RTE broadcaster Colm Murray and his family are in mourning following the death of his sister Cathy.
Cathy, who also worked at the station, was a popular and valued colleague, RTE said.
A broadcast co-ordinator with Morning Ireland on Radio 1, she passed away suddenly on Sunday night.
She had provided valuable support to her brother Colm, who is battling motor neuron disease (MND).
Cathy is also survived by her husband Aidan, son Conor and daughter Susan.
"RTE is very sad learn of the death of Cathy Murray, who passed away. Cathy has worked with RTE since 1979 and was an immensely popular and valued colleague. RTE would like to express its deepest sympathy to all her family," an RTE spokeswoman said.
Colm Murray (61), who was formerly one of RTE's most prominent sports broadcasters, has been living with the debilitating effects of MND for more than three years.
Last April, leading neurologist, Professor Orla Hardiman, confirmed that the former Six One News sport correspondent had lost his ability to speak.
Colm, from Moate, Co Westmeath, took part in a Reality Bites programme for RTE that documented his participation in the trial of a drug called dexpramipexole.
He went on blind trials of the drug at Beaumont Hospital in June 2011 but unfortunately his condition did not improve.
Cathy Murray began working with the Morning Ireland team in 2003, having joined the station 24 years earlier in the sales and marketing division.
She worked in television as a production assistant in young people's programmes and also worked on the 1994 Eurovision Song Contest.
She went on to take up roles in top radio programmes such as Liveline, the Marian Finucane Show and Today With Pat Kenny.