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Canine Mendelian disease record

Benign Familial Juvenile Epilepsy (Discovered in the Lagotto Romagnolo; BFJE)

Benign Familial Juvenile Epilepsy (Discovered in the Lagotto Romagnolo; BFJE). Autosomal recessive. Observed in 1 of 266 breeds tested in the Sniff Atlas, with measured carrier frequencies drawn from 242,664 dogs (Donner 2023). Per-dog phenotype outcome depends on penetrance, modifiers, and environment; the carrier frequencies below describe variant prevalence, not disease incidence.

OMIA identifier
OMIA:001596-9615
Autosomal recessive
Source dataset
Sniff Atlas v1.0.1 / DOI
About this disease

From OMIA's curated record

Documented in OMIA (Online Mendelian Inheritance in Animals). This describes the disease as recorded in the published literature, not a prediction for any individual dog. As of 2026-06-03.

Summary

Renamed from 'Epilepsy, benign familial juvenile' to 'Epilepsy, benign familial juvenile, LGI2-related' [11/06/2024]

Clinical features

BFJE is characterised by juvenile-onset seizures beginning at five to nine weeks of age and typically spontaneously remit by thirteen weeks of age (Jokinen et al., 2007). Affected puppies exhibit generalised tremor, ataxia and stiffness during seizures and severe cases show neurological signs such as ataxia and hypermetria between epileptic episodes (Jokinen et al., 2007). Seizures can occur at any time of the day and the puppy may or may not be conscious during the episode (Jokinen et al., 2007). Following remission, BFJE-affected puppies often show behavioural abnormalities in adulthood, including increased inattention and excitability (Jokinen et al., 2015). On rare occasions, the patient may experience seizures years after remission, or develop progressive neurological disorders that eventually require euthanasia (Jokinen et al., 2015). BFJE puppies show epileptiform activity on electroencephalogram, both during and in between epileptic episodes. IT thanks DVM student Tina Gong, who provided the basis of this contribution in May 2023.

Molecular genetics

By sequencing the most likely of 9 positional candidate genes (see Mapping section), Seppälä et al. (2011), part of the LUPA consortium, discovered that this type of epilepsy in the Lagotto romagnolo breed is due to a nonsense mutation (c.1552A>T (p.K518X)) in the gene for LGI2. Noting that mutations in this gene have not yet been reported to be causative of epilepsy in humans, but that mutations in a "sister" gene, LGI1, result in lateral temporal lobe epilepsy in humans, the authors go to considerable lengths to describe how this discovery in dogs may well inform future studies of the genetic basis of epilepsy in humans.

Pathology

Affected dogs have a relatively small cerebellum and intracytoplasmic inclusion bodies in cerebellar Purkinje cells (Jokinen et al., 2007). IT thanks DVM student Tina Gong, who provided the basis of this contribution in May 2023.

Inheritance

Seppälä et al. (2011): "BFJE is transmitted in imperfect Mendelian fashion. In the vast majority of cases, 93%, homozygous mutation is required for the disease to manifest. In a minority, 7%, heterozygosity suffices. Conversely, 1.8% of dogs may be resistant to seizing despite homozygous mutation. Finally, we found no dog with homozygous wt genotype at Lgi2 c.1552 that has BFJE."

Human analog

OMIA links this condition to the human gene record in OMIM (Mendelian Inheritance in Man), the place to read across to the deeper human literature for the same biology.

Gene · OMIM 608301

Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:001596-9615, doi:10.25910/2AMR-PV70 (CC-BY 4.0).

The evidence

Published references

The peer-reviewed papers behind this disease, curated by OMIA. Starred entries are OMIA-designated landmark papers. Showing 6 of 9.

  4. Canine versus human epilepsy: are we up to date? · J Small Anim Pract · 2016 · PMID 26931499
  6. Inherited epilepsy in dogs. · Top Companion Anim Med · 2013 · PMID 24070682

References curated by OMIA (Nicholas, Tammen & the Sydney Informatics Hub), doi:10.25910/2AMR-PV70 (CC-BY 4.0). Full list at the OMIA entry.

Predict a litter

Set each parent's status for Benign Familial Juvenile Epilepsy (Discovered in the Lagotto Romagnolo; BFJE) and see the odds for their puppies. Single recessive variant, exact Mendelian math.

Parent A
Parent B
NNClear
NmCarrier
NmCarrier
mmAffected
Clear25%
Carrier50%
Affected25%

These are the genetic odds for one known variant, not a promise: a real litter varies around them, and penetrance or other genes can change whether the condition ever appears. Use it to avoid pairing two carriers and to keep a line healthy, not to engineer a dog. Inheritance mode per OMIA.
Your breed

See what Benign Familial Juvenile Epilepsy (Discovered in the Lagotto Romagnolo; BFJE) looks like in your dog's breed.
Carrier frequency by breed

Top 1 well-sampled breeds (n ≥ 50)

Maximum per breed across variants in the Donner 2023 cohort, with . The list below is split into well-sampled breeds (n ≥ 50 tested) and small-sample breeds (n < 50, where the Wilson CI typically spans more than 20 percentage points and frequencies should not be compared directly to the well-sampled entries). Frequencies are population-level, not per-litter or per-line.

0%10%20%
Lagotto Romagnolo12.7% · n 623
n = 623 dogs · Donner et al. 2023 carrier-screening cohort · Sniff Atlas
Each bar is one well-sampled breed; the whisker is its Wilson 95% CI, and fainter bars have wider intervals. Frequencies are population-level, not per-litter. Carrier status for Benign Familial Juvenile Epilepsy (Discovered in the Lagotto Romagnolo; BFJE) is measured; phenotype outcome depends on penetrance and modifiers.
▸ Full table with Wilson 95% confidence intervals
Breed Carrier frequency n tested
Lagotto Romagnolo 12.7% 623

265 additional breeds in the Donner 2023 cohort were tested but showed no carriers.

Scope of this record

Scope

This record carries the breed-level carrier frequencies from the Donner 2023 cohort. Penetrance data (the fraction of at-risk dogs that develop the phenotype) is not yet quantified for this disease in the Sniff Atlas v1.0.1. The OMIA entry is the authoritative reference for the clinical phenotype, inheritance pattern, and gene assignment.

Predicted disease relevance at the per-dog level is UNPROVEN. The carrier frequency is measured; phenotype outcome depends on penetrance, environment, and modifier loci. Consult a veterinarian for clinical interpretation.

How to cite this record

Citations

If you use this record in published work, cite the Sniff Atlas (the published dataset that carries the breed-level carrier frequencies) and the upstream sources:

  • Sniff Atlas v1.0.1 for the per-breed carrier frequencies:

    Gehring, M. (2026). Sniff Atlas v1.0.1. Zenodo. https://doi.org/10.5281/zenodo.20566358. CC-BY 4.0.

  • OMIA for the disease definition, inheritance, and gene assignment:

    Nicholas, F. W., & Tammen, I. (2024). OMIA. Sydney Informatics Hub, The University of Sydney. https://doi.org/10.25910/2AMR-PV70. Entry: OMIA:001596-9615.

  • Donner et al. 2023 for the breed × variant carrier-frequency cohort:

    Donner, J., Freyer, J., Davison, S., Anderson, H., Blades, M., Honkanen, L., et al. (2023). Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics, 19(2), e1010651. https://doi.org/10.1371/journal.pgen.1010651.

Full citation formats (BibTeX, RIS, CITATION.cff) at sniff.world/cite.

Related

Related

Last updated
Sources: Sniff Atlas v1.0.1 · OMIA OMIA:001596-9615 · Donner et al. 2023