Motor neurone disease (MND) is a term used to describe a group of diseases that affect nerve cells called “motor neurones”.
Motor neurones normally carry messages from the brain to the muscles via the spinal cord. The messages allow people to make voluntary movements like walking, swallowing, talking and breathing. With MND, however, the nerves become damaged and start to die so muscles gradually get weaker and waste away. Currently, there is no cure for MND and it is life shortening.
The speed at which MND progresses and survival times varies in each person.
Talking with a neurologist is a good place to start learning more about what to expect with MND. Neurologists and MND clinic staff can also help in talking about treatments and support available to help quality of life. While MND is life shortening, research has shown that a team based approach and timely treatments can help people with MND live better for longer.
Early signs of physical problems or other symptoms of MND may be mild at first. Symptoms may include stumbling due to weakness of the leg muscles, difficulty holding objects due to weakness of the hand muscles, or slurring of speech and swallowing difficulties due to weakness of the tongue and throat muscles. Where the weakness in the body starts depends on which motor neurones are affected first.
The diagnosis of MND by a general practitioner (GP) or other physician is often difficult. Sometimes it is necessary to review a person for a period of time before a diagnosis can be confirmed. A general practitioner may suspect a problem with muscles, the brain, nervous system or other neurological issues and organise referral to a neurologist (a doctor who specialises in disorders of the brain and nervous system). Several other neurological conditions resemble MND, especially in the early stages, and need careful exclusion.
The diagnosis can be assisted through a range of tests, including:
In 90-95% cases of MND the cause is unknown. In the other 5-10% of cases a genetic mutation is the cause of the disease. The mutated gene is inherited from a parent. Inherited MND is also known as “familial MND”.
There are many theories about the causes of MND. Theories include exposure to environmental toxins and chemicals, infection by viral agents, immune mediated damage, premature ageing of motor neurones, loss of growth factors required to maintain motor neurone survival, ageing and genetic susceptibility. Ongoing research throughout the world is looking for causes.
It is thought that any of these potential causes may act individually or in combination to contribute to the development of MND. Recent research suggests a six-step process with genes, environment and ageing contributing to the development of MND.
Research focused on environmental causes understandably often provokes intense media and community interest. Some studies may report an association, but it is important to note that association is very different from cause. The causes and disease mechanisms section from the UK's MND Association research blog provides an overview of recent research on potential causes of MND.
In recent times the pace of genetic mutation discovery has accelerated due to advancements in technology and a concerted international collaborative approach. It is now possible to test for the presence of mutations in the SOD1, TDP43, FUS and C9orf72 and other recently identified genes in a person diagnosed with familial MND.
Research is increasing our understanding of the mechanism by which these mutations cause MND and may lead to treatments which can prevent or delay the onset of MND in someone with an MND-related genetic mutation. Clinical trials of therapies targeting SOD1 and C9orf72 mutations are currently underway.
Genetic testing for people with a family history of MND requires careful discussion and referral for professional genetic counselling prior to testing.
The MND Decision Support Tool - Should I have predictive genetic testing for motor neurone disease? - is designed to help people discuss their choices with their doctor or genetic counsellor.
It is estimated that in Australia, at any one time, around 2,100 people are living with MND. Every day two people are diagnosed with MND in Australia and two people die from the disease.
Although the lifetime risk of developing MND is about 1 in 300 by the age of 85, with risk increasing steadily as people get older, many people have not heard of MND before they themselves, or someone they know, has been diagnosed.
Slightly more men than women are diagnosed with MND, and most commonly they are in the 50 to 60 year age group. However, MND may be diagnosed in adults at any age.
Globally, over 400,000 people are currently living with MND. MND affects people from every country and ethnicity in the world.