The Commission of Investigation into alleged abuse in a foster home in the south east is to focus on the care of the woman known as Grace before any other cases are examined, the Irish Independent has learned.
It comes as her birth mother spoke of the "living hell" she's experienced since learning of the allegations about how her daughter was treated in the home.
Disabilities Minister Finian McGrath is to bring the terms of reference of the inquiry into the case to Cabinet for approval today.
It is understood that the initial focus of the Commission will be on Grace, the disabled woman allowed stay in the home for 20 years, 13 of which came after allegations of abuse in the home were first made.
The Commission is to produce a final report after 12 months. The terms of inquiry are to leave open the possibility of further cases being probed in a second module after that.
A total of 47 children lived in the foster home over two decades and concern has been raised about four other cases of alleged abuse.
The Commission is also to examine the involvement of minister Michael Noonan - who held the health portfolio in the mid-90s - and his then junior minister Austin Currie.
The foster parents wrote to Mr Noonan in 1996 in an effort to appeal a plan to remove Grace from the home. There is no suggestion he intervened on their behalf.
The Health Department previously insisted that neither minister sought to influence the decision in the case.
Grace's birth mother last night told RTÉ she rejects a written apology from the HSE saying she felt "it wasn't coming from the heart".
She added: "No one from the HSE ever picked up a phone and apologised to me or asked me how am I doing?"
Last night a HSE statement said: "It is genuinely to our regret but we understand why Grace's mother cannot accept our apology now.
"We do hope that in the future she may be in a position to do so."
The statement said it was important that any remaining questions she had were answered by the Commission.
The HSE pledged to co-operate "in every way to assist" the inquiry.
"Once again, the HSE can only apologise to Grace and her mother and say that we genuinely are very sorry for all of the failings in her care and in our system," the statement added.