What type of disease occurs when an individual inherits an abnormal gene from only one parent?

The type of disease that occurs when an individual inherits an abnormal gene from only one parent is classified as an autosomal dominant disorder. In autosomal dominant inheritance, a single copy of the mutated gene is sufficient to express the phenotype associated with the disease. This means that if one parent carries the dominant allele for the disorder, there is a significant chance (typically 50%) that the offspring will inherit that allele and consequently exhibit the disease.

For example, conditions such as Huntington's disease and certain types of familial hypercholesterolemia are caused by mutations in a single gene that follow this pattern of inheritance. The presence of the abnormal gene from just one parent results in the manifestation of the disorder in the child.

In contrast, autosomal recessive disorders require both copies of the gene (one from each parent) to be mutated for the disease to manifest. This is why inherited diseases categorized as recessive, like cystic fibrosis and sickle cell anemia, do not present when only one copy of the mutated gene is present.

X-linked recessive diseases, on the other hand, are typically passed down through the X chromosome and predominantly affect males, while females may be carriers. Mitochondrial inheritance involves genes located in mitochondria, which