Test Detail

Molecular test for congenital myasthenic syndrome (CMS) in the Devon Rex and Sphynx cat, a hereditary disease of the neuromuscular junction caused by a deficiency of collagen-associated acetylcholinesterase (COLQ). It produces generalised muscle weakness and exercise intolerance due to defective neuromuscular transmission, and compromises ambulation, feeding and quality of life. The test reports clear/carrier/affected status.

Devon Rex and Sphynx. Allele frequency ~2.0% in Devon Rex and ~3.7% carriers in a European Sphynx panel; no carriers were found in more than 350 cats of other breeds.

- Genotype breeding animals before mating\n- Do not mate carrier×carrier (25% risk of affected homozygotes); carrier×clear produces 0% affected and 50% carriers\n- An affected animal must not be bred; a carrier may be mated to a clear animal without producing affected offspring\n- After a confirmed clinical case, do not repeat the parental mating and communicate the status to the buyer

Differential diagnosis with acquired myasthenia gravis (anti-acetylcholine receptor antibodies, rare in cats) and with hereditary myopathies. Worsening of weakness after the administration of anticholinesterases (e.g. in the neostigmine test) is a diagnostic clue for COLQ-related CMS. In this form, acetylcholinesterase inhibitors may worsen the weakness and are not the treatment of choice; management relies on sympathomimetics/β2 agonists (e.g. ephedrine, salbutamol) and 3,4-diaminopyridine, based on experience in human COLQ-related CMS.

1. Abitbol M, et al. A COLQ missense mutation in Sphynx and Devon Rex cats with congenital myasthenic syndrome. PLoS One. 2015;10(9):e0137019. PMID: 26327126
2. Gandolfi B, et al. COLQ variant associated with Devon Rex and Sphynx feline hereditary myopathy. Anim Genet. 2015;46(6):711-715. PMID: 26374066
3. Shelton GD. Myasthenia gravis and congenital myasthenic syndromes in dogs and cats: a history and mini-review. Neuromuscul Disord. 2016;26(6):331-334. PMID: 27080328