Autosomal dominance is a pattern of inheritance characteristic of some genetic diseases. "Autosomal" means that the gene in question is located on one of the numbered, or non-sex, chromosomes. "Dominant" means that a single copy of the disease-associated mutation is enough to cause the disease. This is in contrast to a recessive disorder, where two copies of the mutation are needed to cause the disease. Huntington's disease is a common example of an autosomal dominant genetic disorder.
Autosomal dominant refers to how a particular trait is inherited. The word autosome refers to the non-sex chromosomes. In humans, those are Chromosomes 1 through 22. So an autosomal trait is one that occurs due to a mutation on Chromosomes 1 through 22. Dominant means that you only need one copy of a mutation in order to be effective. Some autosomal dominant traits that individuals may be familiar with are neourofibromitosis Type I, Huntington disease, and Marfan syndrome.- Suzanne Hart, Ph.D.