Down Syndrome – Trisomy 21

Down Syndrome is also referred to as Trisomy 21. 20 October is National Down Syndrome Day. The intend of this day is to create awareness about Down Syndrome and to communicate facts about the condition.

What is Down Syndrome?

Down Syndrome is a chromosomal disorder happening at conception.  Chromosomes are small “packages” of genes in the body.  They determine how a baby’s body forms and functions as it grows during pregnancy and after birth.  Babies with Down Syndrome have an extra number 21 chromosome (Trisomy 21) that causes delays in physical and intellectual development.  A medical term for having an extra copy of a chromosome is ‘trisomy.’

10 Quick facts about Down Syndrome

  1. Down Syndrome remains the most common chromosomal condition diagnosed in the world. Down Syndrome occurs in approximately 1 in every 700 babies.
  2. Down Syndrome is a disorder that a baby is born with. Doctors can test for it during pregnancy or diagnose it after the baby is born.
  3. Down Syndrome can’t be cured, nevertheless, doctors and other members of the health care team can treat most of the health problems related to Down Syndrome.
  4. Researchers know that Down Syndrome is caused by an extra chromosome, but no one knows for sure why Down Syndrome occurs or how many different factors play a role.
  5. One factor that increases the risk for having a baby with Down Syndrome is the mother’s age. Women who are 35 years or older when they become pregnant are more likely to have a pregnancy affected by Down Syndrome than women who become pregnant at a younger age.  However, the majority of babies with Down Syndrome, around 80%, are born to mothers less than 35 years old, because this age group gives birth most frequently.
  6. People with Down Syndrome have different physical appearance and mental challenges. People with Down Syndrome are also likely to have problems with certain organs, such as their heart, eyes, ears, digestive system, blood and they often struggle with their weight.
  7. People with Down Syndrome usually live into adulthood, but often don’t live as long as other people. Many factors can affect how long a person with Down Syndrome lives, e.g., medical problems they are born with.  Infants with Down Syndrome who also had a congenital heart defect (CHD) are five times more likely to die in the first year of life compared to infants with Down Syndrome who doesn’t have a CHD.
  8. People with Down Syndrome have mild to moderate mental damage and are slower to learn to speak than other children. Children with Down Syndrome can be included in normal schools with regular academic programmes.  Special remedial training beginning early in life can help children develop to their fullest potential.
  9. Even though people with Down Syndrome might act and look similar, each person has different abilities. We are all created unique.
  10. While behaviour, mental ability, and physical development varies from person to person, many individuals with Down Syndrome grow up to hold jobs, live independently, and enjoy normal recreational activities.

How is Down Syndrome diagnosed?

There are two basic types of tests available to detect Down Syndrome during pregnancy: screening tests and diagnostic tests.

A screening test indicates if the baby has a lower or higher chance of having Down Syndrome.  Screening tests do not provide an absolute diagnosis, but they are safer for the mother and the developing baby.  Diagnostic tests can typically detect whether or not a baby will have Down Syndrome, but they can be riskier for the mother and developing baby.  Neither screening nor diagnostic tests can predict the full impact of Down Syndrome on a baby. No one can predict this.

Screening tests

Screening tests often include a combination of a blood test, that measures the value of various substances in the mother’s blood and an ultrasound, which creates a picture of the baby.  During an ultrasound, one of the things the medical professional looks at is the fluid behind the baby’s neck.  Extra fluid in this region could indicate a genetic problem.  These screening tests can help determine the baby’s risk of Down Syndrome.  Rarely, screening tests can give an abnormal result even when there is nothing wrong with the baby.  Sometimes, the test results are normal and yet they miss a problem that does exist.

Diagnostic tests

Diagnostic tests are usually performed after a positive screening test in order to confirm a Down Syndrome diagnosis.  The healthcare professional can take put a needle into the womb to get blood from the placenta (chorionic villus sampling or CVS) or fluid from around the baby (amniocentesis) to do tests on the baby’s chromosomes

After your baby is born – Doctors may suspect Down Syndrome based on how the baby looks and to confirm do a blood test to look for an extra chromosome.  Doctors may then do other tests to see if Down Syndrome is causing other health problems, such as heart, digestion, vision, or hearing problems.