DNA test – XLHN (X-linked hereditary nephritis)

The X-linked nephritis DNA test can be used by breeders and owners to screen their dogs to see if they carry the gene variant linked to this health condition.

Details about the disease

Hereditary nephritis is an inherited condition that causes certain parts of a dog’s kidneys to become inflamed and stop working correctly. In males, and some females, this progresses to kidney failure and death.

Clinical signs

Affected male puppies usually develop signs before they are three months old. These signs may include drinking and weeing excessively, being sick, being off their food, losing weight or they may often seem tired. Affected male puppies may also have a slower growth rate. Veterinary investigations may discover anaemia, poor kidney function and protein or blood in their urine. Affected males die young, usually before 15 months old.

Affected females may lose weight and show signs of protein in their urine before they turn three months old, but they seem to be affected less severely than males. Seventy per cent of affected females develop kidney disease within five years of being born and 38 per cent develop life threatening kidney failure.

How is it inherited?

The disease is described as X-linked, which means that the faulty gene that causes this type of nephritis is found on the X-chromosome. The X-chromosome helps to determine a dog’s sex.

Male dogs only have one X-chromosome, which they always inherit from their mother, while females have two X-chromosomes, which they inherit from both their mother and father.

In females, the disease acts as an incomplete dominant trait, i.e., if a female only has one copy of the faulty gene and one healthy copy of the gene, her health will be affected, but not as severely as if she had two copies of the gene.

In males, because they only have a single copy of the X chromosome, the condition is dominant and they are either healthy (they only have a healthy copy of the gene), or severely affected (they only have the faulty copy of a gene).

Which laboratories do we record and publish the results from?

To find out which laboratories The Kennel Club is able to record results from, and which laboratories will send results directly to The Kennel Club, please refer to our website.

Please be aware, The Kennel Club has a set of criteria that we request DNA testing laboratories to meet to enable us to record their results, helping to maintain and protect the integrity of results that appear on a dog’s record. We strongly advise that customers ensure their chosen laboratory is included on our list if they wish The Kennel Club to record and publish the results. Results from laboratories not included on this list will not be recorded.

Breeding advice

The decision you make when choosing which dogs to mate must be informed and carefully planned.

If the health status of both sire and dam are known, the likely health status of any puppies produced can be predicted.

Please use the following table to note the outcome of mating a male and female with a known hereditary status:

  Clear male Single affected male
Clear female All puppies will be clear. All male puppies will be clear.

All female puppies will be single affected.
Single affected female Each male puppy will have 50% chance of being single affected.

Each female puppy will have 50% chance of being single affected.		 Each male puppy will have a 50% chance of being single affected.

Each female puppy will be affected, but they will have a 50% risk of being single affected and a 50% risk of being double affected.
Double affected female All male puppies will be single affected.

Each female puppy will be single affected.		 All male puppies will be single affected.

All female puppies will be double affected.
Breeding advice: If your dog is clear
Clear dogs should only be mated to other clear dogs. All other matings may produce affected puppies and so should not be carried out.
Breeding advice: If your dog is affected (either single or double)

Your dog should not be bred from. Mating this dog could produce affected puppies. Producing affected puppies that may develop nephritis could have a serious impact on their health and welfare. A mating which may produce affected puppies should never knowingly be carried out. If this mating accidentally occurs, it is important to test all of the puppies before they are bred from or are passed on to new homes. Veterinary advice should be sought as to the clinical management of any affected puppies.

Are clear dogs 100% clear?

Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease.

Making balanced breeding decisions

As well as considering the implications of a dog’s DNA test results, there are other equally important factors to consider when deciding whether two dogs should be mated together, such as temperament, genetic diversity, conformation, other available health test results, the general health of the dogs etc. Your breeding decisions should always be well balanced and take into consideration the qualities and compatibility of both the sire and dam that you are considering.

How to find out if a potential mate has been DNA tested

The health test results finder allows you to find the results of DNA tests carried out as part of our official DNA testing schemes for any dog on The Kennel Club’s Breed Register.