How do autosomal dominant disorders differ from autosomal recessive disorders?

Autosomal dominant disorders require only one copy of the faulty gene to manifest, while autosomal recessive disorders require two copies.

Autosomal dominant disorders and autosomal recessive disorders are both types of genetic conditions that are inherited from parents. However, they differ in the way they are passed on and the likelihood of a child developing the condition.

Autosomal dominant disorders are caused by mutations in genes on the autosomes, which are the non-sex chromosomes. In these disorders, only one copy of the faulty gene, inherited from either parent, is enough to cause the disease. This means that if one parent has the disorder, there is a 50% chance that each child will inherit it. Examples of autosomal dominant disorders include Huntington's disease and Marfan syndrome.

On the other hand, autosomal recessive disorders also involve genes on the autosomes, but two copies of the faulty gene, one from each parent, are required for the disease to manifest. This means that both parents must be carriers of the faulty gene for a child to have the disorder. If both parents are carriers, there is a 25% chance that a child will have the disorder, a 50% chance they will be a carrier, and a 25% chance they will neither have the disorder nor be a carrier. Examples of autosomal recessive disorders include cystic fibrosis and sickle cell anaemia.

In terms of symptoms, autosomal dominant disorders often appear in every generation of a family and can affect both males and females. Autosomal recessive disorders, however, may appear to skip generations, as the disorder will only manifest if a person inherits two copies of the faulty gene.

In summary, while both autosomal dominant and autosomal recessive disorders are inherited conditions involving genes on the autosomes, they differ in their inheritance patterns, the likelihood of a child developing the condition, and the way symptoms can present in families.