Fibrodysplasia Ossificans

Fibrodysplasia ossificans progressiva (FOP) is a type of musculoskeletal disease characterized by bony deposits or the ossification of muscle tissue. It is a rare genetic progressive disorder that affects humans and animals. FOP is associated with dysregulated production of bone morphogenetic protein 4 (BMP4), which plays an important role in the growth and development of numerous tissues, including bone, brain, and spinal cord. In dogs and cats, the disorder is marked by chronic, painful wounds and calcified deposits in the paws and abdomen.

The disorder typically affects young and middle-aged animals of both sexes. Signs include progressive weakness and stiffness of gait, enlargement of limb muscles, muscle pain, visible limb swelling, atrophy of the muscles, and limited mobility of all joints. Since it is a progressive disorder, the prognosis is guarded to poor. Inheritance of the disorder has not yet been demonstrated. At present, there is no effective prevention or treatment. The recent discovery of the FOP gene establishes a critical milestone in understanding FOP and reveals a target for drug development.


  1. A Practical Guide to Canine and Feline Neurology. Curtis W. Dewey
  2. Fibrodysplasia ossificans progressiva-like condition in a cat.Asano K, Sakata A, Shibuya H, Kitagawa M, Teshima K, Kato Y, Sasaki Y, Kutara K, Seki M, Edamura K, Sato T, Tanaka S.

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