Fibrodysplasia ossificans
Gene: ACVR1
Transmission: Autosomal, probably dominant
The animal only has to have one copy of the mutation to be at risk of developing hypertrophic cardiomyopathy. Animals with two copies of the mutation generally have more severe symptoms and an earlier onset of the disease than animals with just one copy of the mutation. Offspring are potentially at risk of developing the disease if at least one parent carries the mutation.
Mutation: Substitution, ACVR1 gene; c.617 G>A, p.(R206H), chr.C1
Medical system: Muscular, skeletal
Breeds: Domestic Cat, Himalayan, Maine Coon, Savannah
Age of onset of symptoms: Early onset, from 4 to 6 months, to late onset, at 6 years
Fibrodysplasia ossificans progressiva in cats is a rare genetic disease characterized by bone mineralization of muscles and muscle-supporting tissues and leading to loss of motility in the animal. The animal will present with stiffness and a reluctance to run and jump. A biopsy and X-ray will show the presence of bony tissue in muscle-supporting tissues such as tendons and epimysium. The disease is progressive, worsening within a few months in the majority of cases reported. However, only ten cases of fibrodysplasia ossificans in the cat have been reported in the scientific literature over the last thirty years, most likely due to spontaneous dominant mutations that are self-limiting. The ACVR1 gene codes for the activin A receptor type 1 protein. The mutation identified as causing fibrodysplasia ossificans in the cat was identified in two domestic cats based on presenting clinical symptoms and a candidate gene approach and is identical to a mutation that causes the disease in humans.
References:
Jacobsen KL, Wiebe V, Davidson AP, et al. (2022) Use of enrofloxacin and hydrotherapy in the management of fibrodysplasia ossificans progressiva (fop) in a Savannah cat. Top Companion Anim Med. 52:100757. [pm/36592860]
Casal ML, Engiles JB, Zakosek P, et al. (2019) Identification of the identical human mutation in ACVR1 in 2 cats with fibrodysplasia ossificans progressiva. Vet Pathol 56:614-618. [pm/31007133]
Klang A, Kneissl S, Glänzel R, Fuchs‐Baumgartinger A. (2013) Imaging diagnosis: fibrodysplasia ossificans progressiva in a cat. Vet Radiol Ultrasound 54:532-5. [pm/23578335]
Contributed by: Andy Yin and Lindsey Gillespie, Class of 2028, Faculty of Veterinary Medicine, University of Montreal. (Translation DWS).