Researchers have investigated the mental illness in an isolated population in The Netherlands / iStock

Millions of people suffer from depression, but the genetic link remains unclear 

A gene has been linked to depression in a study which researchers hope will shed light on the little-understood condition.

To investigate the mental illness which affects over 300million people worldwide, researchers studied the genetic makeup of a group of almost 2,000 people in an isolated village in the south west Netherlands.

The team at the Erasmus University Medical Centre in the Netherlands and the Russian Academy of Sciences in Novosibirsk found that the NKPD1 gene accounted for a 4 per cent rise in the risk of experiencing the symptoms of depression. These include including feelings of worthlessness, a lack of concentration and fatigue. 

A person's genetic make-up is believed to play a role in the likelihood that they will develop the mental illness, however a single gene has not been categorically linked to the condition and environmental factors are also thought to play a part. 

The team at the Erasmus University Medical Centre in the Netherlands and Russian Academy of Sciences in Novosibirsk sequenced the DNA of participants to make their findings published in the journal ‘Biological Psychiatry’. 

The data originated from the Erasmus Ruchpen Family study into 22 families who have been isolated in The Netherlands until recent decades. Their small gene pool therefore amplifies rare variants, including NKPD1

The results were then replicated in a sample of people which represented the general population. However, different variants within the NKPD1 were identified. 

“We are the first to show a possible genetic connection in this respect,” co-author Dr Najaf Amin of the Erasmus University Medical Centre said in a statement.

He added that he hopes the findings will enable researchers to target depression on a molecular level, and allow the disease to be measured and diagnosed in an objective manner. 

“NKPD1 may be one such molecular mechanism,” she said.

The findings come after researchers in Australia launched the world's biggest genetic study into depression. The Australian Genetics of Depression Study hopes that around 20,000 adults in the country will offer a swap of saliva to aid the investigation, Australia's ABC News reported.