Canine leucocyte 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. A few years later it was also identified in the UK in Irish Red and White Setters  descended from dogs imported from Ireland.

 Affected puppies are often, but not always, comparatively small and slow to develop. They show infections from a very early age - umbilical infection at birth, tonsillitis, sores on the body and accidental wounds or scratches that will not heal. Between 8 and 14 weeks there can be inflammation of the gums, which become red and swollen. Most puppies get swollen joints with the bone beside the joint thickening and affecting movement, making the dog unsteady until finally the animal is unable to stand up. Affected puppies seem to be sore all over their body. The lower jaw becomes wider, due to bone deposits and they have difficulty in opening their mouths. Their temperature is raised and they seem to sleep more than usual. Puppies will not necessarily have all of these symptoms at one time.

INHERITANCE
CLAD in Irish Setters and Irish Red and White Setters shows an autosomal recessive mode of inheritance; therefore two copies of the defective gene, one inherited from each parent, have to be present for a dog to be affected by the disease. Dogs with one copy of the defective gene and one copy of the normal gene - called carriers - show no symptoms but can pass the defective gene onto their offspring.

DNA TEST
Traditionally, no one test has been used to conclusively diagnose CLAD 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 CLAD in Irish Setters and IRWS  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.

Interpretation

Normal - Homozygous for normal gene, will never develop the disease, and if mated to another normal dog, the offspring will all be normal

 

Carrier - Carries one mutant gene, and will never develop the disease, but if mated to a normal dog, some of the offspring will be carriers. If mated to another carrier, some of the offspring will be affected

 

Affected - Homozygous for disease gene and will develop the disease