A young brother and sister who suffer from the rare Batten disease met the President at the weekend to celebrate one of their birthdays.

Saoirse (5) and Liam (2) Heffernan suffer from the fatal genetic condition, and they are waiting for a chance to receive life-saving treatment in America.

But Liam, who turned two on Saturday, was invited to lunch by President Mary MacAleese with his family.

Their father, Tony, made the request that they meet the President, because he does not know how much longer his children will live.

"We said we'd love to meet the President because we don't know how long or how short their lives will be, and we feel that everyone should visit the Aras at some point in their lives," he said last week.

"It's Liam's birthday and Obama wasn't available for us so we're going to meet herself instead," he joked.

Saoirse and Liam both have Batten disease -- a rare genetic, degenerative neurological disorder -- and without the radical treatment in the US they will die.

"We're ecstatic that we got the invite. Mary's [Tony's wife] mother gave up work to move in with us and help us, so she's coming along with us as well. We'll have a private meeting with President MacAleese, and then the garden party and lunch entertainment."

Meanwhile, Saoirse and Liam were reunited this week after Liam contracted two viruses and had to be separated from his sister while he recovered.

"Saoirse had to go in to hospital for a special infusion of a blood clot to improve her immune system," Tony said.

The Heffernan family are bravely enduring the agonising wait to hear if Saoirse will receive life-saving stem-cell surgery in New York, after she underwent trials for it last month.

Meanwhile, the two siblings are living life to the full despite their heartbreaking condition. "Liam is full of life and enjoying everything normal that a two year-old would enjoy, and his speech is improving," said Tony.

"Saoirse is coming on well since she has had help with a personal assistant." Donations can be made to Allied Irish Banks, Main Street, Kenmare, Co Kerry, account number 06040095, sort code 93-63-24, or go to www.beeforbattens.org

© Herald.ie 2008