It is possible that a genetic disorder which can increase the chances of a child developing ADHD, depression, anxiety, and cognitive problems, could be eased by taking an amino acid supplement.

PhD researcher Rachael Sharman has been studying the disorder Phenylketonuria (PKU) and said that while all babies were now tested for it, and the disease could be controlled, there were still some risks of cognitive functions being impaired.

Researcher Rachael Sharman

"With PKU, the body is unable to process a certain amino acid found in protein, phenylalanine (phe), so patients must eat a very low-protein diet to prevent brain damage," she said.

"They also have to take a lot of phe-free protein formula to ensure they are getting the other essential amino acids in protein, as their diet contains few "typical" foods.

"What we have found is that they also have low levels of tyrosine, another amino acid, which can increase the risk of low dopamine in the brain, and may be associated with ADHD and possibly, anxiety and depression.

"We want to see whether low levels of tyrosine combined with high levels of phe, are responsible for these persistent problems.

"Our hope is that, eventually, children born with PKU have no more risk of developing cognitive problems than children born without it."

Ms Sharman's PhD project involves a collaboration between QUT's Institute of Health and Biomedical Innovation (IHBI) and the metabolic clinic at the Royal Children's Hospital.

The project is partly funded by the Royal Children's Hospital Foundation, and will look at levels of phe and tyrosine to see what effect they have on the development of cognitive impairment and depression.

"This is a link we want to take further, and my study will take a direct inventory of biochemical functions of children with PKU over seven years, to see the differences in the effects of having high levels of phe in combination with low levels of tyrosine," she said.

"The answer to the PKU problem could be as simple as taking a tyrosine supplement so that the phe:tyr ratio is kept within safe levels."

Ms Sharman said that PKU used to cause severe brain damage, and any damage was irreversible, but research into the condition stopped short of completely curing the cognitive impairment of sufferers.

"Now, there are only subtle differences between kids without PKU and kids who have the condition and receive treatment for it, but the aim is to make sure there is no difference in their quality of life," she said.

"It would be the icing on the cake really, to ensure that people with PKU can reach their full potential."

**Hi-res pic available for media

Contact: Sharon Thompson, QUT media officer - 3138 4494 or sharon.thompson@qut.edu.au

Source: QUT, Queen University of Technology