Rosie McLoughlin died aged just 14 on Saturday after a long battle with the brain disorder Rett Syndrome.
Coleen returned home early from her holiday to Barbados to be at her sister's side. She said "We are absolutely heartbroken to have lost our angel." Sarah Rogers reports.
For more information go to the Rett Syndrome Research Trust UK website.
You can also find out about the work of Claire House Hospice at www.claire-house.org.uk.