Australia's researchers have found gene mutations which cause a rare kidney disease may also be involved in obsessive compulsive disorder (OCD), the Australian Associated Press reported on Wednesday.

Researchers from the Centenary Institute in Sydney have now identified mutations that stop the gene working properly in the kidneys, and suspect these same mutations are also involved in OCD.

They hope to develop their findings into a simple urine test that can allow earlier diagnosis of children with OCD, also known as debilitating mental disorder.

OCD patients feel intense anxiety that bad things will happen, and are compelled to practice rituals - such as hand washing or arranging objects - to prevent them.

It is known that the glutamate transporter gene solute carrier family 1, member 1 (SLC1A1) controls a protein that recovers essential chemicals called amino acids from the kidneys, but it also controls these same amino acids when they act as transmitters in the brain.

"During the past few decades studies have revealed that OCD has a strong genetic component," Centenary Institute Professor John Rasko said in a statement.

And various genetic studies had linked the disease to the SLC1A1 gene, he said, but there was no physical proof of how the gene caused it.

"Our research is a major first step towards bridging this gap," Rasko said.

The study on the gene mutations by the Centenary Institute team published in The Journal of Clinical Investigation.

It is known that the gene mutations cause a rare kidney disorder known as dicarboxylic aminoaciduria (DA).

"People with DA can be identified through a simple urine test," Rasko said.

"If this idea is confirmed in clinical trials, a simple urine test might be used to screen young children ... to identify anyone who may be at risk of early onset OCD."

OCD expert Dr Mairwen Jones from the University of Sydney says early onset OCD affects about three percent of Australians.

"The earlier we can diagnose OCD the sooner we can start treatment to manage the obsessive and compulsive behaviors," she said.

The Centenary Institute is an international consortium of researchers from the University of Sydney, the Australian National University, Universite de Sherbrooke in Canada and Royal Prince Alfred Hospital.