Synonyms motor neurone disease ICD-10 G12.2 DiseasesDB 8358 | Specialty Neurology ICD-9-CM 335.2 MeSH D016472 | |
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A motor neuron disease (MND) is any of several neurological disorders that selectively affect motor neurons, the cells that control voluntary muscles of the body. They include amyotrophic lateral sclerosis (ALS), primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), progressive bulbar palsy (PBP) and pseudobulbar palsy; spinal muscular atrophies are also sometimes included in the group. They are neurodegenerative in nature and cause increasing disability and eventually, death.
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Terminology
In the United States, the term is often used to denote ALS, the most common disorder in the group. In the United Kingdom, the term is also spelt motor neurone disease (MND) and is sometimes used for the entire group; but mostly it refers to ALS.
While MND refers to a specific subset of similar diseases, there are numerous other diseases of motor neurons that are referred to collectively as "motor neuron disorders", for instance disease belonging to spinal muscular atrophies. However, they are not classified as "motor neuron diseases" by the tenth International Statistical Classification of Diseases and Related Health Problems (ICD-10), which is the definition followed in this article.
Classification
Motor neuron diseases affect either upper motor neurons (UMN) or lower motor neurons (LMN), or both: