Zebra fish with neurological disorders may provide a key to the cure of the debilitating and fatal Huntington's-like disease according to a leading researcher at Queensland's Griffith University. David King reports.

Zebra fish with neurological disorders may provide a key to the cure of the debilitating and fatal Huntington's-like disease according to a leading researcher at Queensland's Griffith University.

Dr Derek Kennedy of the Griffith University's School of Biomolecular and Biomedical Science said recent research suggested that a group of Zebra fish with neurological disorders could have a gene similar to that possessed by human sufferers of Huntington's-like disease.

"Studies done so far show the brain doesn't develop properly (in Zebra fish with this gene) and there are some fairly gross malformations going on," he said.

"We're currently trying to rescue these fish, and if we can do that, it may give us some insight to using gene therapy as a cure for Huntington's-like disease in people,"

Dr Kennedy is best known for his ongoing breast cancer gene research which has won several grants.

He and his research team discovered the gene responsible for Huntington's-like disease after it was realised that about 60 per cent of people presenting clinical symptoms similar to Huntington's disease did not have a defect in the Huntington's gene.

"They turn up at hospitals looking like they've got Huntington's disease, but when their DNA samples are checked, it turns out they don't have a defect in the Huntington's gene so clinicians send them off, saying: 'It's not Huntington's - you've got something else.

"Ten years later, they die of this horrendous thing that, in my opinion, is Huntington's, but we failed to detect it because there was no gene defect," he said.

Sufferers experience involuntary movements, personality changes, memory loss, and dementia, with death usually occurring 10 to 20 years after the onset.

The symptoms and mortality are similar to those of Huntington's disease, which is why the variation is known as Huntington's-like.

It is said to affect one in every 10,000 people, with symptoms usually becoming apparent by the age of 40. But Dr Kennedy said there was likely to be a much higher incidence since many cases had gone unrecognised or unrecorded.

There were also likely to be wide variations in the age of onset and the length of time sufferers could live with the disease.

Dr Kennedy said one patient was aged 12, and there were people who had apparently lived with the disease for 40 to 50 years.

Dr Kennedy approached the search for a Huntington's-like gene by analysing patient DNA and seeking defects in signal transduction pathways. Prior to this, there had been no advances in the search for a gene since about 1975.

While declining to name the gene responsible for Huntington's-like disease until he could publish a paper on it, Dr Kennedy said it was "not a novel gene".

"It's been in literature but it's never been identified as a gene related to any neurological disorder," he said.

There is currently no known cure for either Huntington's or Huntington's-like diseases, but Dr Kennedy said there was some hope that gene therapy could work with Huntington's-like where it had failed with Huntington's.

"With Huntington's, it doesn't mater how many normal genes a patient has, the Huntington's gene is dominant, so gene therapy won't cure them," he said.

"With Huntington's-like, it may be possible that, even if a patient had two defective genes, giving them a normal gene could override the defects."

This is where the research with Zebra fish comes in - a Zebra fish saved from death by gene therapy or other techniques may yet open the door of hope for someone with Huntington's-like disease.

But Dr Kennedy cautioned that curing people could be difficult since significant brain damage had usually occurred by the time either Huntington's or Huntington's-like diseases were clinically detected.

"We have to be able to detect these people prior to the onset, and that means screening people who are susceptible," he said.

Screening only 40 DNA samples, however, could take up to 15 years unless Dr Kennedy and his team can gain access to advanced screening equipment from the United Kingdom or the USA.

"Screening these things is huge," Dr Kennedy said. "Each DNA sample has to be cloned, sub-cloned, and sequenced, which means each sample can take weeks or months.

"If we had high temperature HPLC screening systems, we could simply feed the data into them and they would tell us if there was a defect in that gene sample or not."

Such equipment could reduce the time it would take to analyse these DNA samples to less than a year. But it would also cost between A$110,000 and A$160,000.

Dr Kennedy said there was an urgent need for such equipment in Queensland, but few genetic researchers had anywhere near the funding to acquire it.

At the time of writing, he had received just over $20,000 in grants for his Huntington's-like research.