The Burmese head defect (craniofacial) mutation affects the development of the head and facial areas in affected cats. The mutation is recessive, meaning that two copies are required for the head defect to develop. This genotype is incompatible with life and kittens are still born. Cats with one copy of the mutation do not have the head defect but may have a shortened facial structure (brachycephaly) and can pass the mutation to their offspring.
The Burmese head defect mutation is common in lines of Burmese in the United States (personal communication Prof L Lyons). A recent study undertaken by Dr Chris Helps at Langford Veterinary Services has shown the prevalence of the head defect mutation in approximately 800 European and UK Burmese was around 1%.
We can now test for the Burmese head defect mutation to enable breeders to identify carrier cats and prevent breeding between them, which can produce affected kittens.
Please note: the Burmese head defect genetic test detects the recently identified mutation found in lines of Burmese in the USA and, as mentioned above, in a low percentage of European Burmese cats that are probably related to cats in the USA. More information about this defect, together with pictures of affected kittens, can be found here. A similar congenital defect (Midline defect) has been reported in lines of European Burmese. We have recently shown that this defect is not caused by the mutation that causes the Burmese head defect. Currently it is not possible to genetically test for the Midline defect found in European Burmese.
A Normal Burmese head defect genetic test result means that the cat does not have the known genetic mutation causing the Burmese head defect.
A Carrier Burmese head defect genetic test result means that the cat has one copy of the Burmese head defect mutation. The cat will not have the head defect, but may pass the mutation to their offspring.
An Affected Burmese head defect genetic test result means that the cat has two copies of the Burmese head defect mutation. The cat will have the head defect.
Each certificate we issue will specify whether the cat is Normal, Carrier or Affected for the known Burmese head defect mutation.