, Mosaic Down syndrome, which accounts for 3% of cases, leads to some cells being affected with three copies of chromosome 21, with others unaffected. 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”).