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Feline Leukocyte Adhesion Deficiency (CD18, FLAD)
| Acronym: | FLAD |
| Gene: | ITGB2 |
| Mutation: | c.46_58+11del |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
| Method: |
Genetics and characteristics
Leukocyte Adhesion Deficiency (LAD) also known as CD18 Deficiency is a genetic primary immunodeficiency described in people, cats, cattle, dogs, and mice. The type described in cats, Feline Leukocyte Adhesion Deficiency or FLAD, is caused by a mutation in the ITGB2 gene. ITGB2 encodes integrin beta-2 subunit and its malfunction causes deficiency of the molecules normally expressed on all leukocyte surface membranes that play an important role in mediating strong neutrophil adhesion and serving as co-receptors for activation of T-lymphocyte proliferation. Affected cats usually show severe neutrophilia or producing a large number of this type of white blood cell, but they are unable to egress from blood vessels, migrate to the site of infection, and mount an effective innate immune response. That is why affected cats usually have problems with teeth loss, recurrent overwhelming bacterial infections poorly responsive to antibiotic therapy, and impaired pus formation and wound healing.
This primary immunodeficiency in cats is inherited as an autosomal recessive trait meaning both mutated ITGB2 genes are required for the disease to develop. Cats with only one copy of the mutated gene will not develop the disease but may act as carriers and pass the mutation to their offspring. Early genetic testing can help identify cats that carry the gene with the specific mutation and prevent their further breeding by proper selection of mating pairs.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Bauer, T. R., Jr, Pratt, S. M., Palena, C. M., Raj, K., Giger, U. (2017). Feline leukocyte adhesion (CD18) deficiency caused by a deletion in the integrin β2 (ITGB2) gene. Veterinary clinical pathology, 46(3), 391–400. https://doi.org/10.1111/vcp.12526