Clinical Signs in 166 Beagles with Different Genotypes of Lafora.

Lafora disease (LD) is a genetic disease affecting beagles, resulting in seizures in combination with other signs. The aim of this study was to describe the clinical signs of LD in beagles with different NHLRC1 genotypes. One hundred and sixty-six beagles were tested for an NHLRC1 gene defect: L/L (n = 67), N/L (n = 32), N/N (n = 67). Owners were asked to participate in a survey about the clinical signs of LD in their dogs. These were recorded for the three possible genotypes in the two age groups, <6 years and ≥6 years. In all genotypes, nearly all the signs of LD were described. In the age group ≥ 6 years, however, they were significantly more frequent in beagles with the L/L genotype. If the following three clinical signs occur together in a beagle ≥ 6 years-jerking of the head, photosensitivity and forgetting things he/she used to be able to do-98.2% of these dogs are correctly assigned to the L/L genotype. If one or two of these signs are missing, the correct classification decreases to 92.1% and 13.2%, respectively. Only the combination of certain signs truly indicates the L/L genotype. Yet, for many dogs, only genetic testing will provide confirmation of the disease.

A retrospective case series of clinical signs in 28 Beagles with Lafora disease.

BACKGROUND: Clinical signs and their progression in Beagles with Lafora disease are poorly described. OBJECTIVES: To describe clinical signs in Beagles with Lafora disease. ANIMALS: Twenty-eight Beagles with Lafora disease confirmed by genetic testing or histopathology. METHODS: Retrospective multicenter case series. Data regarding signalment, clinical signs, diagnostic tests and treatment were retrieved from hospital data files. A questionnaire was sent to owners asking about neurological deficits, changes in cognitive functions, behavioral changes, response to treatment and survival time. RESULTS: Onset of clinical signs was 8.3 years (mean; range, 6.3-13.3). All dogs had myoclonic episodes as an initial clinical sign with tonic-clonic seizures in n = 11/28 (39%) and n = 12/28 (43%) later developing tonic-clonic seizures. Deficits of coordination (n = 21/25; 84%), impaired vision (n = 15/26; 58%), and impaired hearing (n = 13/26; 50%) developed later. Mental decline was observed as loss of house training (urination; n = 8/25; 32%), difficulties performing learned tasks (n = 9/25; 36%), and difficulties learning new tasks (n = 7/23; 30%). Common behavioral changes were: increased photosensitivity (n = 20/26; 77%), staring into space (n = 16/25; 64%), reduced stress resistance (n = 15/26; 58%), increased noise sensitivity (n = 14/26; 54%), and separation anxiety (n = 11/25; 44%). Twenty-one dogs were alive (median age 11.9 years; range, 9.8-18.6), and 7 dogs were dead (mean age 12.1 years; SD: 1.3; range, 10.5-12.6) at time of writing. CONCLUSIONS AND CLINICAL IMPORTANCE: Lafora disease in Beagles causes significant behavioral changes, and mental decline as well as neurological deficits in addition to myoclonic episodes and generalized tonic-clonic seizures. Nevertheless, a relatively normal life span can be expected.

NHLRC1 homozygous dodecamer expansion in a Newfoundland dog with Lafora disease.

Lafora disease is a genetic disease caused, in humans, by mutations in EPM2A and NHLRC1 genes, resulting in accumulation of polyglucosan bodies within neurons. Affected subjects present progressive neurological signs characterised primarily by myoclonic epilepsy. In dogs, Lafora disease has been described mainly in miniature wire-haired Dachshunds, where a dodecamer expansion in NHLRC1 gene has been identified. The same mutation has then been detected in the Basset Hound, Beagle, Chihuahua and Pembroke Welsh Corgi breeds. This is the first case of a Newfoundland dog with myoclonic epilepsy diagnosed with Lafora disease based on confirmed dodecamer expansion in the NHLRC1 gene. Lafora disease is being progressively recognised in different unrelated breeds suggesting a wider distribution in the canine population than previously thought.

[Lafora disease in a Beagle - diagnosis and therapy]. / Lafora-Erkrankung bei einem Beagle ­ Diagnose und Therapie.

Lafora disease is an autosomal recessive lysosomal storage disorder leading to an accumulation of toxic glycogen bodies into the cells of the central nervous system and other tissues. In the progressive form of myoclonic epilepsy, clinical signs typically start around 7 years of age. Causal therapy is impossible, however, in the early stages the symptoms may at least be alleviated by modern antiepileptic drugs. In the case reported here, an approximately 7-year-old Beagle presented with daytime-dependent fasciculations, focal and generalized myoclonus ranging up to a brief tonic-clonic seizure. The signs could be triggered and augmented by stress, sounds and light. Histologic examination was performed on biopsy samples of skin, liver, muscle and nervous tissue to test for the clinical diagnosis of Lafora disease. Sarcoplasmic PAS-positive pla®ue deposits typical of Lafora bodies were detected in the muscle biopsies but not in any of the other specimens. Initial treatment with phenobarbital and imepitoin was unsuccessful. However, treatment with levetiracetam significantly alleviated the clinical signs. At time of writing this publication, 2 years following the diagnosis, the now 9-year-old dog shows occasional, stress-related increase in fokal myoclonic seizures. Episodes of collapse or tonic-clonic seizures did not occur to any further extent.

Brain proton magnetic resonance spectroscopy findings in a Beagle dog with genetically confirmed Lafora disease.

Cortical atrophy has been identified using magnetic resonance imaging (MRI) in humans and dogs with Lafora disease (LD). In humans, proton magnetic resonance spectroscopy (1HMRS) of the brain indicates decreased N-acetyl-aspartate (NAA) relative to other brain metabolites. Brain 1HMRS findings in dogs with LD are lacking. A 6-year-old female Beagle was presented with a history of a single generalized tonic-clonic seizure and episodic reflex myoclonus. Clinical, hematological, and neurological examination findings and 3-Tesla MRI of the brain were unremarkable. Brain 1HMRS with voxel positioning in the thalamus was performed in the affected Beagle. It identified decreased amounts of NAA, glutamate-glutamine complex, and increased total choline and phosphoethanolamine relative to water and total creatine compared with the reference range in healthy control Beagles. A subsequent genetic test confirmed LD. Abnormalities in 1HMRS despite lack of changes with conventional MRI were identified in a dog with LD.

Accumulation of Laforin and Other Related Proteins in Canine Lafora Disease With EPM2B Repeat Expansion.

Canine Lafora disease (LD) is an autosomal recessive genetic disorder causing nonfatal structural epilepsy, mainly affecting miniature wirehaired dachshunds. Repeat expansion in the EPM2B gene causes a functional impairment of the ubiquitin ligase malin which regulates glycogen metabolism. Abnormally structured glycogen accumulates and develop polyglucosan bodies predominantly in the central nervous system. The authors performed a comprehensive clinical, genetic, and pathological study of 4 LD cases affecting miniature wirehaired dachshund dogs with EPM2B repeat expansions, with systemic distribution of polyglucosan bodies and accumulation of laforin and other functionally associated proteins in the polyglucosan bodies. Myoclonic seizures first appeared at 7-9 years of age, and the dogs died at 14-16 years of age. Immunohistochemistry for calbindin revealed that the polyglucosan bodies were located in the cell bodies and dendritic processes of Purkinje cells. Polyglucosan bodies were also positive for laforin, hsp70, α/ß-synuclein, ubiquitin, LC3, and p62. Laforin-positive polyglucosan bodies were located in neurofilament-positive neurons but not in GFAP-positive astrocytes. In nonneural tissues, periodic acid-Schiff (PAS)-positive polyglucosan bodies were observed in the heart, skeletal muscle, liver, apocrine sweat gland, and smooth muscle layer of the urinary bladder. In the skeletal muscle, polyglucosan bodies were observed only in type 1 fibers and not in type 2 fibers. The results indicate that although the repeat expansion of the EPM2B gene is specific to dogs, the immunohistochemical properties of polyglucosan body in canine LD are comparable to human LD. However, important phenotypic variations exist between the 2 species including the affected skeletal muscle fiber type.

Lafora disease in miniature Wirehaired Dachshunds.

Lafora disease (LD) is an autosomal recessive late onset, progressive myoclonic epilepsy with a high prevalence in the miniature Wirehaired Dachshund. The disease is due to a mutation in the Epm2b gene which results in intracellular accumulation of abnormal glycogen (Lafora bodies). Recent breed-wide testing suggests that the carrier plus affected rate may be as high as 20%. A characteristic feature of the disease is spontaneous and reflex myoclonus; however clinical signs and disease progression are not well described. A survey was submitted to owners of MWHD which were homozygous for Epm2b mutation (breed club testing program) or had late onset reflex myoclonus and clinical diagnosis of LD. There were 27 dogs (11 male; 16 female) for analysis after young mutation-positive dogs that had yet to develop disease were excluded. Average age of onset of clinical signs was 6.94 years (3.5-12). The most common initial presenting sign was reflex and spontaneous myoclonus (77.8%). Other presenting signs included hypnic myoclonus (51.9%) and generalized seizures (40.7%). Less common presenting signs include focal seizures, "jaw smacking", "fly catching", "panic attacks", impaired vision, aggression and urinary incontinence. All these clinical signs may appear, and then increase in frequency and intensity over time. The myoclonus in particular becomes more severe and more refractory to treatment. Signs that developed later in the disease include dementia (51.9%), blindness (48.1%), aggression to people (25.9%) and dogs (33.3%), deafness (29.6%) and fecal (29.6%) and urinary (37.0%) incontinence as a result of loss of house training (disinhibited type behavior). Further prospective study is needed to further characterize the canine disease and to allow more specific therapeutic strategies and to tailor therapy as the disease progresses.

NHLRC1 repeat expansion in two beagles with Lafora disease.

Lafora disease is a fatal genetic disorder characterised by neurotoxic deposits of malformed insoluble glycogen. In humans it is caused by mutation in the EPM2A or NHLRC1 genes. There is a known mutation in miniature wirehaired dachshunds which has not been documented in other dog breeds, including beagles, in which the disease is relatively commonly reported. This case report describes the causative defect in two affected beagles, namely the same massive expansion as in miniature wirehaired dachshunds of a 12-nucleotide repeat sequence that is unique to the canine NHLRC1 gene. This is the first mutation described in beagles with Lafora disease, and so far the only Lafora disease genetic variant in dogs.

Lafora's-like disease in a fennec fox (Vulpes zerda).

A 6-yr-old captive-born female fennec fox (Vulpes zerda) had a history of multiple seizures and was treated with diazepam and phenobarbital therapy. Despite medical treatment, the seizures continued. They were intermittent and progressive, resulting in neurologic deficits and death of the animal within 6 mo of onset of the clinical signs. At necropsy, the animal was in good nutritional condition, and no gross lesions were noted in the brain. Histologically, amphophilic to basophilic, periodic acid-Schiff (PAS) positive, diastase-resistant inclusions were present in the brain, heart, and liver. Ultrastructurally, the inclusions were variably electron dense, fibrillary to occasionally granular, and non-membrane bound. The clinical, histologic, and ultrastructural findings were consistent with Lafora's disease, which in humans is a rare, fatal, autosomal recessive hereditary neurometabolic disorder characterized by progressive myoclonic epilepsy. This is the first report of Lafora's-like disease in a fennec fox.

Characterisation of Lafora-like bodies and other polyglucosan bodies in two aged dogs with neurological disease.

Canine Lafora disease is a genetic disorder of carbohydrate metabolism characterised by neurological signs and accumulation of a type of polyglucosan body (PGB), the Lafora body (LB), in the brain and other organs. Normal canine ageing is associated with accumulation of PGBs in the brain, especially those corresponding to corpora amylacea (CA). In this study, two aged dogs that presented with progressive tremors, ataxia and paraplegia had abundant PGBs throughout the brain, mainly in the hypothalamus and molecular layer of the cerebellum. Hypothalamic and cerebellar PGBs from both cases had lower alcohol-resistant metachromasia than CA when stained with toluidine blue. Immunohistochemical studies of these PGBs against neurone-specific enolase (NSE), glial fibrillary acid protein (GFAP), 200 KDa neurofilaments, S-100, Tau, ubiquitin and heat shock proteins 25 and 70, showed some differences to CA.

Lafora disease as a cause of visually exacerbated myoclonic attacks in a dog.

An 8-year-old, castrated male, miniature wire-haired dachshund was presented with a 4-month history of intermittent facial twitching (myoclonus). The myoclonic episodes progressed over a 16-month period. Generalized seizure activity was infrequent. Clinical examination revealed visually stimulated myoclonus. Response to therapy with antiepileptic drugs was equivocal. Genetic testing identified the dog as being affected by Lafora disease.

Expanded repeat in canine epilepsy.

Epilepsy afflicts 1% of humans and 5% of dogs. We report a canine epilepsy mutation and evidence for the existence of repeat-expansion disease outside humans. A canid-specific unstable dodecamer repeat in the Epm2b (Nhlrc1) gene recurrently expands, causing a fatal epilepsy and contributing to the high incidence of canine epilepsy. Tracing the repeat origins revealed two successive events, starting 50 million years ago, unique to canid evolution. A genetic test, presented here, will allow carrier and presymptomatic diagnosis and disease eradication. Clinicopathologic characterization establishes affected animals as a model for Lafora disease, the most severe teenage-onset human epilepsy.

Progressive myoclonus epilepsy in a beagle.

A nine-year-old, neutered female beagle was presented with a history of progressive myoclonic jerks. Clinical signs included mental depression and paroxysmal jerks of the head and forelimbs, apparently elicited by changes in light, noise or movements. Electroencephalographic findings were in accordance with myoclonus epilepsy. Postmortem histopathological findings included multiple periodic acid-Schiff-positive inclusion bodies throughout the central nervous system, but especially in the cerebellum, confirming the suspected diagnosis of Lafora's disease.