Jan 27 2009
We will be soon going for a NT Scan – This is done to detect the Down’s Syndrome and here is some info on Down Syndrome
Note: All information on this blog is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
The Following are various facts and figures compiled from the internet, the credit should go the Original Contributors.
What is this Down’s Syndrome & Who discovered this?
Down syndrome, also known as trisomy 21 is a chromosomal disorder caused by the presence of all or part of an extra 21st chromosome. It is named after John Langdon Down, the British doctor who described the syndrome in 1866
Did not understand, can you explain in Layman’s terms?
Down syndrome is a genetic condition that causes delays in physical and intellectual development. It occurs in approximately one in every 800 live births. Individuals with Down syndrome have 47 chromosomes instead of the usual 46. It is the most frequently occurring chromosomal disorder.
Individuals with Down syndrome tend to have a lower than average cognitive ability, often ranging from mild to moderate developmental disabilities. A small number have severe to profound mental disability.
The incidence of Down syndrome is estimated at 1 per 800 to 1,000 births, although these statistics are heavily influenced by the age of the mother (1 in 1530 pregnancies at age 20, to 1 in 30 at age 44 )
Can you explain in One Sentence?
Down syndrome is a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically.
Whom Does it Affect?
Down syndrome is not related to race, nationality, religion or socioeconomic status. The most important fact to know about individuals with Down syndrome is that they are more like others than they are different.
But,, How & Why Does this Happen?
If a pair of number 21 chromosomes fails to separate during the formation of an egg (or sperm), this is referred to as nondisjunction. When that egg unites with a normal sperm to form an embryo, that embryo ends up with three copies of chromosome 21 instead of the normal two. The extra chromosome is then copied in every cell of the baby’s body.
Interestingly, nondisjunction events seem to occur more frequently in older women. This may explain why the risk of having a baby with Down syndrome is greater among mothers age 35 and older.
Cure for Down Syndrome?
No cure exists for Down syndrome. But physical therapy and/or speech therapy can help people with the disorder develop more normally. Screening for common medical problems associated with the disorder, followed by corrective surgery, can often improve quality of life.
Although no one knows for sure why DS occurs and there’s no way to prevent the chromosomal error that causes it, scientists do know that women age 35 and older have a significantly higher risk of having a child with the condition.
What are the Chaarecteristics of Down Syndrome?
Many of the common physical features of Down syndrome also appear in people with a standard set of chromosomes. They may include
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Distinct Facial Features- like a Flat Face, a Small Broad Nose, Abnormally Shaped Ears
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A Single Transverse Palmar Crease (a single instead of a double crease across one or both palms, also called the Simian crease),
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An almond shape to the eyes caused by an epicanthic fold of the eyelid,
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Upslanting Palpebral Fissures (the separation between the upper and lower eyelids),
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Shorter Limbs,
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Poor Muscle Tone,
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A larger than normal space between the big and second toes, and protruding tongue.
Health concerns for individuals with Down syndrome include a higher risk for congenital heart defects, gastroesophageal reflux disease, recurrent ear infections, obstructive sleep apnea, and thyroid dysfunctions.
How do you detect Downs Syndrome? – Lengthy but Detailed Answer
Two types of prenatal tests are used to detect Down syndrome in a fetus: Screening Tests and Diagnostic Tests. Screening tests estimate the risk that a fetus has DS; diagnostic tests can tell whether the fetus actually has the condition.
Screening tests are cost-effective and easy to perform. But because they can’t give a definitive answer as to whether a baby has DS, these tests are used to help parents decide whether to have more diagnostic tests.
Diagnostic tests are about 99% accurate in detecting Down syndrome and other chromosomal abnormalities. However, because they’re performed inside the uterus, they are associated with a risk of miscarriage and other complications.
For this reason, invasive diagnostic testing previously was generally recommended only for women age 35 or older, those with a family history of genetic defects, or those who’ve had an abnormal result on a screening test.
Screening tests include:
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Nuchal translucency testing. This test, performed between 11 and 14 weeks of pregnancy, uses ultrasound to measure the clear space in the folds of tissue behind a developing baby’s neck. (Babies with DS and other chromosomal abnormalities tend to accumulate fluid there, making the space appear larger.) This measurement, taken together with the mother’s age and the baby’s gestational age, can be used to calculate the odds that the baby has DS. Nuchal translucency testing is usually performed along with a maternal blood test.
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The triple screen or quadruple screen (also called the multiple marker test). These tests measure the quantities of normal substances in the mother’s blood. As the names imply, triple screen tests for three markers and quadruple screen includes one additional marker and is more accurate. These tests are typically offered between 15 and 18 weeks of pregnancy.
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Integrated screen. This uses results from first trimester screening tests (with or without nuchal translucency) and blood tests with second trimester quad screen to come up with the most accurate screening results.
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A genetic ultrasound. A detailed ultrasound is often performed at 18 to 20 weeks in conjunction with the blood tests, and it checks the fetus for some of the physical traits abnormalities associated with Down syndrome.
Diagnostic tests include:
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Chorionic villus sampling (CVS). CVS involves taking a tiny sample of the placenta, either through the cervix or through a needle inserted in the abdomen. The advantage of this test is that it can be performed during the first trimester, between 8 and 12 weeks. The disadvantage is that it carries a slightly greater risk of miscarriage as compared with amniocentesis and has other complications.
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Amniocentesis. This test, performed between 15 and 20 weeks of pregnancy, involves the removal of a small amount of amniotic fluid through a needle inserted in the abdomen. The cells can then be analyzed for the presence of chromosomal abnormalities. Amniocentesis carries a small risk of complications, such as preterm labor and miscarriage.
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Percutaneous umbilical blood sampling (PUBS). Usually performed after 20 weeks, this test uses a needle to retrieve a small sample of blood from the umbilical cord. It carries risks similar to those associated with amniocentesis.
After a baby is born, if the doctor suspects DS based on the infant’s physical characteristics, a karyotype — a blood or tissue sample stained to show chromosomes grouped by size, number, and shape — can be performed to verify the diagnosis.
How do you help such a child?
Individuals with Down syndrome benefit from loving homes, early intervention, inclusive education, appropriate medical care and positive public attitudes. Moreover, enriched environments significantly increase their capacity to learn and lead a meaningful life.
Down syndrome cannot be overcome, education and proper care will improve quality of life
Some Links & Resources on DS ?
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