Motor neuron disease
Channel: all the knowledge of the universe PRINCIPIA
Date: 2021-12-02

Motor neuron disease, by Wikipedia https://en.wikipedia.org/wiki?curid=876 / CC BY SA 3.0

#Motor_neuron_diseases
#Rare_diseases
#Systemic_atrophies_primarily_affecting_the_central_nervous_system
Motor neuron diseases or motor neurone diseases （MNDs） are a group of rare neurodegenerative disorders that selectively affect motor neurons, the cells which control voluntary muscles of the body.
They include amyotrophic lateral sclerosis （ALS）, progressive bulbar palsy （PBP）, pseudobulbar palsy, progressive muscular atrophy （PMA）, primary lateral sclerosis （PLS）,
spinal muscular atrophy （SMA） and monomelic amyotrophy （MMA）, as well as some rarer variants resembling ALS. Motor neuron diseases affect both children and adults.
While each motor neuron disease affects patients differently, they all cause movement-related symptoms, mainly muscle weakness.
Most of these diseases seem to occur randomly without known causes, but some forms are inherited.
Studies into these inherited forms have led to discoveries of various genes （e.g. SOD1） that are thought to be important in understanding how the disease occurs.
Symptoms of motor neuron diseases can be first seen at birth or can come on slowly later in life.
Most of these diseases worsen over time; while some, such as ALS, shorten one's life expectancy, others do not.
Currently, there are no approved treatments for the majority of motor neuron disorders, and care is mostly symptomatic.
A man with amyotrophic lateral sclerosis （ALS）.
（A） He needs assistance to stand.
（B） Advanced atrophy of the tongue.
（C） There is upper limb and truncal muscle atrophy with a positive Babinski sign.
（D） Advanced thenar muscle atrophy.
Signs and symptoms depend on the specific disease, but motor neuron diseases typically manifest as a group of movement-related symptoms.
They come on slowly, and worsen over the course of more than three months.
Various patterns of muscle weakness are seen, and muscle cramps and spasms may occur.
One can have difficu...