Project MinE, which is part-funded by the Irish Motor Neurone Disease Association, discovered NEK1, believed to be the cause of the disease.
It is hoped the breakthrough will lead to the development of treatments for MND, a rapidly progressive fatal disease which can affect any adult at any time.
One person is diagnosed with MND every four days in Ireland and around 300 are affected at any one time.
The ice bucket challenge which went viral in 2014 raised €1.6m in Ireland, with more than €600,000 spent on researching the causes and potential treatments of MND.
The Project MinE research team at Trinity College Dublin, led by Prof Orla Hardiman, played a leading role in isolating three new genes with significant roles in MND.
Project MinE brought together the efforts of over 180 scientists from 17 countries, and their work has just been published in the leading journal, Nature Genetics.
The information will be shared freely with all collaborators in the initiative and made available to scientists researching drug development.
The TCD team has started examining the full DNA profile, including rare genetic variation, in 1,000 Irish people to determine all of the genetic causes of MND.
Money raised from the ice bucket challenge in Ireland also allowed the IMDA to employ a third dedicated MND nurse and to give specialist equipment to people living with MND. The IMNDA said around half a million people across Ireland deliberately drenched themselves in ice-cold water to raise funds for the association.
The organisation said it established a reserve fund of €500,000 with money raised from the ice bucket challenge to ensure it continued until the world was free from MND.
IMNDA chief executive Aisling Farrell said the latest gene discovery showed the tremendous good that had come from the ice bucket challenge. “Again, we would like to say thank you to those who drenched themselves in ice water two years ago,” she said.