L-2 Hydroxyglutaric Aciduria (L-2HGA) Testing Guide for Dogs

L-2 hydroxyglutaric aciduria, abbreviated as L-2HGA, is a genetic neurometabolic condition that affects the nervous system of certain dog breeds. It causes a harmful build-up of L-2-hydroxyglutaric acid in body tissues, leading to progressive neurological symptoms. Responsible breeding and early Staffordshire bull terrier puppies testing can help reduce the incidence of this disorder.

Understanding L-2 Hydroxyglutaric Aciduria in Dogs

L-2HGA is an autosomal recessive inherited disease caused by mutations in the L2HGDH gene, which prevents the normal breakdown of L-2-hydroxyglutaric acid. This acid accumulates in the dog's urine, blood plasma, and cerebrospinal fluid, especially damaging areas of the brain such as the cerebellum that coordinate movement.

The condition usually appears between 4 months and 3 years of age, though some dogs may show symptoms shortly after birth. Clinical signs vary but commonly include a wobbly gait (ataxia), poor coordination, tremors, muscle stiffness, seizures, and behavioural changes. The severity varies greatly; some dogs live into their teens with supportive care, while others are euthanised young due to rapid progression.

Which Dogs Are Most At Risk?

In the UK, L-2HGA has a notable presence in three breeds: Staffordshire bull terriers, Yorkshire terrier puppies, and Biewer terriers. Due to the genetic basis of the disease, testing breeding stock is essential to prevent passing the mutation to future generations.

How L-2HGA Is Inherited

Being an autosomal recessive condition, each dog’s genetic status falls into three categories:

• Clear (homozygous normal): No copies of the mutant gene; not affected and cannot pass the mutation.
• Carrier (heterozygous): One copy of the mutant gene; generally healthy but can pass the mutation to offspring.
• Affected (homozygous mutant): Two copies of the mutant gene; will develop L-2HGA and pass it to all pups.

The outcome of breeding pairs:

• Two clear dogs produce only clear puppies.
• Two affected dogs produce only affected puppies.
• A clear dog bred with an affected dog produces only carriers.
• A carrier bred with an affected dog produces 50% affected and 50% carrier puppies.
• Two carrier dogs produce litters that are 25% clear, 50% carriers, and 25% affected.

Testing for L-2HGA

Genetic DNA testing is the gold standard for detecting L-2HGA in dogs. The test is typically done via a cheek swab sample taken by your vet, sent to an approved laboratory. Results classify dogs as clear, carrier, or affected with nearly 100% accuracy due to duplicate testing.

The Kennel Club and British Veterinary Association recommend testing all breeding dogs of at-risk breeds to avoid breeding affected puppies and help eradicate the condition from bloodlines. Testing is available from UK labs such as Laboklin and others specialising in veterinary genetics.

In symptomatic dogs, clinical diagnosis can be supported by MRI scans showing characteristic changes in brain regions and biochemical assays measuring elevated L-2-hydroxyglutaric acid in urine and cerebrospinal fluid.

Responsible Breeding and Management

Breeders are encouraged to test prospective breeding dogs early in life and plan matings based on clear or carrier status to prevent affected litters. Since there is no cure for L-2HGA, prevention is the key approach to reducing suffering.

For owners of affected dogs, supportive care from your vet is essential, and working with a veterinary neurologist may be recommended for managing seizures and other neurological symptoms.

Summary

L-2 Hydroxyglutaric Aciduria is a serious hereditary disorder in several UK dog breeds causing neurological symptoms with no cure. Genetic testing is a reliable tool to identify carriers and affected dogs early, informing responsible breeding choices and improving canine welfare.

By having your Staffordshire bull terrier or Yorkshire terrier tested, you contribute to reducing the impact of this condition and promote healthier generations of dogs.