We believe in presuming competence, inspiring inclusion, and empowering individuals to reach their fullest potential. Down syndrome is a chromosomal disorder characterized by the presence of an extra #21 chromosome. Instead of having 46 chromosomes in each of his/her cells, a person with Down syndrome has 47. The extra chromosome may be derived from either the egg or the sperm. It is believed that during cell division of a sperm or egg, the two #21 chromosomes do not separate properly (non-disjunction). Thus, one cell will have an extra #21 chromosome, which later, if united with a normal germ cell, which has among others one #21 chromosome, may lead to trisomy 21. The first cell at conception then has 47 chromosomes instead of "normal set" of 46 chromosomes. When this cell with three #21 chromosomes continues to multiply, and the pregnancy is carried to term, a baby with Down syndrome will be born. This form of chromosome error, trisomy 21, is found in about 95% of persons with Down syndrome.
