Brexit uncertainty is causing undue stress to Irish people with rare diseases according to patient advocacy groups.
Around 300,000 people in Ireland will develop a rare disease at some point in their lives.
European citizens currently have access to a network of experts based in centres across the EU.
CEO of Retina International Avril Daly says Irish patients still do not know if they can access UK-based experts post-Brexit.
"If there was a world leader in a specific rare disease that is based in the UK, is there going to be the same access? Is it going to become much more complex?" asked Ms Daly.
"Patients with rare diseases have a lot of stress on them."
Ms Daly said that the networking of services was introduced in order to be able to alleviate problems in accessing the appropriate care.