Title: Mode of Inheritance | ONS
Headings: Mode of Inheritance
Mode of Inheritance
Autosomal Dominant
Autosomal Recessive
X-Linked Dominant
X-Linked Recessive
Mitochondrial
Subcategory - Family History
Pedigree
Proband

Content: Mode of Inheritance | ONS
Mode of Inheritance
Mode of Inheritance is the manner in which a genetic trait or disorder is passed from one generation to the next. Autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, multifactorial, and mitochondrial inheritance are examples. Each mode of inheritance results in a characteristic pattern of affected and unaffected family members. 3
Autosomal Dominant
Autosomal dominant inheritance refers to genetic conditions that occur when a mutation is present in one copy of a given gene (i.e., the person is heterozygous). 3
Clinical Example: Hereditary Breast/Ovarian Cancer Syndrome associated with pathogenic variants in BRCA1, BRCA2, and PALB2 is a common example of an autosomal dominant genetic disorder. Autosomal Dominant Inheritance Graphic
Autosomal Recessive
Autosomal recessive inheritance refers to genetic conditions that occur only when mutations are present in both copies of a given gene (i.e., the person is homozygous for a mutation, or carries two different mutations of the same gene, a state referred to as compound heterozygosity). 3
Recessive Illustration
X-Linked Dominant
X-linked dominant inheritance refers to genetic conditions associated with mutations in genes on the X chromosome. 3
Example: A single copy of the mutation is enough to cause the disease in both males (who have one X chromosome) and females (who have two X chromosomes).