Final answer:
FOP is caused by a gain-of-function mutation in the ACVR1 gene, leading to activin A acting as an agonist instead of its normal antagonist function. This type of mutation in an autosomal dominant disorder results in one allele being sufficient to cause the disease. the correct answer to the question is: A) Gain-of-function effect in ACVR1 such that the protein, activin A, exhibits agonist activity.
Step-by-step explanation:
Fibrodysplasia Ossificans Progressiva (FOP) is an autosomal dominant disorder which is characterized by a gain-of-function mutation in the ACVR1 gene. This mutation affects the ACVR1 protein's interaction with its ligand, such as activin A, turning it into an agonist rather than its normal antagonist role
Dominant genetic disorders are caused by just one allele and can manifest even when only one faulty gene is present. Gain-of-function mutations are typically dominant, resulting in a product that interferes with the wild-type protein's normal functions.
This mutated protein can be constitutively active, leading to disease symptoms as seen in disorders like FOP, Marfan syndrome, and Huntington's disease.
Therefore, the correct answer to the question is: A) Gain-of-function effect in ACVR1 such that the protein, activin A, exhibits agonist activity.