A newly described neurologic disorder is found to affect multiple family members in three generations that were available for study. In the first generation, two sisters and one brother were affected. In the second generation, all of the children of the first-generation sisters were affected, but none of the descendants of the first-generation son. In the third generation, all of the children of the affected second-generation women were affected, but none of the descendants of the second generation men. The mode of inheritance exemplified here is
In mitochondrial inheritance, inheritance is entirely maternal in transmission. Affected males do not transmit the trait to any of their children, and affected females transmit the trait to all of their children. Abnormalities of mitochondrial inheritance typically involve genes that code for enzymes of oxidative phosphorylation.
Autosomal dominant
Autosomal recessive
Mitochondrial
X-linked dominant
Genetics