What is the Down syndrome?

This syndrome occurs when the baby has three chromosomes 21 instead of two. Usually this is not the result from the transmission of the father or the mother but is due to an error in the division of the very first cells leading to an embryo. Therefore a baby without a family history can be affected.

Affected children usually have significant mental retardation and may have physical handicaps, most commonly cardiac malformations. The extend of the abnormalities can not be predicted prior to birth

Maternal age alone is relatively poor predictor of the risk of chromosomal abnormalities. Approximately 80% of trisomy 21 births occur in women under 35 years of age and 90% are due to new mutations. It is therefore necessary to add other predictive criteria’s such as serum and echographic markers.

A significant proportion of trisomic
foetuses do not reach term.
Therefore, the incidence of
trisomy 21 decline with
advancing age.