Down syndrome is a condition in which extra genetic material causes delays in the way a child develops, both physically and mentally. Down syndrome (sometimes called Down's syndrome) is a condition in which a child is born with an extra copy of their 21st chromosome — hence its other name, trisomy This causes physical and mental developmental delays and disabilities.‎Causes · ‎Types · ‎Risk factors · ‎Symptoms. Down syndrome is a genetic disorder caused when abnormal cell division results in an extra full or partial copy of chromosome This extra.


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British physician John Langdon Down first described the physical features of Down syndrome inand thus the disorder was later named for him. Karyotype down syndrome definition morphology showing a female with Down syndrome.

What to know about Down syndrome

The physical and cognitive impacts of Down syndrome range from mild to severe. Some common physical signs of the disorder include a small head, flattened face, short neck, up-slanted eyes, low-set down syndrome definition, enlarged tongue and lipsand sloping underchin. Other characteristics of the disorder may include poor muscle tone, heart or kidney malformations or bothand abnormal dermal ridge patterns on the palms of the hands and soles of the feet.

Down syndrome definition disability occurs in all persons with Down syndrome and usually ranges from mild to moderate.

Down Syndrome

Congenital heart disease is down syndrome definition in about 40 to 60 percent of people with Down syndrome. 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.

However, the American College of Obstetrics and Gynecology ACOG now recommends that all pregnant women be offered screening with the option for down syndrome definition diagnostic down syndrome definition for Down syndrome, regardless of down syndrome definition.

If you're unsure about which test, if any, is right for you, your doctor or a genetic counselor can help you sort through the pros and cons of each. 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.

Down syndrome: Causes, symptoms, and diagnosis

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 down syndrome definition along with a maternal blood test.

The triple screen down syndrome definition quadruple screen also called the multiple marker test.


These tests down syndrome definition the quantities of normal substances in the mother's blood. These tests are typically offered between 15 and 18 weeks of pregnancy. This uses results from first-trimester screening tests with or without nuchal translucency and blood tests with a second trimester quadruple screen to come up with the most accurate screening results.

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. It can be done in the 1st trimester and is more accurate at detecting Trisomy 21 than down syndrome definition blood tests.

Currently cell free DNA testing is only offered to women at high risk of having a baby with Down Syndrome.

Down syndrome

At 15 to 20 weeks, a small amount of amniotic fluid is obtained for analysis, using a needle inserted into the abdomen. Percutaneous umbilical blood down syndrome definition After 20 weeks, a small sample of blood is taken from the umbilical cord for analysis, using a needle inserted into the abdomen.

Down syndrome can also be diagnosed after a baby is born by inspecting the infant's physical characteristics as well as blood and tissue. Down syndrome definition There is no specific treatment for Down syndrome. People with the syndrome will receive care for health problems, just as other people down syndrome definition.

However, additional health screening for common problems may be recommended. Early intervention can help the individual maximize their potential and prepare them to take an active role in the community.

Down Syndrome | Definition of Down Syndrome by Merriam-Webster

There are three types of Down syndrome: This is the most common form of Down syndrome. Mosaicism Mosaicism down syndrome definition when a child is born with an extra chromosome in some but not all of their cells.

  • Down syndrome - Symptoms and causes - Mayo Clinic
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People with mosaic Down syndrome tend to have fewer symptoms than those with trisomy