L-2 Hydroxyglutaric Aciduria (L-2HGA) testing for dogs

L-2 hydroxyglutaric aciduria, known as L-2HGA for short, is a metabolic disorder that affects the nervous system of dogs with the disorder, and is a hereditary health condition that can be passed on from generation to generation through the breed line.

The condition is known to be present within a few common UK dog breeds, and cannot be passed or transmitted from dog to dog other than by means of heredity.

L-2HGA affects the cerebellum, the part of the brain that coordinates movement. This in turn causes dogs affected with the condition to show a lack of muscle coordination, poor balance and general clumsiness.

In order to try to reduce the incidences of the condition presenting in further generations of dog, breeds that are known to be at risk of the condition due to its relatively wide distribution through breed lines should be tested for the condition prior to breeding.

The Kennel Club in association with the British Veterinary association, oversees a DNA testing scheme for the condition, which breeders of dogs that can be affected by the condition are strongly advised to take part in in order to ensure that they breed only healthy dogs.

In this article, we will look at L-2 hydroxyglutaric aciduria in dogs in more detail, including how the heredity of the condition works, how it can be tested for, and what sort of dogs can be affected by the condition. Read on to learn more.

More about L-2 hydroxyglutaric aciduria in dogs

L-2 hydroxyglutaric aciduria is a hereditary neuro-metabolic disorder, which is caused by L-2 hydroxyglutaric acid failing to break down as it should do in the body, leading to raised levels of this acid being found in the dog’s urine, cerebrospinal fluid and blood plasma.

The same condition can be found in people too, and in dogs it can lead to a variety of different signs and symptoms, not all of which will be present in every case.

Generally, the condition begins to present with symptoms when the dog is aged between six months and twelve months old, although it can take up to three years to become apparent, and in rare cases can be diagnosed shortly after the puppy is born.

Exactly how badly the condition affects dogs can vary from case to case too, with some dogs living into their teens with a good quality of life, while some dogs will die before they reach a year old, or be euthanized because of the impact that it has upon them.

Dogs affected with the condition will display fit-like seizures, a loss of coordination and appear to un-learn skills and commands that they previously exhibited reliably.

It can also lead to hind leg cramps and shaking, and other muscular and nerve-related symptoms.

What sort of dogs can be affected by the condition?

L-2 hydroxyglutaric aciduria is found at incidence rates high enough to warrant pre-breeding testing in UK dog populations across three breeds; the Staffordshire bull terrier, Yorkshire terrier and Biewer terrier.

Dogs of these breeds that are intended to be used for breeding should be tested for the markers of the condition before any planned mating goes ahead, to ensure that the condition is not passed on through the breed line.

How does the heredity of the condition work?

L-2 hydroxyglutaric aciduria is an autosomal recessive condition, which means that a dog may have one of three statuses where the condition is concerned-clear, affected or carrier. Carriers will not be affected by the condition themselves, but can still pass the markers for the condition on to their offspring, and whether or not their offspring will in turn be clear, carrier or affected depends on the status of the two parent dogs combined.

• Two clear dogs will have clear puppies.
• Two affected dogs will have affected puppies.
• A clear dog mated with an affected dog will produce a litter of carriers.
• A carrier dog mated with an affected dog will produce a litter with 50:50 odds of being affected or carriers.
• If two carrier dogs are bred, their litter’s odds are 50% carrier, 25% clear, and 25% affected.

How to get your dog tested

If you own a dog of one of the three at-risk breeds, it is really important to have them tested for their status prior to breeding, and finding out the results for the other dog in the planned match too.

To test for the condition, you will need to ask your vet to take a DNA sample from your dog (usually in the form of a cheek swab) which is then sent off to an approved laboratory to test, and return the dog’s status. For information on labs in the UK that can perform the test, check out this list on The Kennel Club’s website.