Therefore, it could be predicted that the amino acid changes p.G325A seem to be related to a milder phenotype with later onset of the disease and less influence on life quality than in patients with the classical molecule, but the ossification would be affected by exogenous factors such as trauma because under exogenous stimulations, the activity of ACVR1 would be further enhanced.[9] The patients with FOP are more susceptible to stimuli, which might aggravate their symptoms of ectopic ossification. Here, ACVR1 is linked to fibrodysplasia ossificans progressiva.