Burmese Head Defect

Quick Summary

Burmese head defect (BHD), or congenital frontonasal dysplasia, is an inherited defect found in Burmese cats that is characterized by improper development and subsequent malformation of the skull and facial features.

Phenotype: Burmese head defect (BHD), or congenital frontonasal dysplasia, is characterized by improper development and subsequent malformation of the skull and facial features. Kittens with BHD may be stillborn or born live, but kittens born live cannot survive for long and require euthanasia.

Mode of Inheritance: Autosomal co-dominant

Alleles: N = Normal/Unaffected, BHD= Burmese head defect

Breeds appropriate for testing: Australian Mist, Bombay, Burmese, Burmilla, European Burmese, Tonkinese

Explanation of Results:

  • Cats with N/N genoytpe will not have Burmese head defect and cannot transmit this BHD variant to any of their offspring.
  • Cats with N/BHD genotype may have shortened facial structure (brachycephaly), but will not have Burmese head defect. They will transmit this BHD variant to 50% of their offspring. Matings between two N/BHD genotype cats are predicted to produce 25% kittens with Burmese head defect.
  • Cats with BHD/BHD genotype will have Burmese head defect, a severe craniofacial defect that is incompatible with life.
Price

$40 one test per animal

Also available as part of the following packages:

$65 this test + one test from list below
$90 this test + two tests from list below
$115 this test + all tests from list below

Additional Details

The Burmese head defect mutation is common in the Contemporary lines of Burmese from the United States. A 12 bp deletion (c. 496delCTCTCAGGACTG) in the aristaless-like homobox protein 1 (ALX1) that causes a congenital craniofacial defect in Burmese cats was discovered by the Lyons Feline Genetics Research Laboratory at University of California, Davis. ALX1 mutations are known to result in frontonasal dysplasia in humans.

One copy of the mutation does not cause the craniofacial defect but may produce a shortened facial structure (brachycephaly). Cats with two copies of the mutation have the severe craniofacial defect that is incompatible with life. 5.9% of Burmese and related breeds carry the mutation. This mutation was not found in other breeds exhibiting brachycephaly.

Testing for Burmese head defect can assist owners and breeders in identifying affected and carrier cats. Breeders can use these tests as a tool to avoid breeding carriers together, which would produce 25% affected offspring.

 

Note: Burmese head defect is not related to midline defect, a genetic disease which can present head malformation among other abnormalities. Midline defect appears more common in European lines of Burmese cats and is currently under investigation. No genetic test is available at this time for midline defect.
Turnaround Time
2-6 business days
Type of Sample

Species

Cat

Type of Test

Results Reported As
Test Result Burmese Head Defect
N/N Normal. Cat does not have Burmese head defect mutation.
N/BHD

Carrier. Cat has one copy of Burmese Head Defect mutation. In breedings between carriers, 25% of kittens are expected to be affected.

BHD/BHD Affected.
References

Lyons, L. A., Erdman, C. A., Grahn, R. A., Hamilton, M. J., Carter, M. J., Helps, C. R., Alhaddad, H., & Gandolfi, B. (2016). Aristaless-Like Homeobox protein 1 (ALX1) variant associated with craniofacial structure and frontonasal dysplasia in Burmese cats. Developmental Biology, 409(2), 451-458. doi: 10.1016/j.ydbio.2015.11.015