Drawings of Babies Medium Size Round Slanted Upwards Eyes on a Baby
What is Down's syndrome?
In every cell in the homo body there is a nucleus, where genetic material is stored in genes. Genes carry the codes responsible for all of our inherited traits and are grouped forth rod-like structures called chromosomes. Typically, the nucleus of each jail cell contains 23 pairs of chromosomes, half of which are inherited from each parent. Down syndrome occurs when an individual has a total or fractional extra copy of chromosome 21.
This additional genetic cloth alters the class of development and causes the characteristics associated with Downwardly syndrome. A few of the common physical traits of Down syndrome are low muscle tone, small stature, an upward slant to the eyes, and a single deep crease across the heart of the palm – although each person with Downwards syndrome is a unique private and may possess these characteristics to different degrees, or not at all.
How Common is Down syndrome?
Co-ordinate to the Centers for Disease Control and Prevention, approximately ane in every 700 babies in the United States is born with Down's syndrome, making Downwardly syndrome the almost mutual chromosomal condition. About 6,000 babies with Downwards syndrome are born in the U.s. each year.
When Was Down Syndrome Discovered?
For centuries, people with Down's syndrome accept been alluded to in art, literature and science. It wasn't until the late nineteenth century, notwithstanding, that John Langdon Down, an English physician, published an accurate clarification of a person with Down syndrome. It was this scholarly work, published in 1866, that earned Down the recognition as the "father" of the syndrome. Although other people had previously recognized the characteristics of the syndrome, it was Downwards who described the condition as a distinct and split up entity.
In recent history, advances in medicine and science take enabled researchers to investigate the characteristics of people with Downward syndrome. In 1959, the French doc Jérôme Lejeune identified Downwardly syndrome every bit a chromosomal status. Instead of the usual 46 chromosomes nowadays in each prison cell, Lejeune observed 47 in the cells of individuals with Downward syndrome. It was later determined that an extra partial or whole copy of chromosome 21 results in the characteristics associated with Down syndrome. In the year 2000, an international team of scientists successfully identified and catalogued each of the approximately 329 genes on chromosome 21. This accomplishment opened the door to dandy advances in Down syndrome research.
Are There Different Types of Down syndrome?
TRISOMY 21 (NONDISJUNCTION)
Down's syndrome is usually caused past an error in prison cell division called "nondisjunction." Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual 2. Prior to or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to split. As the embryo develops, the actress chromosome is replicated in every cell of the body. This blazon of Down syndrome, which accounts for 95% of cases, is called trisomy 21.
MOSAICISM
Mosaicism (or mosaic Down syndrome) is diagnosed when there is a mixture of two types of cells, some containing the usual 46 chromosomes and some containing 47. Those cells with 47 chromosomes comprise an extra chromosome 21.
Mosaicism is the least common form of Down syndrome and accounts for only about 1% of all cases of Down's syndrome. Research has indicated that individuals with mosaic Down syndrome may have fewer characteristics of Down syndrome than those with other types of Downwards syndrome. However, broad generalizations are not possible due to the broad range of abilities people with Down syndrome possess.
TRANSLOCATION
In translocation, which accounts for nigh iv% of cases of Down syndrome, the full number of chromosomes in the cells remains 46; however, an additional total or partial copy of chromosome 21 attaches to another chromosome, usually chromosome 14. The presence of the extra full or partial chromosome 21 causes the characteristics of Downwardly syndrome.
What Causes Down syndrome?
Regardless of the type of Down syndrome a person may have, all people with Downwardly syndrome accept an extra, critical portion of chromosome 21 nowadays in all or some of their cells. This boosted genetic material alters the course of development and causes the characteristics associated with Down's syndrome.
The crusade of the actress full or partial chromosome is yet unknown. Maternal age is the only factor that has been linked to an increased take a chance of having a baby with Down's syndrome resulting from nondisjunction or mosaicism. However, due to higher birth rates in younger women, 80% of children with Down syndrome are born to women nether 35 years of historic period.
There is no definitive scientific research that indicates that Down syndrome is caused by ecology factors or the parents' activities before or during pregnancy.
The boosted partial or full copy of the 21st chromosome which causes Downwardly syndrome can originate from either the begetter or the mother. Approximately 5% of the cases have been traced to the father.
Does Down Syndrome Run in Families?
All iii types of Down syndrome are genetic conditions (relating to the genes), just only i% of all cases of Downward syndrome have a hereditary component (passed from parent to child through the genes). Heredity is not a factor in trisomy 21 (nondisjunction) and mosaicism. However, in i-3rd of cases of Down's syndrome resulting from translocation there is a hereditary component – bookkeeping for virtually 1% of all cases of Down's syndrome.
The historic period of the mother does not seem to be linked to the run a risk of translocation. Most cases are sporadic – chance – events. However, in virtually one-third of cases, ane parent is a carrier of a translocated chromosome.
What Is the Likelihood of Having a 2d Child with Down's syndrome?
Once a woman has given birth to a baby with trisomy 21 (nondisjunction) or translocation, information technology is estimated that her chances of having another infant with trisomy 21 is 1 in 100 up until age 40.
The hazard of recurrence of translocation is well-nigh 3% if the begetter is the carrier and 10-fifteen% if the female parent is the carrier. Genetic counseling can determine the origin of translocation.
How Is Down's syndrome Diagnosed?
PRENATALLY
There are two categories of tests for Down syndrome that can exist performed before a baby is born: screening tests and diagnostic tests. Prenatal screens gauge the chance of the fetus having Down syndrome. These tests do not tell you for sure whether your fetus has Down syndrome; they only provide a probability. Diagnostic tests, on the other mitt, can provide a definitive diagnosis with about 100% accuracy.
There is an extensive menu of prenatal screening tests now bachelor for pregnant women. Virtually screening tests involve a blood test and an ultrasound (sonogram). The blood tests (or serum screening tests) measure quantities of various substances in the blood of the mother. Together with a woman'southward age, these are used to estimate her chance of having a child with Down syndrome. These blood tests are often performed in conjunction with a detailed sonogram to bank check for "markers" (characteristics that some researchers feel may have a significant association with Down syndrome). New avant-garde prenatal screens are at present able to find chromosomal material from the fetus that is circulating in the maternal claret. These tests are not invasive (similar the diagnostic tests below), simply they provide a high accuracy rate. Even so, all of these screens volition not definitively diagnose Down syndrome. Prenatal screening and diagnostic tests are at present routinely offered to women of all ages.
The diagnostic procedures available for prenatal diagnosis of Down's syndrome are chorionic villus sampling (CVS) and amniocentesis. These procedures, which bear upwards to a 1% run a risk of causing a spontaneous termination (miscarriage), are nearly 100% accurate in diagnosing Down syndrome. Amniocentesis is ordinarily performed in the second trimester between 15 and 20 weeks of gestation, CVS in the get-go trimester between 9 and xiv weeks.
AT BIRTH
Down's syndrome is usually identified at birth past the presence of certain physical traits: low musculus tone, a unmarried deep crease across the palm of the hand, a slightly flattened facial profile and an up slant to the eyes. Because these features may be present in babies without Downwards syndrome, a chromosomal assay chosen a karyotype is done to confirm the diagnosis. To obtain a karyotype, doctors depict a blood sample to examine the babe's cells. They photograph the chromosomes and and then group them by size, number, and shape. By examining the karyotype, doctors tin can diagnose Down syndrome. Another genetic examination called FISH tin can use like principles and confirm a diagnosis in a shorter amount of time.
Preferred Language Guide
Use this linguistic communication when referring to Down's syndrome and people who take Downwardly syndrome:
- People with Down's syndrome should ever be referred to as people starting time.
- Instead of "a Down syndrome child," information technology should exist "a kid with Down's syndrome." Besides avoid "Down'southward kid" and describing the condition as "Down'due south," equally in, "He has Down's."
- Down syndrome is a status or a syndrome, not a disease.
- People "have" Down syndrome, they do not "suffer from" it and are non "afflicted by" it.
- "Typically developing" or "typical" is preferred over "normal."
- "Intellectual disability" or "cerebral disability" has replaced "mental retardation" as the appropriate term.
- NDSS strongly condemns the apply of the give-and-take "retarded" in any derogatory context. Using this word is hurtful and suggests that people with disabilities are non competent.
Down vs. Down's
- NDSS uses the preferred spelling, Down syndrome, rather than Down's syndrome.
- Down syndrome is named for the English language physician John Langdon Down, who characterized the condition, merely did non have it. An "apostrophe south" connotes ownership or possession.
- While Down syndrome is listed in many dictionaries with both popular spellings (with or without an apostrophe s), the preferred usage in the United States is Down syndrome. The AP Stylebook recommends using "Down syndrome," also.
These downloadable versions of the Preferred Language Guide are available to impress and distribute:
- NDSS Preferred Language Guide
- NDSS Fact Sheet and Language Guide
Resource
EXTERNAL Resources
- Brighter Tomorrows
www.brightertomorrows.org
Brighter Tomorrows is a web-based resources for parents who have received a diagnosis of Down syndrome either prenatally or at birth. The site provides answers to common questions, educates nigh Down Syndrome and shares the stories of other parents with similar situations. - Down Syndrome Pregnancy
www.downsyndromepregnancy.org
This site provides information and support to expectant parents preparing for the nascency of a infant with Down syndrome.
- International Mosaic Down syndrome Association
www.imdsa.org
Offers back up and resource to families of and individuals with mosaic Downwardly syndrome through the lifespan
- Medline Plus: Health Topics – Down Syndrome
www.nlm.nih.gov/medlineplus/downsyndrome.html
An overview and list of resource on Down's syndrome and prenatal testing from Medline Plus, a service of the US National Library of Medicine and the National Institutes of Health
- National Society of Genetic Counselors
www.nsgc.org
Notice members of NSGC through the Find A Genetic Advisor search function
- Understanding a Down Syndrome Diagnosis
www.lettercase.org
Understanding a Down Syndrome Diagnosis is an accurate, counterbalanced and up-to-engagement booklet for utilise when delivering a diagnosis of Down syndrome. Information technology is bachelor every bit a costless due east-book from Lettercase.
DVDS
- Down Syndrome: The First 18 Months. Huckleberry Shoes Productions.
BOOKS
- A Parent's Guide to Down's syndrome: Toward A Brighter Hereafter. Pueschel, S. (2000). Baltimore, MD: Brookes Publishing.
- Babies with Down Syndrome: A New Parents' Guide (Third Edition). Skallerup, Due south. (Ed.) Bethesda, Doc: Woodbine Firm. (2008)
- Downs: The History of a Disability. Wright, D. New York, NY: Oxford Academy Printing. (2011)
- Tales of Normansfield: The Langdon Downward Legacy. Merriman, A. Beccles, UK: The Down's syndrome Clan. (2007)
- The Guide to Proficient Health for Teens and Adults with Downwardly Syndrome. McGuire, D. and Chicoine, B. Bethesda, MD: Woodbine House. (2010)
Source: https://www.ndss.org/about-down-syndrome/down-syndrome/
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