4. There are 3 types of Down syndrome
One of the significant facts about Down syndrome is that there are 3 kinds. To get a more in-depth idea of these types, we need to know about two other concepts:
- Our chromosomes are in every cell of our body.
- When experts analyze chromosomes (karyotyping), they identify them by number; hence we have chromosome pair #1, chromosome pair #2, up to chromosome pair #23.
Now, here are the 3 types of Down syndrome:
- Trisomy 21 – The most common type occurring in about 95% of Down syndrome cases. Instead of just two, there are three chromosome 21; it occurs in all the body cells.
- Translocation – This accounts for about 4% of Down syndrome cases. It happens when an extra part of or a full chromosome 21 can be found in another pair. For instance, there is an extra chromosome 21 in what was supposed to be pair #14.
- Mosaicism – The rarest type. It happens when some cells in the body have 46 chromosomes, while other cells have 47 because of an extra chromosome 21.
5. There’s no way to “predict” the full impact of Down syndrome on the child
A mother can undergo screening tests to assess the risk of having a baby with Down syndrome; however, these tests (ultrasound, blood tests, etc.) cannot offer a definitive diagnosis.
The diagnosis options are to check their amniotic fluid (amniocentesis) or cell samples from the placenta (chorionic villus sampling) for abnormal chromosomes. The concern is that these tests often have risks for both mother and child.
At birth, the doctors can look for the physical signs; likewise, they can also take blood samples to do karyotyping.
But even with these strategies, there’s still no way to predict how the condition will influence a child’s life.