• is validated for all cat breeds except Domestic Shorthair, and
  
• can now check for more 'b' allele variants than ever before including the b3 which was identified by researchers at Laboklin, and
  
• can check for the 'c' allele which is resposnible for the AB serotyp, and
  
• only available at Laboklin

A recent study at Laboklin identified a number of new variants involved in determining the different blood groups in cats. Our Genetic Blood Group DNA test has now been updated with the new variants and as a result we can now screen all cat breeds except Domestic Shorthair for genetic blood groups. The updated test can detect the 'b' mutation which is reposnible for blood group 'B' more accurately than before and in more breeds, and the 'c' mutation which is repsonsible for blood group 'AB' in Ragdoll and Bengal can now be detected.

The test is valid for all cat breeds except: Domestic Shorthair.

The new improved test is more comperhensive than any other commercially available tests.

Neonatal isoerythrolysis (NI):

This incompatibility reaction, especially important for breeders, is neonatal isoerythrolysis (NI). Neonatal isoerythrolysis in cats, also called fading kitten syndrome, is a dissolution of the red blood cells.

Only new born cats with blood groups A or AB (also known as C) whose mother has blood group B are affected by NI. In pedigree catteries, neonatal isoerythrolysis may occur in first-born and multiparous queens with blood group B, if they are mated to toms having blood groups A or AB (also known as C).

The kittens, with blood group A and AB (also known as C), which were born healthy, however, take up the mother's antibodies with the colostrum. These bind to the erythrocytes, which are then destroyed. Anaemia, excretion of protein in the urine and jaundice are the consequences, so that the kittens usually die within the first week of life. In some cases, the intestinal barrier is already closed at the time of birth, so that the absorption of the immunoglobulins by the kitten is prevented. Therefore, some theoretically at-risk kittens may not develop neonatal isoerythrolysis. Thus, not all kittens with blood groups A and C whose mother is type B develop NI.

Good to know Blood type B kittens whose mothers have blood group A do not develop NI. This is due to the low anti-B antibody titre in blood group A queens.

As a rule, new born kittens with clinical symptoms cannot be treated successfully. However, neonatal isoerythrolysis can be prevented by determining the blood groups of possible breeding partners in advance and avoiding mating between queens with blood group B and toms with types groups A or AB (also known as C). However, if such mating does occur, the kittens with blood groups A or AB (also known as C) should be separated from their type B mother in the first 16-24 hours after birth to prevent antibody uptake before the intestinal barrier is closed. For the genetic blood group determination, Laboklin requires either an EDTA blood sample (0.5 - 1 ml) or 2 cheek swabs. The sample run time after sample arrival is approx. 3-5 working days.

The differences between blood types is determined by the activity of cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH). CMAH is only active in type A erythrocytes and either absent or non-functional in type B red blood cells. This inactivity is caused by different mutations in the CMAH gene.

The original mutation which is causative for blood type B was found by Leslie A. Lyons research team and allows for correctly identifying 86 % of all type B cats which still left 14 % of serological type B cats misidentified, especially Ragdolls and Turkish Angora cats.

Our own research shows that additional screening for two other novel mutations correctly identifies 99% of all type B cats. By determining just these two novel variants all type A and B Ragdolls were identified correctly. These two mutations were also found to be causative for blood type B in Turkish Angora, Neva Masquerade, Scottish Fold as well as Domestic Shorthair cats

Leslie A. Lyons research team found another variant in CMAH which is responsible for blood type C (AB) in Ragdolls. We found that this specific mutation is not exclusively found in Ragdolls even though it is rare in other breeds. Type C Bengal cats could also be correctly identified by this mutation and it was also found in British Shorthairs, Maine Coons and Scottish Fold cats.

Since 2017 we practice a genotyping scheme with four variants, three of those to identify blood type B cats correctly and one additional to include the most common variant for blood type C.

The test now detects three genetic variants for the 'b' allele (268T>A, 179G>T, 1322delT) and one variant for the 'c' allele (364C>T).

The 3 'b' variants are also known as b1, b2, and b3.

PK - The Mutation-based Test and its Advantages The genetic defect leading to the disease has been identified. By DNA testing the responsible mutation can be shown directly. This method provides a very high accuracy test and can be done at any age. It offers the possibility to distinguish not only between affected and clear dogs, but also to identify clinically healthy carriers. This is an essential information for controlling the disease in the breed as carriers are able to spread the disease in the population, but can not be identified by means of common laboratory diagnostic. If a particularly valuable animal turns out to be a carrier, it can be bred to a non-affected animal, and non-carrier puppies can be saved for the next round of breeding.

the dilute gene is responsible for the intensity of the coat colour by affecting the amount of pigments in the hair shaft. The pigment granules are clumped and distributed unevenly along the hair shaft, resulting in a clear colour.
 

The "dilute" phenotype in domestic cats affects both eumelanin and phaeomelanin pathway. The dilution of black results in a grey ("blue") phenotype, while dilute combined with orange appears as a cream colour, chocolate results in lilac, cinnamon results in fawn and orange in creme.

All coat colours and coat colour variants are inherited as an autosomal-recessive trait. The DNA test offers the detection of hidden colours or colour variants of these colours.

Siamese and Burmese patterns

The Siamese pattern is reponsible for a phenotype representing a mild form of albinism. This temperature-sensitive mutation produces normal colour pigment only at the cooler extremities of the body, causing a mask of the face as well as darkened paws and tail. The Siamese pattern is also called mask factor or point, since normal pigmentation occurs only at the cooler points of the body.

The Burmese pattern, the mildest form of albinism, is characterized by a normal pigmentation of the extremities and a slight shading of normal body colour.

Two mutations in the gene encoding the enzyme tyrosinase which is required for melanin production are responsible for these colour variants. This gene locus is called C-locus. The wild type allele C is dominant and causes full pigmentation, the Siamese cs allele is recessive and leads to the characteristic distribution of the dark colour on ears, mask, tail and legs when in the homozygous state. The Burmese pattern also follows a recessive inheritance and leads to the coat colour Burmese brown in the homozygous state, with varying degrees of black and dark brown.

How can the different genotypes for the colours chocolate and cinnamon and the Siamese and Burmese patterns be identified ?

Recently, the mutations leading to the different coat colours have been found in the USA, thus permitting the development of a genetic test for each of the colours. After validating these tests in collaboration with several german veterinarians and cat breeders, Laboklin can now offer the tests to all interested breeders. For the coat colour chocolate, Laboklin tests the four most important gene loci, therefore ensuring a very reliable test. For the coat colour cinnamon as well as the Siamese and Burmese coat patterns, only one mutation has been published to be responsible for the corresponding colour.

How does the genetic test work and how safe is it?

Firstly, the DNA which is the genetic information of an animal is isolated from a blood or a cheek swab sample. Then the genes of interest are amplified a million-fold by PCR (polymerase chain reaction) to facilitate the following analysis. The analysis is automatically performed by a genetic analyzer and reveals the gene sequence of the region of interest.

Therefore, the mutations leading to the different coat colours can be seen directly and heterozygous carriers of these mutations can also be identified. Since the test is done mainly automatically, laboratory errors can be widely excluded.

Interpretation of the test results

The test results will be submitted separately for each coat colour, so that the genotype for each corresponding gene locus will be given.