ACVR1 and fibrodysplasia ossificans progressiva: Whole-genome and whole-exome sequencing for patients with DIPG have revealed that some harbor additional somatic mutations of ALK2/ACVR1, including p.R206H, p.R258G, p.G328E, p. p.G328V, p.G328W, and p.G356D, similar to the germline mutations in patients with FOP [6,7,8,9] (Figure 3).