Vertex Pharmaceuticals Inc. said Friday that Ireland’s national health care system has agreed to pay for Kalydeco, a Vertex drug designed to treat some patients suffering from cystic fibrosis, a rare and often fatal genetic disease.

In a press release, Cambridge-based Vertex said that the Health Service Executive in the Republic of Ireland will fund Kalydeco for people 6 and older who have a specific mutation of the cystic fibrosis gene.