Three generations of Amelia Dowe's family have been diagnosed with Parkinson's and while she harbours some worry for herself and her brothers, the 18-year-old isn't scared.

"There's no point for us to live in fear of what may or may not happen," she told AAP.

"At the moment, there's no tests, no anything to know if or when it will express.

"But hopefully there's still a lot of time."

Ms Dowe's family can take heart from a new study that will investigate the impact of a common familial gene mutation associated with the disease.

Its cause is largely unknown but about 15 per cent of those diagnosed have a family history and this can result from genetic mutations, according to Johns Hopkins Medicine.

Most humans have two copies of every gene but mutation issues can result in some havin

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