Mitochondrial inheritance means the pathogenic variant is located in a specific type of DNA, called mtDNA. mtDNA is found within the cell's mitochondria. Mitochondria are tiny structures that produce energy for the body. Pathogenic variants within mtDNA can prevent the mitochondria from working properly.
During human conception, egg cells, or the cells that come from the female parent, provide mitochondria. If a female parent is affected by a mitochondrial pathogenic variant, there is a 100% chance their child inherits the pathogenic variant. However, the child may or may not be affected by the disease. A male parent cannot pass a mitochondrial pathogenic variant to children.Learn more about inheritance patterns from the National Library of Medicine (NLM).