Early-onset Parkinson's gene identified

Researchers have identified a gene linked to early-onset Parkinson's disease.

They suggest that identifying the effects of individual genes at different ages could lead to a more personalised medicine.

'We want to have a more comprehensive understanding of what these genes related to Parkinson's are doing at different points in someone's lifetime. Then, with genetic testing, we can determine the risk for illness based on someone's age, gender, weight and other intervening factors,' said Dr Auriel Willette from Iowa State University, one of the lead authors on the study, which was published in the journal Neurobiology of Aging.

The researchers investigated the gene GCH1 in 289 Caucasians who had been recently diagnosed with Parkinson's disease but who were not yet on medication, and compared them with 233 healthy controls. Those who had one 'bad version' of the GHC1 gene had a 23 percent increased risk of Parkinson's disease, and they also developed the disease five years earlier than people without the mutated version of the gene. The gene was associated with a much higher risk in younger people, whereas the gene only had minimal effects in people over the age of 50.

Parkinson's disease is a progressive neurological movement disorder that particularly affects the motor system, causing tremors and rigidity, and it can also affect cognitive functions. The motor symptoms are caused by reduced dopamine levels in the brain's substantia nigra. Several genes have been implicated in the disease, but each on its own poses only a small risk.

'As we age, we progressively make less dopamine, and this effect strongly outweighs the genetic influences from the bad version of this gene. Simply by ageing, our dopamine production decreases to the point that the effects from a mutation in this gene are not noticeable in older adults, but make a big difference in younger populations,' explained Joseph Webb, one of the researchers on the study.