Fibrodysplasia ossificans progressiva caused by a different mutation in a stray cat

A 2-year-old, unneutered, female, short-haired stray cat was referred for general examination. A physical examination revealed gait abnormalities characterised by short strides and stiffness in all limbs. Radiographs showed malformations with excessive mineralisation affecting the shoulders and stifle joints. To confirm the diagnosis of fibrodysplasia ossificans progressiva, total RNA was isolated from blood samples of the cats (one cat with fibrodysplasia ossificans progressiva and one healthy cat). A single missense mutation was found in the coding sequence of the ACVR1 gene of the cat with fibrodysplasia ossificans progressiva. In this mutation, a single base was changed from guanine to cytosine. After this base change, the amino acid tryptophan replaced the amino acid cysteine. This is the first report that indicates cats with fibrodysplasia ossificans progressiva that do not show signs similar to the characteristic findings in humans have a different mutation.