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Lafora Disease

Lafora Disease (LD) is a progressive, genetic neurological disorder characterized by myoclonic epilepsy, primarily affecting older dogs.

Affected Genes: NLHRC1

Inheritance: Autosomal Recessive

Variant(canFam6):
chr35:16871421-16871422: insertion Variable 12-mer (GCGGGGGGCGGC) repeat expansion - wild type is 1-2 copies, disease is 14-26 copies

Breed: Basset Hound
Beagle
Brussels Griffon
Chihuahua
French Bulldog
Miniature Wirehaired Dachshund
Newfoundland
Newfypoo
Pembroke Welsh Corgi

General Information: Lafora Disease (LD) is a severe form of epilepsy that manifests as myoclonic seizures, which are quick, involuntary muscle jerks. This condition often appears in dogs later in life, typically beyond five years of age. It is characterized by episodes triggered by visual stimuli like flashing lights or sudden movements, alongside noises that provoke reflex jerks. As the disease progresses, dogs may also experience general or focal seizures, accompanied by visual impairment, loss of coordination, and dementia-like symptoms. This debilitating condition progressively worsens, leading to significant declines in quality of life, necessitating medical intervention due to severe neurological impairments.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog Unlikely Affected

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing for Lafora Disease (LD) focuses on identifying mutations in the NHLRC1 gene, which are critical for determining carriers and managing breeding practices. This condition is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene, one from each parent, to develop the disease. Dogs that carry only one copy of the gene do not typically show symptoms but can pass the mutation to their offspring. Testing is vital for breeders to avoid mating two carriers, which would give each offspring a 25% chance of inheriting the disease. Breeding practices should be adjusted based on genetic test results to prevent the propagation of this disorder. Dogs confirmed not to carry the mutation will not transmit this specific genetic condition to any offspring, although it's crucial to note that a clear test for NHLRC1 does not rule out other genetic disorders or forms of PRA.

References:
Ahonen S, Seath I, Rusbridge C, Holt S, Key G, Wang T, Wang P, Minassian BA. Correction to: Nationwide genetic testing towards eliminating Lafora disease from Miniature Wirehaired Dachshunds in the United Kingdom. Canine Med Genet. 2021 Dec 27;8(1):14. Erratum for: Canine Genet Epidemiol. 2018 5:2.

Lohi H, Young EJ, Fitzmaurice SN, Rusbridge C, Chan EM, Vervoort M, Turnbull J, Zhao X, Ianzano L, Paterson AD, Sutter NB, Ostrander EA, Andre C, Shelton D, Ackerley CA, Scherer SW, Minassian BA. Expanded Repeat in Canine Epilepsy. Science. 2005 307(5706):81.

Sainsbury R. DNA screening for Lafora’s disease in miniature wire-haired dachshunds. Vet Rec. 2014 Dec 6;175(22):568.

Swain L, Key G, Tauro A, Ahonen S, Wang P, Ackerley C, Minassian BA, Rusbridge C. Lafora disease in miniature Wirehaired Dachshunds. PLoS One 2017 12(8):e0182024.

von Klopmann T, Ahonen S, Espadas-Santiuste I, Matiasek K, Sanchez-Masian D, Rupp S, Vandenberghe H, Rose J, Wang T, Wang P, Minassian BA, Rusbridge C. Canine Lafora Disease: An Unstable Repeat Expansion Disorder. Life (Basel). 2021 11(7):689.

Webb AA, McMillan C, Cullen CL, Boston SE, Turnbull J, Minassian BA. Lafora disease as a cause of visually exacerbated myoclonic attacks in a dog. Can Vet J. 2009 50(9):963-967.