Mode of inheritance in which a trait is already expressed when the triggering allele is only present singly (heterozygous). The corresponding gene is located on an autosome (not on a sex chromosome) and behaves dominantly . It is sufficient (dominant) to cause the disease. Offspring of an affected person have a 50 percent risk of inheriting the triggering allele and also being carriers of the trait.
A typical example of autosomal dominant inheritance is neurofibromatosis generalisata type I (v. Recklinghausen). If both parents have the mutation, there is a homozygous autosomal dominant inheritance. Normally, autosomal-dominant inherited diseases affect structural proteins. If > 50% of a structural protein is abnormally assembled, its function is impaired. The clinical picture becomes clinically manifest.