I remember a warm, clear, still summer evening, eight years ago, when I had an unusually strong feeling of well-being as I made my way through Dean's Yard in Westminster on the way home from work. It crossed my mind as I walked that things might not always be so and that I should never take life for granted.

In fact, the first signs of being affected by motor neurone disease (MND) were just round the corner. I recall, not long after, losing my balance rather too easily while kicking a football around with my seven-year- old son. I put this down to carelessness, but after falling a few more times I found I could no longer ignore it. I also noticed that while swimming my breathing wasn't quite as easy as it should have been and that I would swallow water like a beginner.

I became uncharacteristically unenthusiastic at the thought of having to exert myself in the garden. I concluded that I had become very unfit. This was not the explanation and now I need a stick for walking and have to stop quite often to rest.

It took more than two years, many tests and three consultations with neurologists before MND was suggested in my case. Even when the consultant gave the diagnosis, he didn't go into what the disease would mean in any detail. My wife, Elizabeth, even recalls taking some comfort from the consultant's description of it as a "progressive disease": anything suggestive of progress must be a good thing, therefore MND, whatever it was, couldn't be too bad.

What was in store only began to be clear when we read the series of pamphlets from the Motor Neurone Disease Association. We learned that the disease kills by steadily paralysing the body, that neurone degeneration is unrelenting, usually rapid and that there is no known cure. Such bald revelations often gave rise to dark despair, but I was spared that initial response, perhaps because I didn't actually feel ill.

The experience of becoming disabled has its acutely disheartening moments. At home I found that I could no longer read well enough to the children to make it a pleasurable experience. In my work as a solicitor, it became apparent that it would become a major obstacle. I quickly sensed it whenever a colleague or client didn't feel comfortable dealing with me. To know I was being avoided or bypassed on account of my disability at least helped me to understand much better the often subtle and all too human ways in which discrimination arises.

A large proportion of the cases for which I was responsible for managing day to day in my job, particularly those which might involve having to use the telephone to clients or other professionals, were removed from my control. Understandably, the priority being client protection, they had to be shielded from me.

I have yet to find an alternative way of using my professional qualifications to anything like the fullest extent, even though I have a speech synthesis which enables me to speak to anyone unaccustomed to my voice.

Another grim novelty was undergoing a period of mild depression (which I learned isn't unusual among people with MND), as the implications of the disease began to take a firmer hold of me. Mercifully, this terror didn't last more than a few months, although I am daily reminded of it in the first grindingly difficult hour of the morning, when I feel exhausted and stiff, such that I can only move because the desire to escape the discomfort of the bed is stronger than my need for more rest.

It is important, though, not to lose sight of the compensations. There are the many strangers and paramedics who have assisted when I fall every few months and have to be taken to the nearest casualty department for stitching to my face. There are the courteous ushers in London's theatres and concert halls. They rarely consult me but in their well meaning officiousness ensure that I know myself to be the most important patron on the premises.

There are the medical practitioners, researchers and MND Association staff who are devoting themselves to the shared task of taming the disease and caring for those living with MND, thereby helping to bring them in from the fringes of society. A visit to the MND care and research centre is, for me, invariably a joyful experience. The medical excellence and unselfconscious dedication of everyone involved is a powerful reminder that we are not alone. Finally there are others I have met with MND whose courage is always edifying.

Good as it is, however, there are limits to what the NHS can offer. I have found physiotherapy more effective when combined with massage and receive this privately from therapists who have trained extensively in massage for people with degenerative diseases. One and a half hours with them every week often leaves me feeling so well that I am surprised to find that I am still afflicted.

There are few parts of my life which remain unchanged by the disabling effects of MND, but I know that my family is the strongest support there is against being defeated by it. When I see the children delighting in organising my high calorie diet by ensuring that I have the very richest of traditional English puddings and clotted cream teas, the recipes for which are now all grouped together under their title "Motor Neurone Specials", I realise that I have gained as well as lost since developing MND.

MND: the 'creeping paralysis'

• Motor neurone disease is a rapidly progressive neurological disorder that kills 1,200 people in the UK every year. It can occur at any age in adulthood but is more common after the age of 50. Most patients die two to five years after their first symptom. There is no cure.

• Nerve cells that activate our muscles degenerate and are not replaced. Weakness usually begins in a hand or foot and with time spreads to other parts of the body, hence the name "creeping paralysis". People are left unable to walk or talk and need assistance to feed themselves. However, touch, sight and hearing are unaffected and intellectual function is usually preserved.

• The greatest clues to the cause of MND have come from genetics and biology. In 3% of cases mutations are found in the SOD-1 gene. Mutant SOD-1 protein is toxic to motor neurones but the precise mechanism is unknown. Another recent report claims that 70% of people with MND have a defective glutamate transporter, named EAAT2. Motor neurones use glutamate to activate each other but too much of a good thing can be harmful.The drug riluzole can slow disease progression but the effect is modest. New drugs are being tested to combat MND.

Source: Dr Christopher Shaw, senior lecturer in neurogenetics and honorary consultant neurologist at King's College Hospital