In addition to the R206H mutation, almost all ACVR1 mutations detected in FOP and diffuse intrinsic pontine glioma (DIPG) also presented enhanced responsiveness to BMP, resulting in higher SMAD1/5/8 signalling upon BMP stimulation [50,58,59,60,61]. This evidence concerns the gene SMAD1 and diffuse intrinsic pontine glioma.