The Important Thing to Know About Burmese cats:

In America, American and European Burmese are dangerously inbred. 

I get about 30 kitten requests a week from people looking to replace a Burmese cat. Being a scientist, I keep track of all kinds of data.  One being age of death reported in my kitten requests. When people write me and tell me that their Burmese cat died, they tell me or I ask, how old was your cat when he or she died?  Collecting this data, I have found the following to be true. American and European Burmese cats, in America, die at age 4, 8, 12, or 18. It used to be most cats died at 18 years of age. As time has passed, and inbreeding has worsened, the life span has dropped.  Now  most of the cats I replace  died at 12 and an increasing number of cats that died at age 8 or younger. Burmese cats in America, in many instances, are not healthy cats and do not live long. And there is no doubt in my mind that as inbreeding proceeds, the life span will get is  shorter and shorter. 

Anyone looking to buy a Burmese cat should know this upfront. They should  be concerned about ill health and short life span.  Because it is a reality of Burmese cats in America today. 

Correcting the inbreeding problem is the reason I started this project. My first cats lived to be 27 and 29 and never went to the vet. One of the oldest known cats was a Burmese cat that died at 35. There was a time when Burmese cats were healthy cats. My feeling was and is, if they were once healthy cats, they can be healthy again. And the only way to take them back to health is to correct the inbreeding problem. New blood must be infused into the breed if it is to regain its status as a healthy breed. The good news is the man who created the breed, in 1930, wrote a journal article on how he created the breed, He left the recipe. So, we have the road map back to a healthy Burmese cat. 

I believe people are smart and if you provide them with accurate information, they will understand it, and act accordingly. So, I decided to present the consumer with the genetic facts of the average American Burmese cat. Once a person has seen the genetic reality of these cats, the fact they die young  makes all kinds of sense. 

To illustrate the problem with the average American or European Burmese cat, I thought it would be good to  take a look at one of my last 100% American Burmese cats, Caramela. She is my personal pet. She can be seen wearing her birthday crown hat above. She hates it but I put it on her anyway.  She is a CFA registered Burmese cat. She has a CFA registration certificate.  She is 100% legit American Burmese. If you think a cat with a CFA registration is some kind of quality assurance, what follows will make you question that. Because when you take a closer look at Caramela's family tree, it gets pretty scary. 

 Let's start by looking at Caramela's pedigree found on the Burmese Pedigree page. (www.burmesepedigrees.com) 

If you look in the upper left corner of Caramela's pedigree, you will see that the Burmese Pedigrees.com  inbreeding co-efficient calculator, calculates her level of inbreeding to be .01% . Well, that sounds pretty good.  Based on 8 generations, her inbreeding level comes out at .01%. 

If it were only a true or an accurate representation of her level of inbreeding. If you look at the next pedigree, you will see something interesting. Every single of of her great-grandparents descend from the same two cats. If you scoot through the pedigrees, back to when the breed was started,  32 generations back, both her parents descend from Wong Mau and Tai Mau, her grandparents descend from Wong Mau and Tai Mau, and her great grandparents descend from Wong Mau and Tai Mau. So, in real terms, she is 100% inbred. Have a look at her amended pedigree and you will see what I mean. 

 Every single ancestor in Caramela's pedigree descends from the same two cats. The two cats John Cheeseman Thompson used to create the breed. Every CFA registered cat descends from Wong Mau and Tai Mau. Every single one. Just to emphasis this point, I traced her grand-parents back to the beginning of the breed, and as you will see, if you follow the pedigrees, back, you will find Wong Mau and Tai Mau. 

Inbreeding is not a good thing. Ask the royal families how that worked out for them. And honestly, considering the Burmese bred was started with two cats, and they have been bred back to themselves for 90 years, its a wonder the breed did not wash up on the beach sooner.  Two cats, and their descendants, bred back to themselves for 32 generations. Its an astonishing fact. And one that basic logic suggests is a bad idea. 

My kitten requests show a clear pattern of reduced health and life span. How it worked for as long as it did, I do not know. But, what I know for sure is it is no longer working. As I said, they lived 18 years, now they live 12 years, or 8 years, or 4 years. With each generation inbreeding is compounded as are the inbreeding related health problems and reduced life span. 

And I think herein lies a trap a lot of humans fall into. Something works, and when it stops working, they are slow to embrace the new reality. 

Because my American and European Burmese cats were so shockingly inbred,  I have used as many imported Thai cats as has been humanely possible. This degree of inbreeding, the resulting ill health, and the shortened life span,  is not fixed by adding one imported cat to a line of cats. Having been doing working to improve the genetic health of the Burmese bred for over 10 years now, I would say if you want a healthy cat, the maximum American Burmese blood should be at 50% . Maximum. And preferably lower. The more Thai Burmese bred into the line, the healthier the cats will be. 

Consumers should be concerned about the health of the cat they are buying, and should ask any breeder what have they done to address the inbreeding problem. They should have done something. Because they can. I am no rocket scientist and I figured out how to import cats from Thailand. If I can do it, anyone can do it.  The problem of inbreeding caused ill health and reduces life span is real and unless it is addressed through importing new genetics, it will remain a problem. 

Now I have been told by Burmese breeders they would never use a Thai Burmese cat because it would "ruin" their look. That would be true. Thai Burmese do not look like American or European Burmese cats. But, if I had to choose between handing a pet owner a cat that will die at age 8,  and ruining the "look" of my cats, I would settle into cats that look a bit different. Passing out sick cats for the sake of vanity does not make sense to me. 

Whether a breeder does something about the inbreeding problem or does not do something about the problem is a personal choice. But, the consumer has a right to know what it is they are buying.  An inbred cat likely to have a shortened life span or a cat that has had new blood bred into the line. They have the right to know the facts and to make an informed decision.

I would hate for readers to think I am the only one that sees a problem here. Below you will find a letter from one of the top feline geneticists in the country that warns Burmese breeders there is a problem and encourages them to do something about it.  The first scientific study that reported Burmese cats were the most inbred cat in the world came out in 2007. So the information has been out there for some time. But do not take my word for it, have a read what an actual cat scientists has to say on the subject. 

And by the by, you might want to see the long list of scientific studies that follow the statement. That would be a list of studies that conclude the Burmese breed is in trouble. 

Find below Notes from Leslie Lyons on the Burmese Breed.

​Genetic Notes on the Burmese Cat Breed

27 June 2016

The Feline Genetics Laboratory, formerly of the University of California – Davis (UC Davis), now at the University of Missouri, has had long associations with Burmese breeders and veterinary researchers to define and identify the genetic mutations that cause various maladies in the Burmese breed. Many published studies (several listed below) have demonstrated that the Burmese breed has many genetic conditions, although the prevalence of these conditions is variable between countries. The Burmese in the USA are historically known for the autosomal recessive craniofacial defect that developed from the Contemporary lines of USA Burmese. Burmese carrying this condition have been identified in the UK, Europe and Australia due to the importation and use of the Contemporary lines. In addition, any other breed that has outcrossed to Contemporary Burmese has risk of the craniofacial defect. Recently, American Burmese breeders may be pursuing an organized project for heart disease.

In contrast, non - American Burmese are afflicted with several other conditions including GM2 gangliosidosis, hypokalemia, oral facial pain, diabetes, high triglycerides, a mid- line closure defect, and dermatosparaxis (stretchy skin, cutaneous asthenia, Ehlors- Danlos Syndrome). The genetic mutations for hypokalemia and GM2 gangliosidosis have been identified and like the craniofacial defect, the genetic test is available to assist breed management. Genetics studies regarding oral facial pain, diabetes, high triglycerides, flat-chested kittens, and dermatosparaxis are underway by our laboratory, in collaboration with other researchers, and independently by other researchers.

Our genetic studies have also included examining the population genetics of the different cat breeds and worldwide populations. In 2007, we published the first breed study that demonstrated that Singapura, Burmese and Birman had the lowest genetic diversity of the cat breeds we examined. A study between Singapura breeders and the UC Davis Veterinary Genetics Laboratory (VGL) supported our findings. Our recent studies demonstrate that the non-USA Burmese has as low genetic variation as the USA lines of Burmese. We strongly recommended outcrossing for all the Burmese breeds, including USA and non-USA Burmese.

Based on genetics, the Burmese breed originated from cats of Southeast Asia. Our genetic studies group cats from Thailand, Cambodia, Vietnam, Brunei and the Philippines as Southeast Asia cats. Historically, Burmese are considered to have origins from Thailand. Thus, random bred cats from Thailand and perhaps other regions of Southeast Asia are recommended as strong genetic candidates for outcrossing. Genetic tests for colors and health conditions can assist the selection of cats that may be the most advantageous for outcrossing. Other breeds with Southeast origins would also be of value to the Burmese outcrossing program, including Singapura, Bombay, and Burmese from any country. Burmilla and Asian have been crossed with Persian cats, which have western origins, thus, the use of these recent crossbred breed cats would add significant diversity, but of a different “racial” origins. Other Southeast Asian breeds include Siamese (and its breed derivatives), Korat, and Birman.

Because of our various genetic projects that include Burmese from different countries, we have been able to compare the genetics of the Burmese breed groups regionally. USA Burmese have high homozygosity (0.38), implying low genetic diversity (See attached report). The non-USA Burmese, which is a mixture of UK and Australian Burmese also have low diversity and high homozygosity (0.41), as compared to random bred cats (0.04) and other breeds. When we examine the Burmese diversity by plotting the genetic differences (termed multi-dimensional scaling (MDS), we find that the USA and non-USA Burmese do not cluster together and form independent genetic groups. The USA cats have a larger spread to their cluster as it includes Contemporary and Traditional lines of Burmese. Thus, Burmese breeders may consider crossing the Burmese cats from different countries to help improve genetic diversity.

Other genetic conditions in Southeast Asian cats include different forms of gangliosidosis in Korat and Siamese cats and pyruvate kinase deficiency in Singapura. Some Birman lines may have a susceptibility to FIP.

Overall, we have more genetic projects concerning Burmese than for any other breed and our various genetic studies have repeatedly demonstrated that Burmese, regardless of country, have amongst the lowest genetic diversity of all cat breeds. An organized and multi-faceted outcrossing program for the breed is highly recommended which includes the use of genetic testing and outcrossing to different populations and breeds.

Best regards,

Leslie A. Lyons, PhD

Text Information References

1: Kurushima JD, Lipinski MJ, Gandolfi B, Froenicke L, Grahn JC, Grahn RA, Lyons
LA. Variation of cats under domestication: genetic assignment of domestic cats to breeds and worldwide random-bred populations. Anim Genet. 2013 Jun;44(3):311-24. doi: 10.1111/age.12008. Epub 2012 Nov 22. PubMed PMID: 23171373; PubMed Central PMCID: PMC3594446.

2: Lipinski MJ, Froenicke L, Baysac KC, Billings NC, Leutenegger CM, Levy AM,
Longeri M, Niini T, Ozpinar H, Slater MR, Pedersen NC, Lyons LA. The ascent of
cat breeds: genetic evaluations of breeds and worldwide random-bred populations. Genomics. 2008 Jan;91(1):12-21. Epub 2007 Dec 3. PubMed PMID: 18060738; PubMed Central PMCID: PMC2267438.

3: Lyons LA, Erdman CA, Grahn RA, Hamilton MJ, Carter MJ, Helps CR, Alhaddad H, Gandolfi B. Aristaless-Like Homeobox protein 1 (ALX1) variant associated with craniofacial structure and frontonasal dysplasia in Burmese cats. Dev Biol. 2016
Jan 15;409(2):451-8. doi: 10.1016/j.ydbio.2015.11.015. Epub 2015 Dec 2. PubMed PMID: 26610632; PubMed Central PMCID: PMC4724490.

4: Malik R, Musca FJ, Gunew MN, Menrath VH, Simpson C, Culvenor J, Grahn RA, Helps C, Lyons LA, Gandolfi B. Periodic hypokalaemic polymyopathy in Burmese and closely related cats: a review including the latest genetic data. J Feline Med
Surg. 2015 May;17(5):417-26. doi: 10.1177/1098612X15581135. Review. PubMed PMID: 25896241.

5: O'Leary CA, Duffy DL, Gething MA, McGuckin C, Rand JS. Investigation of diabetes mellitus in Burmese cats as an inherited trait: a preliminary study. N Z
Vet J. 2013 Nov;61(6):354-8. doi: 10.1080/00480169.2013.817295. Epub 2013 Aug 5. PubMed PMID: 23909918.

6: Alhaddad H, Khan R, Grahn RA, Gandolfi B, Mullikin JC, Cole SA, Gruffydd-Jones TJ, Häggström J, Lohi H, Longeri M, Lyons LA. Extent of linkage disequilibrium in the domestic cat, Felis silvestris catus, and its breeds. PLoS One. 2013;8(1):e53537. doi: 10.1371/journal.pone.0053537. Epub 2013 Jan 7. PubMed PMID: 23308248; PubMed Central PMCID: PMC3538540.

7: Gandolfi B, Gruffydd-Jones TJ, Malik R, Cortes A, Jones BR, Helps CR, Prinzenberg EM, Erhardt G, Lyons LA. First WNK4-hypokalemia animal model identified by genome-wide association in Burmese cats. PLoS One. 2012;7(12):e53173. doi: 10.1371/journal.pone.0053173. Epub 2012 Dec 28. PubMed PMID: 23285264; PubMed Central PMCID: PMC3532348.

8: Rusbridge C, Heath S, Gunn-Moore DA, Knowler SP, Johnston N, McFadyen AK. Feline orofacial pain syndrome (FOPS): a retrospective study of 113 cases. J
Feline Med Surg. 2010 Jun;12(6):498-508. doi: 10.1016/j.jfms.2010.03.005. Epub 2010 May 6. PubMed PMID: 20451434.

9: Kluger EK, Hardman C, Govendir M, Baral RM, Sullivan DR, Snow D, Malik R. Triglyceride response following an oral fat tolerance test in Burmese cats, other pedigree cats and domestic crossbred cats. J Feline Med Surg. 2009 Feb;11(2):82-90. doi: 10.1016/j.jfms.2008.05.005. Epub 2008 Jul 30. PubMed PMID: 18667349.

10: Lederer R, Rand JS, Jonsson NN, Hughes IP, Morton JM. Frequency of feline diabetes mellitus and breed predisposition in domestic cats in Australia. Vet J. 2009 Feb;179(2):254-8. Epub 2007 Dec 21. PubMed PMID: 18155627.

11: McCann TM, Simpson KE, Shaw DJ, Butt JA, Gunn-Moore DA. Feline diabetes mellitus in the UK: the prevalence within an insured cat population and a questionnaire-based putative risk factor analysis. J Feline Med Surg. 2007 Aug;9(4):289-99. Epub 2007 Mar 27. PubMed PMID: 17392005.

12: Lantinga E, Kooistra HS, van Nes JJ. [Periodic muscle weakness and cervical ventroflexion caused by hypokalemia in a Burmese cat]. Tijdschr Diergeneeskd. 1998 Jul 15-Aug 1;123(14-15):435-7. Dutch. PubMed PMID: 9700861.

13: Rand JS, Bobbermien LM, Hendrikz JK, Copland M. Over representation of Burmese cats with diabetes mellitus. Aust Vet J. 1997 Jun;75(6):402-5. PubMed PMID: 9247686.

14: Sponenberg DP, Graf-Webster E. Hereditary meningoencephalocele in Burmese cats. J Hered. 1986 Jan-Feb;77(1):60. PubMed PMID: 2937834.

15: Hansen N, Foster SF, Burrows AK, Mackie J, Malik R. Cutaneous asthenia (Ehlers-Danlos-like syndrome) of Burmese cats. J Feline Med Surg. 2015 Nov;17(11):954-63. doi: 10.1177/1098612X15610683. PubMed PMID: 26486982.

16: Bradbury AM, Morrison NE, Hwang M, Cox NR, Baker HJ, Martin DR. Neurodegenerative lysosomal storage disease in European Burmese cats with hexosaminidase beta-subunit deficiency. Mol Genet Metab. 2009 May;97(1):53-9. doi: 10.1016/j.ymgme.2009.01.003. Epub 2009 Feb 23. PubMed PMID: 19231264.

17: Lyons LA, Imes DL, Rah HC, Grahn RA. Tyrosinase mutations associated with Siamese and Burmese patterns in the domestic cat (Felis catus). Anim Genet. 2005 Apr;36(2):119-26. PubMed PMID: 15771720.

Table References

1. Eizirik E, Yuhki N, Johnson WE, et al. Molecular genetics and evolution of melanism in the cat family. Curr Biol 2003; 13: 448-453.
2. Gershony LC, Penedo MC, Davis BW, et al. Who's behind that mask and cape? The Asian leopard cat's Agouti (ASIP) allele likely affects coat colour phenotype in the Bengal cat breed. Anim Genet 2014; 45: 893-897.

3. Lyons LA, Foe IT, Rah HC, et al. Chocolate coated cats: TYRP1 mutations for brown color in domestic cats. Mamm Genome 2005; 16: 356-366.
4. Schmidt-Kuntzel A, Eizirik E, O'Brien SJ, et al. Tyrosinase and tyrosinase related protein 1 alleles specify domestic cat coat color phenotypes of the albino and Brownloci. J Hered 2005; 96: 289-301.

5. Imes DL, Geary LA, Grahn RA, et al. Albinism in the domestic cat (Felis catus) is associated with a tyrosinase (TYR) mutation. Anim Genet 2006; 37: 175-178.
6. Lyons LA, Imes DL, Rah HC, et al. Tyrosinase mutations associated with Siamese and Burmese patterns in the domestic cat (Felis catus). Animal Genet 2005; 36: 119-126.

7. Ishida Y, David VA, Eizirik E, et al. A homozygous single-base deletion in MLPH causes the dilute coat color phenotype in the domestic cat. Genomics 2006.
8. Peterschmitt M, Grain F, Arnaud B, et al. Mutation in the melanocortin 1 receptor is associated with amber colour in the Norwegian Forest Cat. Anim Genet 2009; 40: 547-552. 9. Lyons LA, Creighton EK, Alhaddad H, et al. Whole Genome Sequencing Identifies an AIPL1 Variant in Persian Cats as a New Model for Leber's Congenital Amaurosis. BMC Genome 2016; (In press)).

10. Drogemuller C, Rufenacht S, Wichert B, et al. Mutations within the FGF5 gene are associated with hair length in cats. Anim Genet 2007; 38: 218-221.
11. Kehler JS, David VA, Schaffer AA, et al. Four independent mutations in the feline fibroblast growth factor 5 gene determine the long-haired phenotype in domestic cats. J Hered 2007; 98: 555-566.

12. Kaelin CB, Xu X, Hong LZ, et al. Specifying and sustaining pigmentation patterns in domestic and wild cats. Science 2012; 337: 1536-1541.
13. David VA, Menotti-Raymond M, Wallace AC, et al. Endogenous retrovirus insertion in the KIT oncogene determines White and white Spotting in domestic cats. G3 2014; 4: 1881-1891.

14. Bighignoli B, Niini T, Grahn RA, et al. Cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) mutations associated with the domestic cat AB blood group.BMC Genet 2007; 8: 27.
15. Gandolfi B, Grahn RA, Gustafson N, et al. Type it! The genetic characterization of CMAH in Ragdoll blood type AB. BMC veterinary research 2016; (Submitted).

16. Lyons LA, Erdman CA, Grahn RA, et al. Aristaless-Like Homeobox protein 1 (ALX1) variant associated with craniofacial structure and frontonasal dysplasia in Burmese cats.Dev Biol 2015.
17. De Maria R, Divari S, Bo S, et al. Beta-galactosidase deficiency in a Korat cat: a new form of feline GM1-gangliosidosis. . Acta Neuropathol (Berl) 1998; 96: 307-314.

18. Bradbury AM, Morrison NE, Hwang M, et al. Neurodegenerative lysosomal storage disease in European Burmese cats with hexosaminidase beta-subunit deficiency. Mol Genet Metab 2009; 97: 53-59.
19. Muldoon LL, Neuwelt EA, Pagel MA, et al. Characterization of the molecular defect in a feline model for type II GM2-gangliosidosis (Sandhoff disease). Am J Pathol 1994; 144: 1109-1118.

20. Gandolfi B, Gruffydd-Jones TJ, Malik R, et al. First WNK4-hypokalemia animal model identified by genome-wide association in Burmese cats. PloS one 2012; 7: e53173.
21. Grahn RA, Grahn JC, Penedo MC, et al. Erythrocyte pyruvate kinase deficiency mutation identified in multiple breeds of domestic cats. BMC veterinary research 2012; 8: 207.
executive that includes what they do, how long they’ve been at it, and what got them to where they are.

I started with Caramela and I will end with Caramela, 

As you can see, she has gained a little weight in her old age. As she is 100% inbred American CFA registered Burmese, I do not expect her to be with me for as long as I would like. Her uncle, Bruce Lee 2, died at age twelve this year. After two terrible, terrible years of ill health, he finally passed away this Thanksgiving. It was heart breaking to see him suffer so much and to be happy/sad his suffering came to an end. He was two years older and a generation younger than Caramela. His generation seems to live to be about 12. Caramela's generation seems to struggle to make it to 10. So far she is healthy, but, the odds are stacked against her. 

She is in my line, literally, but her great great grandchildren are now 75% imported Thai Burmese. Her many offspring will live longer and healthier lives than she is destined to live. 

My advice to consumers is this. Be aware there is a problem with inbred American Burmese cats. Be aware neither CFA not TICA have health or longevity as a criteria for registration. Being a CFA or a TICA registered cat is by no means a quality assurance. Consumers need to ask breeders what they have done about the problem, and wait to here their answer. And then make an informed decision.