The motor neurone diseases (or motor neuron diseases) (MND) are a group of neurological disorders that selectively affect motor neurones, the cells that control voluntary muscle activity including speaking, walking, breathing, swallowing and general movement of the body. MND refers to a group of diseases that affect motor neurones. In the United States, MND is more commonly calledamyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, after the baseball player. In France the disease is sometimes known as maladie de Charcot (Charcot's disease), although it may also be referred to by the direct translation of ALS, sclerose laterale amyotrophique (SLA).

Forms of motor neurone disease include:

amyotrophic lateral sclerosis (ALS) (sometimes called Lou Gehrig's disease)

primary lateral sclerosis (PLS)

progressive muscular atrophy (PMA)

bulbar

• pseudobulbar palsy - spastic
• progressive bulbar palsy - spastic and flaccid
  
  
  
  About 90% of cases of MND are "sporadic", meaning that the patient has no family history of ALS and the case appearsto have occurred with no known cause. Genetic factors are suspected to be important in determining an individual's susceptibility to disease, and there is some weak evidence to suggest that onset can be "triggered" by as yet unknown environmental factors .Approximately 10% of cases are "familial MND", defined either by a family history of MND or by testing positive for a known genetic mutation associated with the disease.