CLAD

Canine Leukocyte Adhesion Deficiency

Introduction

DESCRIPTION
Canine Leukocyte Adhesion Deficiency (CLAD) is a very nasty inherited abnormality of the immune system, which makes white blood cells unable to fight off infections. The condition is characterised by recurrent infections, reduced wound healing and reduced leukocyte (white blood cell) anti-bacterial activity. Puppies with CLAD usually die early on from multiple and repeated infections of the skin and bone marrow, even when treated with massive doses of antibiotics.

It is unusual for CLAD affected dogs to live to maturity.

CLAD is a deadly immunodeficiency disease with an easy-to-trace manner of being passed down from parents to litters, known as an autosomal recessive mode of inheritance.

A mutated gene has been identified as being responsible for CLAD, and a DNA-based test is available.

It is of advantage to breeders to be able to identify heterozygotes, - (CLAD carriers which may show no symptoms having inherited one good gene and one bad gene)- in order to prevent the birth of affected pups, and the continuation and spreading of the disease. However, the disease’s symptoms are often confused with those of non-specific infections, making it difficult to diagnose and to assess how much of the mutant allele (gene) has penetrated the local breeding population.

CLAD has often been misinterpreted as herpes, puppy fading syndrome and even leukaemia.

So far, CLAD has been found only in Irish Setters, and Irish Red and White Setters. Research on the disease was carried out in England and Scandinavia, where the carrier rate has been recorded as close to 12%. However, CLAD was first identified clinically in the United States. Reliable figures on the carrier rate in the USA are not available to me.

INHERITANCE
Canine Leukocyte Adhesion Deficiency 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 - typically show no symptoms but can pass the defective gene on to their offspring. Carrier–to–carrier matings should be avoided and discouraged, 25% affected, 50% carriers and 25% clear when you cross two carriers.

DNA
Using a DNA test, the gene associated with Canine Leukocyte Adhesion Deficiency in Irish Setters, and Irish Red and White Setters, can be targeted to determine whether the tested dog is affected, clear of the disease, or is a carrier of the mutated gene. This test gives breeders the information needed to prevent CLAD from occurring within their lines.

Understanding DNA test results:

CONCLUSION

The disease is such that there can be no jusitification for breeding from CLAD affected animals, under any circumstances. All breeding stock should be DNA tested before being bred from, and such results should be freely available to the public domain.

Responsible breeders shall happily show the DNA based CLAD test results to potential puppy homes, knowing that they are doing right by their breeding programmes, and preventing heavy Veterinary expenses and heartache for the new puppy owners. Some Canine Bodies are able to print the test results directly onto the pedigree certificates of the puppy’s parents, making it easy to see what the situation is at a glance. All DNA testing bodies offer written test results.

The progeny of carrier or clear matings should be permanently identified by microchip or tattoo, registered with the relevant Canine Body or Kennel Club, and such registrations endorsed accordingly.

 A Setter’s CLAD status should not affect it’s eligibility for entry into Kennel Union licensed events.

The Setter’s CLAD status may be directly reflected by being printed onto the Advanced Registration Certificate issued, which you may ask your breeder to show you.

For more information, or to contact the DNA-based testing bodies directly:

Thank you to Vanessa Mason (click here to see her website) for use of this information.