Down Syndrome and Turner's Syndrome are examples of this type of disorder. The image above is a karyotype of a person with Down Syndrome. It is a photograph of all the chromosomes in a cell, with the chromosome pairs sorted according to size. To make this karyotype, the chromosomes of a cell were stained and a photograph was taken using a microscope. Then the chromosomes were carefully cut out of the photograph with scissors, pairs were established according to their banding patterns, and the pairs were organized according to size.
Some disorders result when a mutation causes the product of a single gene to be altered or missing.
An example of this kind of disorder is sickle-cell anemia. Mutations in the beta-globin gene cause blood cells to become distorted and take on a sickle shape. When the cells have this distorted shape, they can't travel through the blood vessels easily and get clogged in the narrow passages. A normal blood cell is round, kind of shaped like a donut without the hole cut completely through. Jesse's Journey for Gene and Cell Therapy MuscleNet Huntington's Disorder Marfan Syndrome Multifactorial Disorders Multifactorial disorders result from mutations in multiple genes, often coupled with environmental causes.