UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory
Sphynx and Devon Rex Congenital Myasthenic Syndrome (CMS)


A mutation that causes a congenital muscle weakness in Devon Rex and Sphynx breed cats, initially reported as “Spasticity”, has been identified in the gene COLQ. The mutation results in a congenital myasthenic syndrome (CMS) similar to CMS in humans. The disease is inherited in an autosomal recessive fashion thus two copies of the mutation are necessary to observe the disease and both males and females are equally affected. Cats with a single copy are unaffected but are carriers. Moderate to severely affected cats show evidence of generalized muscle weakness, particularly following exertion, stress or excitement. Affected cats frequently adopt a characteristic “dog-begging” or “chipmunk” position, usually with their front legs resting on a convenient object. Cats with CMS generally succumb to the disease by asphyxiation due to choking on food or aspiration pneumonia by two years of age. Signs of the disease can be observed as early as of 3 weeks of age and progress slowly but occasionally do become static. The disease was first described in the UK in 1989 with detailed presentations from Australia in 1993. Affected cats have been identified in the USA and more recently across Europe. Breeding two carrier cats is predicted to produce 25% affected offspring.

The mutation causing Sphynx and Devon Rex Congenital Myasthenic Syndrome was discovered by a world-wide research team of geneticists and neurologists from the University of Missouri, the University of California Davis, the University of California San Diego, the University of Sydney and the University of Milan.

The CMS DNA test is recommended for the Devon Rex and Sphynx breeds.

Procedure for collecting a feline DNA sample

Allow 2-6 business days for results.

Results reported as:

Test Result Sphynx and Devon Rex CMS status
N/N No copies of the CMS mutation, cat is normal

1 Copy of the CMS mutation, cat is normal but is a carrier


2 copies of the CMS mutation, cat is or will be affected


Robinson R (1992) 'Spasticity'in the Devon rex cat. Veterinary Record 132: 302.

Lievesley P, Gruffydd-Jones T (1989) Episodic collapse and weakness in cats. Veterinary Annual 29:261-269

Malik R, Mepstead K, Yang F, Harper C (1993) Devon rex cats. Journal of Small Animal Practice 34:539-546

Shelton GD, Sturges B, Lyons L, Williams DC, Aleman M, Jiang Y, Mizisin A (2007) Myopathy with tubulin-reactive inclusions in two cats. Acta Neuropathol 114 (5):537-542.

Martin PT, Shelton GD, Dickinson PJ, Sturges BK, Xu R, LeCouteur RA, Guo LT, Grahn RA, Lo HP, North KN (2008) Muscular dystrophy associated with α-dystroglycan deficiency in Sphynx and Devon Rex cats. Neuromuscular Disorders 18


We appreciate the assistance of Nicholas Gustafson, the strong and long-standing dedication of cat breeders, Sybil Drummond and Pam Dowlings, Paolo Valiati, and the Italian Feline Biobank-Vetogene.

Research Funding

Funding was provided by the National Center for Research Resources R24 RR016094, the Winn Feline Foundation (W10 -014 , W11-041, MT13-010), the Phyllis and George Miller Trust (MT08-015), the University of California – Davis, Center for Companion Animal Health (2008-36-F, 2008-06-F) and the Cat Health Network (D12FE-510).

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL