The causes of motor neurone disease are not yet known, but ongoing research throughout the world is looking for causes.

There are many theories, including exposure to environmental toxins and chemicals, infection by viral agents, immune mediated damage, premature ageing of motor neurones, and loss of growth factors required to maintain motor neurone survival and genetic susceptibility.

Most cases of MND occur spontaneously. These are said to be sporadic - meaning occurring in scattered or isolated instances without clearly identifiable causes. However, familial (hereditary) MND accounts for about ten per cent of cases.

There is no evidence that motor neurone disease is transmissible from person to person.