A man and his sister are both affected with a mitochondrial disorder. Because the sister has two children who also have the disorder, the man is concerned about thepossibility of also having children with the disorder. What is the estimated risk for each pregnancy of this man producing a child with the same mitochondrial disorder that he has if his wife does not have a mitochondrial disorder?
A)100%
B)50%
C)25%
D)0%

Question

Quizplus · Accepted Answer

All mitochondria at conception come from the egg because they are located in the egg's cytoplasm. The sperm has no cytoplasmic mitochondria. Therefore, most mitochondrial disorders can only be inherited from a woman with the disorder and not from a man with the disorder.

A Man and His Sister Are Both Affected with a Mitochondrial