Identifying Down Syndrome

Every human being has 46 chromosomes arranged in 23 pairs. Each man's sperm has 23 chromosomes and so does each woman's egg, so that when conception occurs and the sperm fertilizes the egg, a new human being with a full complement of chromosomes is formed.

Sometimes mistakes occur and give rise to what are described as chromosomal abnormalities. Down syndrome is one of these. At conception, instead of one number 21 chromosome from the father and one from the mother coming together, a third chromosome creeps in and is then duplicated in every cell of the baby's body. Down syndrome, more accurately called trisomy 21, is the most common chromosomal abnormality, occurring approximately once in every 700 births.

How to identify Down Syndrome?

Before Birth:
Test which looks for traces of fetal DNA in the mother's blood — is highly accurate.
Screening tests: There are ultrasound tests, blood tests and a combination of the two. They just tell you how high your risk is.

After Birth:
A doctor can often make an initial diagnosis of Down syndrome at birth based on how the baby looks. The doctor may hear a heart murmur when listening to the baby's chest with a stethoscope.
A blood test can be done to check for the extra chromosome and confirm the diagnosis.
Other tests that may be done include:

• Echocardiogram to check for heart defects (usually done soon after birth)
• ECG
• X-rays of the chest and gastrointestinal tract