Approximately 90% of FOP patients share an R206H (617G>A) point mutation in the intracellular glycine- and serine-rich domain of ACVR1 (Shore et al., 2006), a type I receptor for bone morphogenetic proteins (BMPs) (Canalis et al., 2003, Gu et al., 1999, Hogan, 1996, Massague et al., 2000, Mishina et al., 1999, Miyazono et al., 2010, Mueller and Nickel, 2012, Piek et al., 1999, Urist, 1965, Wozney et al., 1988). Here, ACVR1 is linked to fibrodysplasia ossificans progressiva.