Degenerative Disorders of the Peripheral Nerves and Neuromuscular Junction in Animals

Dancing Doberman disease and duck walking Doberman disease are neuromuscular diseases affecting Doberman Pinschers of either sex and ranging in age from approximately 6 months to 7 years. They are caused by a mutation in the AGRN gene, which encodes a glycoprotein, agrin, that is important in formation and maintenance of the neuromuscular junction. This mutation is associated with two phenotypes.

In the less severe phenotype, dancing Doberman disease, affected dogs intermittently flex the hip and stifle joints of one pelvic limb while standing. Within several months, most dogs alternately flex and extend both pelvic limbs, producing a characteristic movement that is described as dancelike. Affected dogs often prefer to sit rather than stand.

Dancing Doberman disease slowly progresses to mild paraparesis, decreased proprioception, and atrophy of the gastrocnemius muscles. The thoracic limbs are not affected. Histopathological changes associated with dancing Doberman disease are generally mild and nonspecific, consisting primarily of muscle fiber atrophy consistent with denervation.

The second, more severe phenotype is characterized by a crouched stance and "bunny-hopping" gait in the pelvic limbs (termed “duck walking”). Spinal reflexes in the pelvic limbs can be normal or decreased. Muscle biopsy results are consistent with mild denervation.

There is no specific treatment for these diseases, and clinical signs do not resolve. Treatment with albuterol was found to be associated with transient improvement in both dancing Doberman disease and duck walking Doberman disease (1). However, the disease does not usually result in severe disability and does not appear to be painful.

Distal denervating disease is a common polyneuropathy of dogs in the UK; few cases have been reported elsewhere. The cause is unknown but is believed to involve a degenerative process. Any age and breed of dog can be affected.

The onset of clinical signs varies among patients. In some patients, clinical signs appear over a few days; in others, they develop over several weeks. There is progressive tetraparesis, hyporeflexia, and atrophy of proximal skeletal muscles. Sensory deficits are not apparent.

Electrodiagnostic evaluation typically shows denervation of limb muscles, relatively normal nerve conduction velocity, and markedly decreased amplitude of M waves. Results of histological examination of peripheral nerve biopsy specimens are usually normal; however, similar examination of intramuscular nerves sample might be diagnostic. Distal intramuscular axons degenerate with collateral axonal sprouting.

Treatment for distal denervating disease is supportive. The prognosis for affected dogs is excellent; dogs typically recover in 4–6 weeks. Relapse has not been reported.

Distal polyneuropathy of Rottweiler dogs is characterized by paraparesis that slowly progresses to tetraparesis, hyporeflexia, and muscle atrophy. The clinical course can be progressive or can wax and wane. The cause is unknown but is believed to involve a degenerative process.

In one study, nerve and muscle biopsies were examined from eight Rottweilers (six males and two females) aged 1.5–4 years (2); however, an age or sex predilection has not been definitively established.

Electrodiagnostic testing shows denervation in distal muscles of the limbs and decreased motor nerve conduction velocity.

Histopathological changes on nerve biopsy consist of axonal necrosis and demyelination, often with infiltrates of macrophages; these changes are most severe in distal nerve fibers.

The prognosis for Rottweilers with distal polyneuropathy is poor; however, some dogs temporarily improve with corticosteroid treatment.

Geriatric onset laryngeal paralysis and polyneuropathy (GOLPP) is common in older large-breed and giant-breed dogs, especially Labrador Retrievers.

The earliest and most prominent clinical signs of GOLPP are related to laryngeal paresis; they include voice change, laryngeal stridor, and a dry cough. In severe cases, bilateral laryngeal paresis leads to exercise intolerance and episodes of respiratory—especially inspiratory—distress and cyanosis. Affected dogs have can also have subtle clinical signs of a generalized polyneuropathy, such as limb weakness, ataxia, proprioceptive deficits, and esophageal weakness.

Abnormal esophageal motility, in combination with laryngeal weakness, predisposes patients to aspiration pneumonia.

Diagnosis of laryngeal weakness is based on laryngoscopic evaluation while the patient is lightly anesthetized. Findings include unilateral or bilateral lack of abduction of the arytenoid cartilages and vocal folds during inspiration. Neurological examination might show pelvic limb ataxia with decreased postural reactions and weak spinal reflexes. Thoracic radiographic imaging is recommended to evaluate for megaesophagus and aspiration pneumonia. Serum biochemical analysis and assessment of thyroid function are important to rule out treatable causes of polyneuropathy.

Treatment of GOLPP depends on the severity of clinical signs. Dogs with only mild stridor or voice change are managed conservatively; recommendations include using a harness rather than a neck collar, avoiding exercise in hot weather, and weight loss if indicated.

Surgery, such as unilateral arytenoid lateralization, is indicated for patients with severe inspiratory dyspnea. Surgery does not restore normal laryngeal function but usually diminishes severe inspiratory dyspnea. A potential complication of surgery is aspiration of food or liquid.

Physical therapy might help slow the progression of limb weakness and incoordination.

Idiopathic facial paralysis is a common disorder in dogs and cats that results in unilateral or bilateral paresis or paralysis of the facial muscles. Cocker Spaniels, Pembroke Welsh Corgis, Boxers, English Setters, and domestic longhair cats are at increased risk. The cause is unknown.

Clinical signs include acute onset of unilateral or bilateral inability to blink (see dog facial paralysis video in Facial Paralysis in Animals), drooping ears, drooping upper lip, and drooling from the corner of the mouth. Facial sensation (mediated via the trigeminal nerve) remains intact.

Diagnosis of idiopathic facial paralysis is based on clinical features and exclusion of other causes of facial paralysis, including ear disease, trauma, and brainstem lesions.

Histopathological findings consist of degeneration of myelinated axons in the facial nerve, typically without evidence of inflammation.

There is no specific treatment for idiopathic facial paralysis. Application of artificial tears to the eyes often helps to prevent corneal damage. Partial improvement might occur in a few weeks; however, persistent dysfunction is common.

Chronic facial nerve paralysis can result in denervation atrophy and fibrosis of the facial muscles. The shortening of facial muscle fibers causes facial muscle wrinkling, caudal displacement of the ear and the lip commissure, and blepharospasm on the affected side. In some cases, the nose is also deviated to the affected side.

The clinical appearance of idiopathic facial paralysis can resemble that of hemifacial spasm, which is characterized by constant, active contraction of the facial muscles. Hemifacial spasm is caused by facial nerve irritation—for example, by inflammation or neoplasia. The difference is that the palpebral reflex is intact or even exaggerated with hemifacial spasm, whereas it is absent with chronic facial paralysis.

• What Every Dog Owner Needs to Know About GOLPP. Morris Animal Foundation.

• GOLPP – Geriatric Onset Laryngeal Paralysis and Polyneuropathy.

• Managing Megaesophagus in Dogs. Veterinary Partner, VIN.

• Van Meervenne SAE, Bhatti SFM, Martlé V, et al. Hemifacial spasm associated with an intracranial mass in two dogs. J Small Anim Pract. 2008;49(9):472-475.

• Also see pet owner content regarding degenerative disorders of the peripheral nerves and neuromuscular junction in dogs, cats, and horses.

1. Shelton GD, Coates JR, Steiss JE, et al. Congenital myasthenic syndrome in Doberman Pinscher dogs is associated with a homozygous missense variant in AGRN. Biomolecules. 2026;16(8):1099. doi:10.3390/biom16081099

2. Braund KG, Toivio-Kinnucan M, Vallat JM, Mehta JR, Levesque DC. Distal sensorimotor polyneuropathy in mature Rottweiler dogs. Vet Pathol. 1994;31(3):316-326. doi:10.1177/030098589403100304