Lady's Hospital Crumlin, in Dublin, is reviewing how a patient has misinformed that there is no cancer gene.
The patient was later diagnosed with ovarian cancer and was sick.
This includes the Clinical Genetics department of the hospital.
RTÉ News was on vacation because of the staff.
Crumlin at Lady's Children's Hospital said she could not discuss individual patient cases.
Details of the incident were reported in the Irish edition of the newspaper, The Sunday Times.
I understand that Crumlin sent a blood test for the & # 39; BRACA 1 & # 39; gene for testing at a UK hospital in September 2009.
The UK hospital told Crumlin about a positive response to the gene, but it was not passed on to the patient.
A positive result means that the patient is much more likely to develop breast or ovarian cancer than a person without a BRACA mutation.
A review of the hospital is expected to investigate whether the information was not correctly transmitted to women by Crumlin.
RTÉ News knows this year that the patient has been diagnosed with cancer and is receiving treatment.
Following the inquiry, Crumlin Hospital said in an interview with RTÉ News that he is committed to a culture that encourages an open and positive approach to incident management.
Hospitals follow the HSE incident management framework in connection with incident reporting.
The hospital said in July 2018 that Crumlin provided additional resources to support the Clinical Genetics department to improve the services.
Crumlin said a team of outside experts led by skilled health managers working in the UK are helping the Clinical Genetics department provide improved services for patients and clinical service users.