For which of the following disorders would prenatal genetic diagnosis be particularly difficult?

Question

Quizplus · Accepted Answer

MERRF (Myoclonic Epilepsy with Ragged Red Fibers) is caused by mutations in mitochondrial DNA, which can vary greatly in their distribution among cells (heteroplasmy). This variability makes prenatal diagnosis particularly challenging, as the mutation load in sampled tissues (like chorionic villi or amniocytes) may not accurately reflect the mutation load in the fetus overall.

For Which of the Following Disorders Would Prenatal Genetic Diagnosis