ACVR1 and cerebral malformation: The infant with the rare variant presented with limb reduction defects and brain malformation and had not yet developed flare-ups or heterotopic ossification.<h4>Conclusion</h4>This single-center cohort from Türkiye confirms the key clinical features of FOP associated with both common and rare ACVR1 variants and expands the radiological findings with notable features such as pontine malformation.