Question

Heteroplasmy is associated with:

A Difficulty in making a prenatal diagnosis
B Random inactivation of the X chromosome
C Repeat instability
D Increased severity in later generations
E All of the above

Answer 1

Heteroplasmy is primarily associated with difficulty in making a prenatal diagnosis because of the presence of different mitochondrial DNA populations within an individual's cells. This makes it challenging to represent the organism's overall genetic makeup accurately in diagnostic tests.

Step-by-step explanation:

Heteroplasmy is associated with difficulty in making a prenatal diagnosis. This condition arises when there are multiple populations of mitochondria within a single individual's cells, each with different genetic makeups. Consequently, it poses challenges for prenatal diagnostic procedures because the genetic composition in the tested sample may not represent the entire organism's cellular makeup accurately.

Disorders related to the X chromosome, such as Turner syndrome, or conditions like Down syndrome are also examples where heteroplasmy could theoretically play a role, given the presence of varying genetic information. Yet, the term heteroplasmy is more commonly used in the context of mitochondrial, rather than chromosomal, disorders.

Inversions, translocations, and repeat instabilities are other forms of genetic aberrations that do not align with heteroplasmy but can impact chromosomal health and prenatal diagnostic outcomes. Therefore, the correct answer to the question is: A Difficulty in making a prenatal diagnosis.