Consider a mating between a normal individual and an affected individual. The normal individual has a normal genotype. The affected individual has a mutant gene. Hence, 50% of the progeny will express the dominant mutant gene. The remaining 50% of progeny will be normal. The individuals showing a dominant mutant gene are known as heterozygotes. Consider another case of mating between both the affected parents. 25% of the offspring will show both the mutant genes. Hence, they are known as severely affected individuals. 50% of the progeny will show one mutant gene. Hence, they are known as affected individuals. The remaining 25% of individuals show a normal genotype.

There are total 22 pairs of autosomes in humans. The non-sex chromosomes are known as autosomes. The anomalies associated with the autosomes are known as autosomal anomalies or autosomal abnormalities. The mutations in the genes present on these autosomes decide the inheritance of a particular disease. An autosome consists of a mutant gene in autosomal disorders. The mutant gene expresses the disorder even though present in a single dose. Autosomal diseases involve the presence of a mutant gene on one of the chromosomes in a pair.

Following are the characteristics of an autosomal dominant inheritance:

1. Both the sexes equally get affected with the autosomal dominant traits.

2. The genes or the traits get transmitted in four possible ways such as male to male, male to female, female to female and female to male types of transmissions.

3. Follows no skipping of generations

4. Mostly seen in all the generations

5. In most of the cases, the proband has at least one affected parent

6. New autosomal dominant mutations occur newly in a generation due to some error in the gametogenesis in the parent. The child having new mutations passes on the traits to the next generations

7. Those having the abnormal genes on the autosomes only pass on the trait to the next generation

8. Those having normal genes and exhibiting normal phenotype do not pass on the trait

9. The proportion of the normal and the affected individuals in a population is almost the same.

10. An autosomal dominant gene mostly affects one part of the body. However, it may also lead to a disorder where many parts of the body get affected. One mutated gene can affect many phenotypes. A phenomenon in which one gene produces many phenotypes is known as pleiotropy. Hence, the autosomal dominant gene may exhibit pleiotropy.

11. The expression of the autosomal dominant gene varies from person to person. The phenotype also varies.