Abstract
Down Syndrome (SD), also known as Trisomy 21, is a chromosomal disorder caused by the presence of all or part of an extra-chromosome 21. This condition is the most frequent chromosomal abnormality, particularly associated with an intellectual disability. Its incidence is around 1 in each 700 neonates. This genetic disorder is attributed to the trisomy (92 to 95% of the cases), the mosaici…