At the launch: Miriam O’Callaghan and four-year-old Liam Heffernan Photograph: Domnick Walsh/Eye Focus  At the launch: Miriam O’Callaghan and four-year-old Liam Heffernan Photograph: Domnick Walsh/Eye Focus

Up to 8 per cent of Irish children suffer from rare diseases. Their lives and those of their families are constantly consumed by the enormity o(...)