Question

Which of the following is a characteristic of mitochondrial disorders?

(A) They are inherited in a Mendelian fashion.
(B) There is a threshold level of mutated mitochondria that must be reached before clinical symptoms appear.
(C) All cell types in the body are equally affected by mitochondrial disorders.
(D) The degree of severity is the same for most affected individuals.

Answer 1

The correct characteristic of mitochondrial disorders is that clinical symptoms appear after a certain level of mutated mitochondria is reached, leading to a range of severities and symptoms.

Step-by-step explanation:

The characteristic of mitochondrial disorders that is correct among the options provided is (B) There is a threshold level of mutated mitochondria that must be reached before clinical symptoms appear. Mitochondrial disorders, which can arise from mutations in nuclear or mitochondrial DNA, impact cellular respiration processes significantly. Not all cells are equally affected, as mutated mitochondria are passed down during cell division in varying amounts, leading to a wide range of symptoms and severities even within the same family. Mitochondrial diseases can lead to symptoms such as muscle weakness, lack of coordination, stroke-like episodes, and loss of vision and hearing, with most people being diagnosed in childhood or early adulthood.