This site is intended for US Healthcare Professionals only.
This site is intended for US Healthcare Professionals only.

Key Signs and Symptoms of FOP:


Bilateral malformation of the great toes


Heterotopic ossification (HO)

Minor skeletal malformations, brachydactyly

If you see one or more of the key signs, make the association. Think FOP.


Pathognomonic Signs of FOP1

FOP can be definitively diagnosed upon clinical observation of bilateral malformation of the great toes along with evidence of heterotopic ossification (HO).

Genetic Testing for FOP

In 2006, the ACVR1 (R206H) mutation was discovered as the cause of FOP. Most patients with FOP (approximately 97%) have the same point mutation, R206H.1,2 Genetic testing for various ACVR1 mutations in FOP is available from specialized laboratories.


  1. Kaplan FS, et al. Clin Rev Bone Miner Metab. 2005; 3:183–188.
  2. Chakkalakal SA et al. J Bone Miner Res 2016;31:1666-1675.
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Please always consult a healthcare professional if you require healthcare advice or if you have any specific concerns regarding Fibrodysplasia Ossificans Progressiva. The information provided here is not intended to replace professional advice. This website has been developed by Ipsen in collaboration with those living with Fibrodysplasia Ossificans Progressiva and the healthcare professionals who care for them. Ipsen would like to thank everyone for their valuable insights and stories. All names used on this website are not necessarily real names. Visit our website for more information about us, or to contact us directly. Website design and development by Kanga Health Ltd. Website reference NON-US-002031 December 2020