Tag Archives: trisomy 21

Down Syndrome Defined

October 22nd, 2020
Generally speaking, people have 23 pairs of chromosomes for a total of 46 chromosomes. Chromosomes are rod-like structures on DNA that store your genes, the material that carries the instructions for inherited traits such as hair color, skin color, and height. For each pair of chromosomes, you get one from your mother and one from your father. A person with Down syndrome has a third copy of one chromosome, chromosome 21, instead of the usual pair. This extra copy of…