Inheritance describes the process by which genetic information is passed from parents to offspring. Understanding these patterns is essential for clinical genetics and predicting the recurrence risk of hereditary conditions.

Autosomal Dominant and Recessive Inheritance

Most human traits are dictated by genes located on the 22 pairs of autosomes.

• Autosomal Dominant: Only one mutated copy of the gene (allele) is necessary for the trait or disorder to manifest (e.g., Huntington’s Disease).

• Autosomal Recessive: Two mutated copies are required. Carriers (individuals with one mutated allele) typically show no symptoms but can pass the gene to their children (e.g., Cystic Fibrosis).

Sex-Linked and Mitochondrial Inheritance

Traits located on the X or Y chromosomes follow sex-linked patterns. Since males have only one X chromosome, they are more frequently affected by X-linked recessive disorders (e.g., Hemophilia). Furthermore, mitochondrial DNA is inherited exclusively from the mother, as the mitochondria in a zygote are derived entirely from the oocyte.