The discovery of somatic ACVR1 mutations in DIPG identical to those found in the germline of FOP patients has not only highlighted unexpected links between neurodevelopment and chondrogenesis, but also allowed for the fast-tracked evaluation of specific ALK2 inhibitors developed for the control of heterotopic ossification in the context of childhood brain tumours24. Here, ACVR1 is linked to fibrodysplasia ossificans progressiva.