Jackie James said she believes their lives have been saved

Jackie James traced her half-sister on websites and found their father died of Fabry's Disease, which left his body unable to break down fat cells.

Checks then revealed she and her family also had the rare, genetic condition.

The West Sussex family are now being given potentially life-saving treatment at the Royal Free Hospital, London.

Mrs James, of Steyning, found her half-sister by contacting everyone with her father's surname from Croydon, where he grew up.

I really believe this has helped to get us treatment and save our lives, so it is a really fortunate surprise Jackie James

However, she was also suffering from symptoms she was unable to explain.

"I have headaches every day, I have joint pain, and just general pain.

"I suffer from bouts of really severe tiredness."

Her daughter, Deanne, said: "It was a really big shock to find out what happened and what can happen to you just coping as a family."

After beginning her treatment, Mrs James said: "I am pleased - it's now looking like my two older children are also going to get treatment, so that's good news."

Mrs James used internet sites to search for her father

Her consultant, Dr Atul Mehta, said the treatment would stabilise the condition and improve the symptoms.

"It is expensive, but they are important treatments which are potentially life-saving.

"We are dealing with a condition that shortens people's lives."

Mrs James said: "I went on to Genes Reunited to trace my father because he left us when I was a child.

"I registered with them and contacted people and after about a week I got a reply.

"I think with Genes Reunited and Friends Reunited, people think they are just going to trace friends or family members, but I really believe this has helped to get us treatment and save our lives, so it is a really fortunate surprise."

Enzyme deficiency

Fabry's Disease is caused by the deficiency of an enzyme which is involved in the breakdown of fats.

It leads to lipid, or fat, molecules accumulating in the body's tissues, particularly the heart, kidneys and nerves.

Men are more severely affected than women, but the symptoms depend on the individual's level of enzyme deficiency.

Symptoms can include painful sensations in hands and feet, lesions on the skin and mouth, decreased sweating ability, and clouding in the eye of the cornea and lens.

There is currently no cure for Fabry's disease, although it may be treated by enzyme replacement.

In the future it is hoped that gene therapy will be effective in overcoming problems caused by the disease.