In the Abyssinian and Somali breeds as well as random bred domestic shorthair cats there is a form of inherited hemolytic anemia caused by alterations in the enzyme erythrocyte pyruvate kinase. This enzyme is essential for normal function of red blood cells (erythrocytes). Mutations in PKLR, the gene encoding regulatory glycolytic enzyme pyruvate kinase (PK), result in the disease. The first documented case of feline PK deficiency was in an Abyssinian cat. Subsequent reports demonstrated that Somalis, a longhaired variety of the Abyssinian, as well as random bred domestic shorthairs, may also suffer from PK deficiency. The disturbance of PK results in decreased erythrocyte life span resulting in anemia. The anemia exhibits as a chronic, intermittent, hemolytic anemia. The most common clinical signs are lethargy, diarrhea, pale mucous membranes, poor appetite, poor coat quality, weight loss, icterus, and sporadic splenomegaly.
In looking at an affected group of 25 cats, clinical signs were first noted as early as 6 months and as late as 5 years of age. PK deficiency has an autosomal recessive inheritance with variability of onset and severity of clinical signs. In this study, sequence analysis of PKLR revealed an intron 5 single nucleotide polymorphism (SNP) at position 304 consistent with the disease phenotype in Abyssinian and Somali cats. The disease-associated SNP presence and frequency was determined by analysis in 14,179 cats representing 40 breeds or populations. Based on the study’s findings, the authors recommend PK testing for several breeds including the Bengal, Egyptian Mau, La Perm, Maine Coon, Norwegian Forest Cat, Savannah, Siberian, and Singapura, in addition to Abyssinian and Somali. Breeds known to have been derived from Abyssinian crosses such as the Ocicat, and new breeds developed with out-crossing programs using affected breeds should be tested as well. In time, expanded testing methods along with removal of affected individuals from the breeding population may enable the selective elimination of the PK deficiency-associated SNP in domestic cat populations. [VT]
See also: Barrs V, Giger U, Wilson B, et al. Erythrocytic pyruvate kinase deficiency and AB blood types in Australian Abyssinian and Somali cats. Aust Vet J. 2009; 87: 39-44. [Free, full text article]