Spinal Muscular Atrophy (Motor Neuron Disease)
Spinal muscular atrophy is an abiotrophic disease of somatic motor neurons in the ventral gray column of the spinal cord and brainstem nuclei. German shepherds have been reported to have focal spinal muscle
Age of Onset: 3 phenotypes
Severe form: onset 6-8 weeks (focal disease noted at 2 weeks of age)
Intermediate form: 6-12 months
Chronic: 2+ years
Severe form: onset 6-8 weeks (focal disease noted at 2 weeks of age)
Intermediate form: 6-12 months
Chronic: 2+ years
Sex Predisposition: Any sex of animal can be affected
Clinical Course:
Focal disease: Clinical signs progress rapidly within weeks
Severe form: clinical signs progress rapidly, by 3-4 months clinical signs progress to tetraplegia and muscle atrophy
Intermediate form: clinical signs progress more slowly, resulting in tetraplegia and inability to walk by 2-3 years of age
Chronic: clinical signs develop slowly and are milder compared to the other forms if the disease (subtle paresis and mild atrophy)
Focal disease: Clinical signs progress rapidly within weeks
Severe form: clinical signs progress rapidly, by 3-4 months clinical signs progress to tetraplegia and muscle atrophy
Intermediate form: clinical signs progress more slowly, resulting in tetraplegia and inability to walk by 2-3 years of age
Chronic: clinical signs develop slowly and are milder compared to the other forms if the disease (subtle paresis and mild atrophy)
Clinical Signs:
Posture and Appearance
Limb deformities (arthrogryposis)
Movement
Tetraparesis to tetraplegia
Cranial Nerves
Difficulty with prehension
Dysphagia
Muscle Atrophy
Diffuse neurogenic atrophy (severe/intermediate > chronic forms)
Posture and Appearance
Limb deformities (arthrogryposis)
Movement
Tetraparesis to tetraplegia
Cranial Nerves
Difficulty with prehension
Dysphagia
Muscle Atrophy
Diffuse neurogenic atrophy (severe/intermediate > chronic forms)
Diffuse neuromuscular
Focal disease affecting the cervical intumescence
Focal disease affecting the cervical intumescence
Autosomal dominant inheritance - Homozygous dominant dogs develop the severe form of the disease, while heterozygous can develop the intermediate or chronic forms of the disease.
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