Lafora disease / progressive myoclonic epilepsy (NHLRC1-related) - Dog

What does this test analyse?

This genetic test analyses the NHLRC1 repeat expansion that causes Lafora disease in dogs. The condition is also known as progressive myoclonic epilepsy, myoclonus epilepsy of Lafora and a polyglucosan storage disease. The tested change is an expansion of a 12-nucleotide repeat in NHLRC1, a gene involved in normal glycogen handling in nervous tissue.

What does this condition mean?

Lafora disease is an inherited, late-onset and progressive neurological disorder. Affected dogs can develop myoclonic jerks, often triggered by flashing light, sound or movement near the head. As the disease progresses, seizures, ataxia, vision problems, cognitive decline and behavioural changes may occur. Because first signs often appear in adulthood, a dog may already have been used for breeding before the condition is recognised.

Inheritance and result

The condition is inherited as an autosomal recessive trait. Clear dogs do not carry the repeat expansion. Carriers have one normal and one expanded repeat and can pass the variant on. Dogs with two expanded repeats develop the genetic form of Lafora disease.

Practical value of this test

• Helps breeders identify hidden carriers before mating decisions are made.
• Supports breeding choices in breeds where Lafora can appear in adulthood.
• Gives owners clarity when myoclonus, seizures or family risk are relevant.
• Provides genetic documentation for breeding animals, offspring and lines where this repeat expansion matters.

Why test early?

Lafora is particularly challenging for breeders because the disease usually becomes visible later in life. A young dog may appear clinically normal while carrying a repeat expansion or even having the affected genotype. Testing before breeding clarifies which combinations are safe and which combinations create a real risk of affected offspring. The test also helps place neurological signs in older dogs into the correct genetic context more quickly.