A girl caught in a life-or-death lottery for medical care could be treated - but only if doctors rule she has the right variant of a killer illness.

Sacha Skinner, aged five, was diagnosed with Batten disease three months ago but has been waiting for tests to find out if she is suitable for experimental gene therapy.

Doctors at Guys Hospital have confirmed Sacha has a strain of the disease which is the only type which would be accepted for the life-saving treatment in New York.

However, now she and her family have an agonising wait to find out if the variant of that strain, known as CLN2, will pass the vital test for treatment.

The experimental therapy is vital to Sacha and her family - it could decide whether or not the youngster lives beyond the 12 years which sufferers are expected to live.

The next stage of tests will determine if Sacha can fly to New York for a trial at Cornell University.

Batten disease is a fatal illness which affects the nervous system.

Children affected by it lose the ability to walk, talk and see.

Last week, The Argus reported how Chris Weatherstone, of Weatherstone Property Group in Hove, was so moved by Sacha's story, he offered to pay the £10,000 to send her to America.

But her parents, Annette Dacosta and Neil Skinner, of Park Crescent Road, Brighton, now face an agonising wait while Sacha's DNA is analysed in The Netherlands. The variant strain of CLN2 cannot be tested in the UK.

The results, which will determine whether she can receive the vital therapy, are not expected until Christmas.

Miss Dacosta, 37, said: "It has been a nightmare for us. We found out she had the right strain last week but then on Tuesday we were told about the variant. Normally, it all happens quickly but now we have to wait for these results before we find out if she can go to New York. Her condition is deteriorating all the time so we are just hoping she is well enough to have the treatment if she is eligible."

The treatment is not without its risks. If Sacha is accepted, she will have her head shaved so six holes can be drilled and pressure put on her brain before the replacement genes are injected.

Of the ten children who have had it, one died six weeks later but doctors are unsure if this was due to the operation or the illness.

Researchers say Sacha is a strong candidate because she is younger than most of the children who have been treated so far.

Miss Dacosta said: "Any operation is a worry and something we have to consider but we don't have any choice."

Sacha began to show symptoms of the disease two years ago and was at first diagnosed with epilepsy. But after various drugs showed no improvement in her condition, more tests were carried out and it was confirmed she had Batten disease in July.

Sacha took a turn for the worse last Friday after she contracted a virus and was unable to eat the food which contained her medication. She was admitted to the Royal Alexandra Hospital for Sick Children after she started fitting uncontrollably but doctors gave her penicillin and she was discharged on the same day.

Miss Dacosta has started fund-raising to raise awareness of the disease. She is planning a concert at Concorde 2 in Madeira Drive, Brighton. Mr Weatherstone is also planning a golf tournament in the spring.