DNA (deoxyribonucleic acid) is a substance containing genetic information that is found inside the center (nucleus) of cells. DNA determines what features a person inherits from his or her parents, such as blood type, hair color, eye color, and other characteristics.

Chromosomes are parts of body cells that carry the DNA. Each person's DNA contains tens of thousands of genes.

Defects in DNA are called genetic or chromosome defects or disorders. These defects may cause changes in certain body processes or functions. These changes may be harmless and undetectable, or they may cause genetic diseases or disorders, such as hemophilia, cystic fibrosis, or Down syndrome.

By	Healthwise Staff
Primary Medical Reviewer	Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer	Siobhan M. Dolan, MD, MPH - Reproductive Genetics
Last Revised	November 4, 2009