When Allen Stillwell started getting extreme headaches and losing his balance, doctors at first thought he had seasonal affective disorder.

It was only on November 5 last year that they discovered what was really wrong - a rare disease which reduces Allen's life expectancy to just 55.

By chance, a radiographer at Worthing Hospital who had worked in the United States diagnosed Allen, of Westbourne Avenue, Worthing, with Von Hippell Lindau (VHL).

The genetic condition involves the abnormal growth of blood vessels in some parts of the body causing tumours. There are only 150 known cases in Britain.

Not only did it answer what was wrong with Allen but it also laid to rest the mystery of his mother's death 25 years ago when she was just 32.

Mr Stillwell, 39, said: "It was frustrating wanting to know what was wrong with me but when I found out I was devastated.

"It answered the question of why my mother died so young but it also meant there was a chance I had passed the same thing on to my children. I felt very guilty about that."

It was ten years ago that Allen started feeling the effects of the illness.

He was forced to cut down on the amount of work he did as a self-employed plumber and heating engineer after finding that some days he could not stand up or take bright lights.

Doctors found it difficult to diagnose the problem and at that stage Allen did not link his mother's illness with his own.

It was only when he went to have a scan last autumn that doctors found he had a brain tumour and the position of it led them to diagnose VHL.

Further scans revealed six cysts on his kidneys and seven cysts on his retinas.

After the diagnosis, Allen and his partner Tracey turned to the internet to find out more about the disease and bought as many books as they could find.

They also had the difficult task of breaking the news to his sister Sally and their children, who may all have the disease.

Mr Stillwell said: "My eldest daughter Tantara, who is six, understood that I had it but it was difficult for her to understand that she might develop it. It really develops from about your 30s onwards.

"My sister is 30 and has had some tests which have proved negative but we will have to wait and see what happens over the next few years."

Since last autumn, Allen has undergone a seven-hour brain operation, an operation to remove a tumour on his left kidney and has had all seven cysts in his eyes sealed by laser treatment.

He has been told the remaining cysts on his kidneys are harmless.

His experiences have left him with a dizziness, which he describes as feeling like a permanent hangover.

He says his view on life has changed and he is determined to live life to the full with his partner and children, Tantara, twins Mia and Ella, four, and five-month-old Freya, knowing he may only have a life expectancy of 55.

Last weekend he organised a bonfire party with family and friends and he says he is now a much nicer person to be around.

He said: "It has changed my life 100 per cent. If my sister and my children do get VHL by the time they reach my age, they will have found a cure. That is what drives me."