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.
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.
It is where the body has 47 Chromosomes instead of 46 (Crosta). Trisomy 21 is caused by a problem in the cell division called non-disjunction; it leaves a sperm or an egg cell with an extra copy of chromosome 21. 95% of Down syndro... ... middle of paper ... ...hromosome. Most pregnancies for a mothers 40 years of age or older will have a higher risk of having a Down syndrome child. The older the mother is, the more of a chance she will have for her baby to be diagnosed with Down syndrome.
The issue of infant mortality affects the United States because we have babies that die before their first birthday. Another reason that infant mortality affects the United States is we have resources that could help other countries with a higher infant mortality rate. With 7.046 billion people (as of 2012) and growing you would expect the people in the world to affect infant mortality, but they don’t. There are many causes of infant mortality, people not being one of them though. There are ten other problems that cause infant mortality with many more that have not been discovered yet or that do not play as big of factor in infant mortality.
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.
One to two percent of persons born with this disorder have uncorrectable heart defects at birth. The average life expectancy for all others is now beyond age 55 years. *Today less than 5% of persons with Down syndrome have severe-to- profound mental retardation. The majority are on the border of mild-to-moderate mental retardation, and some are exhibiting normal IQ scores today. *The average reading level for persons with Down syndrome is 3rd grade, with many reading at 6th-12th grade levels today.
This is the additional genetic material alters of the course of development and causes the characteristics that are associated with Down syndrome. A few of common physical traits of the Down syndrome disorders are low muscle tone, small stature, an upward slant to the eyes, and a single deep crease across the center of the palm of your hand. Although each person that is diagnose with Down syndrome may have possess these characteristics to the different degrees. One in every 691 babies in the United States is born with Down syndrome. Which is marking Down syndrome the most common genetic condition of most disorder.
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.
About three to four percent of cases are because of translocation which is chromosome 21 detaches and attaches to another chromosome. Mosaicism accounts for only one to two percent of births, which is an abnormal cell division with the normal 46 chromosomes while the others have 47 creating a mosaic of normal and abnormal cells (Encarta.p1). The presence of Down syndrome in children is also due to the age of the mother. A twenty five year old woman' s chance of having a baby with Down syndrome is 1 in 1,250, but a woman who is thirty five it's 1 in 378 and a woman 45 it's1 in 30 (Encarta.p2). Diana Danilenko-Dixon, M.D.
In this form some cells have an extra chromosome 21 while some cells have the regular two. Sometimes problems occur before fertilization, as in the case of trisomy 21 and translocation, when an egg or sperm cell divides incorrectly leaving it with an extra copy of chromosome 21 or apiece of chromosome 21 breaks off and attaches to another chromosome. Unlike trisomy 21 and translocation down syndrome, mosaic down syndrome occurs after fertilization. The likelihood of having a child with Down syndrome increases as the mother gets older. According to the American Pregnancy Association the risk at the mothers age of 20 is 1:1600, 25 is 1:1300, 30 is 1:1000, 35 is 1:365, 40 is 1:90 and 45 is 1:30 (APA).