OMIA 000119-9685 : Blood group system AB in Felis catus

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2007

Cross-species summary: Each blood group system consists of a set of blood types, each of which corresponds to a particular antigen (usually a glycoprotein) on the surface of red blood cells. The different types within a system are the result of the action of different alleles at a locus that usually encodes an enzyme that catalyses the creation of the feature of the glycoprotein unique to that type, e.g. the presence of a particular sugar at the end of a short chain of sugars.

Species-specific description: As summarised by Kehl et al. (2019): "The feline AB blood group system is composed of type A, B and C (also called AB). It is of great clinical importance, as blood incompatibilities can result in acute hemolytic transfusion reactions and hemolysis of the newborn [neonatal isoerythrolysis (NI)] due to presence of naturally occurring anti-A alloantibodies (Auer & Bell 1981; Auer et al. 1982; Giger et al. 1991; Giger 2014). The enzyme cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH; EC1.14.18.2) converts sialic acid N-acetylneuraminic acid (NeuAc; type B antigen) to N-glycolylneuraminic acid (NeuGc; type A antigen)."

History: As noted by Bighignoli et al. (2007), "CMAH represents the first blood group gene identified outside of non-human primates and humans".

Inheritance: As summarised by Kehl et al. (2019): "The CMAH locus is proposed to have three alleles with several haplotypes in the allelic series of A>a^c>b (Giger et al. 1991; Griot-Wenk & Giger 1995). Thus, genotypes A/A, A/b and A/a^c can be observed in type A cats, b/b in type B and a^c/a^c and a^c/b in type C cats."

Molecular basis: Bighignoli et al. (2007) reported haplotypes within the CMAH gene that correspond with the A and b alleles of this blood group system. The haplotypes are characterised by six mutations: "2 SNPs upstream of the start, an indel in the exon 1 5' UTR and three missense mutations in the coding region".

Gandolfi et al. (2016): "A novel variant [in CMAH], c.364C>T, was identified that is highly associated with blood type AB in Ragdoll cats and, to a lesser degree, with type AB in random bred cats"

Two new variants (c.179G>T and c.187A>G) were reported by Omi et al. (2016).

Genetic testing: Kehl et al. (2018) proposed a revised variant panel for the genotypic determination of blood group phenotype (A, B, or C (=AB)). The panel comprises four variants: c.179G>T, c.268T>A, c.364C>T, and c.1322delT, which, as shown in Table 1 of Kehl et al. (2019) enable the determination of all relevant genotypes and hence phenotypes across a wide range of breeds. These variants are labelled "2019 TYPING PANEL" in the variant table below.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
CMAH cytidine monophospho-N-acetylneuraminic acid hydroxylase Felis catus B2 NC_018727.3 (4865087..4991719) CMAH Homologene, Ensembl, NCBI gene


By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Breed(s) Variant Phenotype Gene Allele Type of Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
Blood group system AB CMAH regulatory "an indel in the exon 1 5' UTR" 2007 17553163
Blood group system AB CMAH regulatory "2 SNPs upstream of the start" 2007 17553163
Blood group system AB CMAH regulatory an indel in the exon 1 5' UTR 2007 17553163
2019 TYPING PANEL CMAH missense c.179G>T p.G60V 2016 27755584
Blood group system AB CMAH missense c.187A>G p.I63V 2016 27755584
2019 TYPING PANEL CMAH missense c.364C>T p.P122S 2016 27171395
2019 TYPING PANEL CMAH deletion, small (<=20) Felis_catus_6.2 c.1322delT p.Leu441* 2018 30235335
Blood group system AB CMAH missense Felis_catus_6.2 B2 g.4587414G>A c.139G>A p.V47M 2007 17553163 Variant coordinates obtained from or confirmed by EBI's Some Effect Predictor (VEP) tool
2019 TYPING PANEL CMAH missense Felis_catus_6.2 B2 g.4590792T>A c.268T>A p.Y89N The original (2007) designation of the c. coordinate was c.265T>A. The revised designation of c.268T>A is taken from Kehl et al. (2019) 2007 17553163 Variant coordinates obtained from or confirmed by EBI's Some Effect Predictor (VEP) tool
Blood group system AB CMAH missense Felis_catus_6.2 B2 g.4637820G>A c.1600G>A p.D534N 2007 17553163 Variant coordinates obtained from or confirmed by EBI's Some Effect Predictor (VEP) tool


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
2019 Kehl, A., Mueller, E., Giger, U., Kehl, A., Mueller, E., Giger, U. :
CMAH genotyping survey for blood types A, B and C (AB) in purpose-bred cats. Anim Genet 50:303-306, 2019. Pubmed reference: 30854707. DOI: 10.1111/age.12778.
2018 Gandolfi, B., Grahn, R.A., Gustafson, N.A., Proverbio, D., Spada, E., Adhikari, B., Cheng, J., Andrews, G., Lyons, L.A., Helps, C.R. :
Correction: A Novel Variant in CMAH Is Associated with Blood Type AB in Ragdoll Cats. PLoS One 13:e0194471, 2018. Pubmed reference: 29534111. DOI: 10.1371/journal.pone.0194471.
Kehl, A., Heimberger, K., Langbein-Detsch, I., Boehmer, S., Raj, K., Mueller, E., Giger, U. :
Molecular characterization of blood type A, B, and C (AB) in domestic cats and a CMAH genotyping scheme. PLoS One 13:e0204287, 2018. Pubmed reference: 30235335. DOI: 10.1371/journal.pone.0204287.
2017 Vieira, S.M., Ferreira, R.R.F., de Matos, A.J., Cardoso, I.M., Graça, R.M.C., Soares, A.R., Blasi-Brugué, C., Sánchez, I.M., Gopegui, R.R. :
Distribution of feline AB blood types: a review of frequencies and its implications in the Iberian Peninsula. JFMS Open Rep 3:2055116917727693, 2017. Pubmed reference: 28975035. DOI: 10.1177/2055116917727693.
2016 Gandolfi, B., Grahn, R.A., Gustafson, N.A., Proverbio, D., Spada, E., Adhikari, B., Cheng, J., Andrews, G., Lyons, L.A., Helps, C.R. :
A Novel Variant in CMAH Is Associated with Blood Type AB in Ragdoll Cats. PLoS One 11:e0154973, 2016. Pubmed reference: 27171395. DOI: 10.1371/journal.pone.0154973.
Omi, T., Nakazawa, S., Udagawa, C., Tada, N., Ochiai, K., Chong, Y.H., Kato, Y., Mitsui, H., Gin, A., Oda, H., Azakami, D., Tamura, K., Sako, T., Inagaki, T., Sakamoto, A., Tsutsui, T., Bonkobara, M., Tsuchida, S., Ikemoto, S. :
Molecular Characterization of the Cytidine Monophosphate-N-Acetylneuraminic Acid Hydroxylase (CMAH) Gene Associated with the Feline AB Blood Group System. PLoS One 11:e0165000, 2016. Pubmed reference: 27755584. DOI: 10.1371/journal.pone.0165000.
2015 Spada, E., Proverbio, D., Baggiani, L., Bagnagatti De Giorgi, G., Perego, R., Ferro, E. :
Evaluation of an immunochromatographic test for feline AB system blood typing. J Vet Emerg Crit Care (San Antonio) 26:137-41, 2015. Pubmed reference: 26264678. DOI: 10.1111/vec.12360.
2014 Fosset, F.T., Blais, M.C. :
Prevalence of feline blood groups in the Montreal area of Quebec, Canada. Can Vet J 55:1225-8, 2014. Pubmed reference: 24381340.
Giger, U. :
Blood typing and crossmatching to ensure blood compatibility Current Veterinary Therapy, Missouri: St. Louis (ed. by Bonagura JD and Twedt DC) :, 2014.
Tasker, S., Barker, E.N., Day, M.J., Helps, C.R. :
Feline blood genotyping versus phenotyping, and detection of non-AB blood type incompatibilities in UK cats. J Small Anim Pract 55:185-9, 2014. Pubmed reference: 24697343. DOI: 10.1111/jsap.12180.
2013 Proverbio, D., Spada, E., Perego, R., Della Pepa, A., Bagnagatti De Giorgi, G., Baggiani, L. :
Assessment of blood types of Ragdoll cats for transfusion purposes. Vet Clin Pathol 42:157-62, 2013. Pubmed reference: 23654225. DOI: 10.1111/vcp.12048.
2011 Seth, M., Jackson, KV., Giger, U. :
Comparison of five blood-typing methods for the feline AB blood group system. Am J Vet Res 72:203-9, 2011. Pubmed reference: 21281194. DOI: 10.2460/ajvr.72.2.203.
2009 Barrs, VR., Giger, U., Wilson, B., Chan, CT., Lingard, AE., Tran, L., Seng, A., Canfield, PJ., Beatty, JA. :
Erythrocytic pyruvate kinase deficiency and AB blood types in Australian Abyssinian and Somali cats. Aust Vet J 87:39-44, 2009. Pubmed reference: 19178476. DOI: 10.1111/j.1751-0813.2008.00381.x.
2007 Bighignoli, B., Niini, T., Grahn, RA., Pedersen, NC., Millon, LV., Polli, M., Longeri, M., Lyons, LA. :
Cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) mutations associated with the domestic cat AB blood group. BMC Genet 8:27, 2007. Pubmed reference: 17553163. DOI: 10.1186/1471-2156-8-27.
Forcada, Y., Guitian, J., Gibson, G. :
Frequencies of feline blood types at a referral hospital in the south east of England. J Small Anim Pract 48:570-3, 2007. Pubmed reference: 17608664. DOI: 10.1111/j.1748-5827.2007.00325.x.
2006 Arikan, S., Gurkan, M., Ozaytekin, E., Dodurka, T., Giger, U. :
Frequencies of blood type A, B and AB in non-pedigree domestic cats in Turkey. J Small Anim Pract 47:10-3, 2006. Pubmed reference: 16417604. DOI: 10.1111/j.1748-5827.2006.00005.x.
2005 Malik, R., Griffin, DL., White, JD., Rozmanec, M., Tisdall, PL., Foster, SF., Bell, K., Nicholas, FW. :
The prevalence of feline A/B blood types in the Sydney region. Aust Vet J 83:38-44, 2005. Pubmed reference: 15971816.
Stieger, K., Palos, H., Giger, U. :
Comparison of various blood-typing methods for the feline AB blood group system. Am J Vet Res 66:1393-9, 2005. Pubmed reference: 16173483.
2004 Hohenhaus, A.E. :
Importance of blood groups and blood group antibodies in companion animals. Transfus Med Rev 18:117-26, 2004. Pubmed reference: 15067591.
Silvestre-Ferreira, AC., Pastor, J., Almeida, O., Montoya, A. :
Frequencies of feline blood types in northern Portugal. Vet Clin Pathol 33:240-3, 2004. Pubmed reference: 15570562.
2003 Arikan, S., Duru, S.Y., Gurkan, M., Agaoglu, Z.T., Giger, U. :
Blood type A and B frequencies in Turkish Van and Angora cats in Turkey Journal of Veterinary Medicine - Series A 50:303-6, 2003. Pubmed reference: 12887623.
2002 Knottenbelt, C.M. :
The feline AB blood group system and its importance in transfusion medicine Journal of Feline Medicine & Surgery 4:69-76, 2002.
1999 Knottenbelt, C.M., Addie, D.D., Day, M.J., Mackin, A.J. :
Determination of the prevalence of feline blood types in the UK Journal of Small Animal Practice 40:115-118, 1999. Pubmed reference: 10200921.
1996 Griotwenk, M.E., Callan, M.B., Casal, M.L., Chisholmchait, A., Spitalnik, S.L., Patterson, D.F., Giger, U. :
Blood type ab in the feline ab blood group system American Journal of Veterinary Research 57:1438-1442, 1996. Pubmed reference: 8896680.
1993 Bucheler, J., Giger, U. :
Alloantibodies Against a and B Blood Types in Cats Veterinary Immunology and Immunopathology 38:283-295, 1993. Pubmed reference: 8291206.
Giger, U., Bucheler, J., Callan, M.B., Casal, M., Griotwenk, M. :
Feline Neonatal Isoerythrolysis and Transfusion Reactions Kleintierpraxis 38:715, 1993.
Griotwenk, M., Pahlsson, P., Chisholmchait, A., Spitalnik, P.F., Spitalnik, S.L., Giger, U. :
Biochemical Characterization of the Feline AB Blood Group System Animal Genetics 24:401-407, 1993. Pubmed reference: 8273913.
Leidinger, J., Leidinger, E., Giger, U. :
Distribution and Importance of Feline Blood Type-A and Type-B in Austria Wiener Tierarztliche Monatsschrift 80:10-14, 1993.
1992 Andrews, G.A., Chavey, P.S., Smith, J.E., Rich, L. :
N-Glycolylneuraminic Acid and N-Acetylneuraminic Acid Define Feline Blood Group-A and Group-B Antigens Blood 79:2485-2491, 1992. Pubmed reference: 1571562.
1991 Giger, U., Bucheler, J. :
Transfusion of Type-A and Type-B Blood to Cats Journal of the American Veterinary Medical Association 198:411-418, 1991. Pubmed reference: 2010334.
Giger, U., Bucheler, J., Patterson, D.F. :
Frequency and Inheritance of A and B Blood Types in Feline Breeds of the United-States Journal of Heredity 82:15-20, 1991. Pubmed reference: 1997588.
Giger, U., Griotwenk, M., Bucheler, J., Smith, S., Diserens, D., Hale, A., Patterson, D. :
Geographical Variation of the Feline Blood Type Frequencies in the United-States Feline Practice 19:21-27, 1991.
1990 Giger, U., Akol, K.G. :
Acute Hemolytic Transfusion Reaction in an Abyssinian Cat with Blood Type-B Journal of Veterinary Internal Medicine 4:315-316, 1990. Pubmed reference: 2074556.
1989 Giger, U., Kilrain, C.G., Filippich, L.J., Bell, K. :
Frequencies of Feline Blood Groups in the United-States Journal of the American Veterinary Medical Association 195:1230-1232, 1989. Pubmed reference: 2584120.
1982 Auer, L., Bell, K., Coates, S. :
Blood transfusion reactions in the cat. J Am Vet Med Assoc 180:729-30, 1982. Pubmed reference: 7085450.
1981 Auer, L., Bell, K. :
The AB blood group system of cats. Anim Blood Groups Biochem Genet 12:287-97, 1981. Pubmed reference: 7342803.

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