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Canine Leukocyte Adhesion Deficiency (CLAD) is an inherited abnormality of the immune system where the white blood cells are unable to fight infection. This disease was first identified in 1975 in Irish Setters. Several animals displaying various forms of recurrent infectious and immunological complications were found to have an aberrant expression of the CD18 molecule. The identification of the gene mutation responsible for the disease in Irish Setters was ascertained in mutational analysis of CD18 in Irish Setter CLAD pedigrees. From this, a single missense mutation was identified which showed complete association with CLAD in Irish Setters. This mutation is thought to be responsible for incomplete disulphide bonding within the ?-integrin protein, causing defects in its function and hence impaired immune function.
DNA Test
Traditionally, no one test has been used to conclusively diagnose Canine Leukocyte Adhesion Deficiency in Irish Setters. A technique known as flow cytometry has been used in the past with some success but can yield false negatives and requires specialized equipment. Fortunately, recent advances in molecular diagnostics have produced new methods that are more rapid, accurate, and economical than conventional techniques. Using a DNA test, the gene associated with Canine Leukocyte Adhesion Deficiency in Irish Setters can be targeted to determine whether the animal is affected, clear of the disease, or is a carrier of the mutated gene. This test provides definitive information on the genetic status of this disease in the animal, giving breeders the information needed to eradicate the CLAD from their lines. |
