Still called Down syndrome, this disease results from a bad distribution of chromosomes during the division of the egg. Result: the affected baby has an extra chromosome 21, so it has three chromosomes 21.
The older the mother is, the greater the risk of having a child with Down syndrome.
Currently, amniocentesis is routinely offered to all women with a family history and those over 37 years of age. It allows the diagnosis of trisomy and if the parents wish the possibility of a termination of pregnancy.