Our body is made up of many cells just as a house is built with many bricks.
In the cells of human beings, there are 46 chromosomes, divided into 23 pairs and numbered from one to 23. 23 chromosomes come from the mother, 23 chromosomes come from the father. The 23 chromosomes from the mother unite with the 23 chromosomes of the father: in this way, a new cell is formed with 46 chromosomes.
The totality of these chromosomes defines the characteristics of each person. These characteristics derive partly from the parents and partly from the way they are mixed together. This is why; each of us has unique characteristics that make us different one from the other – for example the colour of one’s hair, height, skin colour and many other things.
In the pair of chromosomes number 21 of those who have Down’s syndrome, there are three chromosomes instead of two. This is the reason why Down’s syndrome is also called Trisomy 21.
Down’s syndrome is thus called because John Langdon Down, a British doctor, was the first to describe in 1862, the characteristics of people with Down’s syndrome.
In 1959, the scientist Jerome Lejeune discovered that the people with Down’s syndrome have one chromosome more in their cells.
This is why we say that Down’s syndrome is a “genetic condition”.
Down’s syndrome is not an illness and cannot be cured: it is a characteristic of a person that will not change during their lifetime.
How does one understand that somebody has Down’s syndrome?
Somebody who has Down’s syndrome has this characteristic from the time of conception that is since the time when he or she is in their mother’s belly.
To know if the child who is in the belly has Down’s syndrome two tests are possible: the Chorionic villus sampling (CVS) or amniocentesis.
Specialised doctors make the tests.
Down’s syndrome can be discovered straight away at birth when some physical characteristics of the newly born are visible (for example almond shaped eyes, the shape of hands and of feet, etc.) and through some blood tests.